Journul ofthe Societv of Dairy Technolog!, Vol. 13, No. 4, 1960 I83

Mr. J. G. Inglis: 'I am very grateful indeed to Mr. Lamont for his unqualified statement. I could not really use the name of a firm in my paper, but when he gets up and speaks as boldly as he has done I am very grateful to him Tor the reason that his testimony, that of the man who is paying for the milk, is worth a great deal more than the testimony of the man who is selling it. His experience, 1 think, is one which is bound to give great confidence to buyers generally. His firm has co-operated with us right from the start. They had the courage of their convictions in saying that they would run for twelve months receiving milk from farms ninety miles away, and that I think was quite a step, because in those days one could not be sure what the effect might be. We are going to continue co-operating very happily with this firm and they are having 100 per cent supplied, and being one of the biggest dairies in Scotland, it is quite a large depot.

Mr. Enock raises a point, with which I am very much in sympathy. I think one of the reasons why there are so many sizes is again the high cost, and if you can trim say f50 or fl00 off the expense and buy a slightly smaller one, there is an inducement to do so. When we started off it was with four sizes, I think, for Scotland and five in England (they wanted one a bit smaller than we did) and we tried very hard to maintain that. But a tank manufacturer produced two or three farmers and brought them to my office only a few years ago and the farmers were put up to say, "Look, you spe-ify 350 and 250 gallons, but here is a man who is making a 300 gallon tank. which is what I want. Why should I not have it?" I found it difficult to answer and the result, Mr. Enock, is the variety of sizes we havc today. 1 am sure we would all like to see fewer tank sizes and I think that will come if costs can be reduced. The point is very important, too. in the development Mr. Hall referred to of twice or three times a week collection, which I was delighted to see

was taken so quietly by all the Public Health Department authorities who are gathered here today.

Mr. Hall did bring up the question of quantity, and I am glad he had to answer the question from the local farmer and not me. Measuring by the broad and perhaps unscientific way we have to handle i t does work out satisfactorily, as I have said. We are getting rather better results than we did with cans, which is difficult to explain but that is just what happens. You realize that when a tanker is doing two or three journeys we cannot have it standing in the yard for two or three hours to let the foam go down and so forth. Therefore the methods of trying to conduct a scientific experiment in the midst of a busy enterprise would be rather difficult. Those are the results so far, and I am sure Mr. Lamont, friendly as we are, would not have hesitated to say if he thought he had paid for a gallon he had not received.'

Mr. H. S. Hall: 'Could I say very briefly something about this question of tank size? What I would like to see happen is the abolition of tank sizes so far as specification is con- cerned. My feeling is that duc to the pressure which Mr. lnglis has described, we now have six or eight sizes in the specification, and there is the tendency for a manufacturer to think, "My competitors will be offering a whole range and so I must do so". I think the best way to combat that is to cut out sizes altogether, to leave each manufacturer to decide for himself how many sizes and what they shall be. He will realize the force of what Mr. Enock has said, that the more sizes he makes the more it will cost him, and the mere matter of competition will therefore keep him in check. He may well then decide to offer three sizes, and another manufacturer may offer also three sizes which may not coincide exactly with the first manufacturer's sizes. I would prefer to see complete freedom to the manufacturer in this matter.

* * *

Mr. W. B. Sampson: 'Ladics and Gentlemen, we now come to our second paper this morning on "Recent Advances in Creamery Practice in Scot- land" to be given by Mr. J . H . Smith.

Mr. Smith is another newcomer to Scotland, at least in the milk world; but he is a Scot and a son of a very well known member of the milk industry. Mr. William Smith, who must be known to many

of you. Mr. Smith is a product of the Glasgow College, and having gone through the College he then joined the United Creameries Ltd. and has specialized largely in milk products. Having been on that work in a very practical fashion, he has now come back to Glasgow as a Technical Executive.

I have much pleasure therefore in introducing Mr. Smith to you and asking him to give his paper.'

(Fourrh Paper)

RECENT CREAMERY DEVELOPMENTS IN SCOTLAND BY J O H N H. S M I T H

Technical Executive, United Creameries Ltd.

Introduction When asked to assess recent developments in Scottish creameries I felt this could best be done by dealing primarily with our manufacturing cream- eries, principally those concerned with the manu- facture of butter, condensed milk and cheese. The many changes in the techniques of cheese produc- tion have also received special attention in this paper.

Early this spring, therefore, I visited a number of our most up-to-date creameries in the south-

west of Scotland from which several trends were observed and these form the basis of this paper.

There are three Milk Marketing Boards in Scotland, two in the north and the Scottish Milk Marketing Board which handles over 80 per cent of all milk produced in Scotland today.

The North of Scotland Board operates creameries at Kirkwall, Wick and Nairn. Milk surplus to the liquid requirements is made up into butter and skim milk powder. This Board has recently installed one

184 Journal of the Society qf Dairy Technology, Vol. 13, No. 4, 1960

of the latest types of butter churn and is well known for the high quality of butter it produces.

Aberdeen and District Board have recently moved into mw premises at Bucksburn where a modern plant handling up to 10,000 gal./h. has been established. This plant also manufactures butter, cream, milk powder and a certain amount of pre-condensed full cream milk. The latest types of plant have been installed which include the Silkeborg ‘Top’ churn. Steam requirements in the region of 40,000 Ib./h. have been met by the installation of three fully automatic oil fired package boilers operating at about 250 p.s.i.

The majority of our manufacturing creameries, are, however, in the west and south-west of Scotland where dairy farming predominates. Most of these creameries were established early in the present century to cool liquid milk for the central industrial area, also to handle the seasonal surplus. Additional creameries were built or acquired by the main Board in the early thirties. The steady increase in milk production since the war soon began to strain manufacturing facilities at that time and expansion became inevitable.

While this expansion has been met, as in other parts of the country, by using existing premises to the highest level of efficiency, in Scotland there has been a definite trend to work with larger and larger manufacturing units. Cheese vats holding over 2,000 gal. of milk were installed sometime ago at Dalbeattie. A 100-box butter churn was installed at Mauchline. Mechanical cheese vat stirring was first developed on a commercial scale at Stranraer. Increasing labour costs and shortages of trained staff led to the development of the two-level system of cheese making at Colfin. The use of such units and techniques has in turn paved the way for the increased application of mechanical handling to speed production and further reduce labour requirements.

All these factors have combined to establish creameries which today, though sometimes modest in size and appearance, are nevertheless very often highly mechanized, use the latest types of equip- ment and achieve relatively high outputs per person. Tradition dies hard in the dairy industry but these methods, though initially received with caution, have now become generally widespread.

Research and development of new materials in other fields have also helped our own industry, and today materials such as stainless steel and plastics which only a few years ago were regarded as prohibitively expensive are now finding extensive application in our creameries. Increasing output and the maintenance of consistently high standards have focused attention on the need for efficient laboratory control. There has been a marked expansion in this aspect of our creameries. Critics may well feel that the craftsman is being supplanted by the analyst and technologist, but I feel sure that

the expanding use of these facilities has contributed materially to our methods and standards of manu- factug. The Lewis system of starter propagation and control is but one example of methods being extended directly to help solve practical problems in the cheese room.

Undoubtedly one of the most interesting trends recently has been the demand for a smaller direct marketable unit, as shown by the steadily in- creasing sales of packet butter and the demands for smaller size cheese wrapped or dressed in more attractive ways. These trends occasionally lead to some modification of well-established manufac- turing processes which in turn creates new problems for our creamery managers. Not the least of these is the retention of the traditional high quality of our products while meeting the demand for new methods of production and packaging. Neverthe- less the overall picture was one of increasing scope for integrated systems of manufacture by which means costs might be reduced or kept relatively stable, thereby allowing our dairy products to face ever-increasing competition from other foods.

Condensed Milk The manufacture of condensed milk in Scotland last year accounted for nearly 29,000,000 gal., second only in importance to cheesemaking. In common with the rest of the country most of this production has been in the unsweetened condensed form (‘evaporated’) and Scottish production is almost entirely by private manufacturers, although a certain amount of milk is pre-condensed at Bucksburn for despatch to Dumfries.

Condensed milk production is somewhat special- ized. As a result, information on recent develop- ments tends to be closely restricted and few details have become available for inclusion in this paper.

The largest condensery in Scotland is at Dumfries where the daily intake is over 100,000 gal. It also imports pre-condensed milk from Aberdeenshire.

At Kirkmichael, production and despatch of full cream condensed milk is carried out in bulk and a good trade has been developed in recent years with baking and confectionery concerns.

At Campbeltown production has mostly centred on machine-skimmed sweetened condensed milk, the cream being used for butter. This plant can handle up to 20,000 gal. per day.

Among recent installations has been a Stork pre- heater which, utilizing regeneration and heat treatment of milk under pressure, can pre-heat milk from 150-275°F. and subsequently cool the outgoing milk to 190°F. A high degree of control can be exercised by a special three-way valve and facilities are available for immediatestopping should the electricity or steam supply fail. The machine is never stripped for cleaning, this being done by chemical cleaning methods after which it is left standing overnight filled with clean water. This

Journal ofthe Socic~ty of' Dairy Technology, Vol. 13, No. 4 , 1960 185

186 Journal of rhe Society of Dairy Technolcgy, Vol. 13, No. 4, I960

Creamery

TABLE I Scottish Butter Making Creameries

PACKING _. ~~~ -~ CHURNS -

Bulk Packet

Type Production Bulk Packer

I B

C

D -___

E

G

H

1 I Wood 1 100 box 11 Packet 1 - 11 BMRMKIII 110 I f A II ANDERSON I I Benhill t

ANDERSON

ANDERSON 1 1 S. Steel 50 ,, A~TRA 1 1 Wood 30 ,, Bulk SILKEBORG I 1 wood 16 ,, ANDERSON , I 1 S.Steel 50 ,, Bulk 1 Johnson

717 60 ,, i Bulk only Anderson

- - 1 - - ~ _ _ _ Bulkand 1

SILKEeORG 'TOP' %Steel 60 ,, Packet I Johnson Kustner 80 f ~~

111 Wood 1 - I - ! - 111 ~ _ _ _ _ _ _ _ _ _

ANDERSON 50 ,, Bulkonly 1 Anderson

1 2 I Wood 20 ,, ASTRA 15 ,, Bulk

SILKEBORG Wood 20 ,, 1 f ' Wood 30 ,, Bulk ! None

_ _ _ _ _ _ _ _ _ _ _ ~

Wood I None - / - I - - / - I -

1-1

10 ,, 1 1 1 1 Wood

J / I SILKEBORG 1 1 Wood I 20 ,, 11 Bulk 1 None - - I-,- _ _ _ _ _ ~ - - ~ K 11 SILKEBORG 'TOP' I , S.Steel I 20 ,, Bulk 1 None 1 - I : I -

f 1 %k?d I None I B.D.R. - 4

Wood 14 1 ' Wood I 7 :: I/ Packet - I/ Kustner 1 - 1 4 L 1/&TRA

machine has operated very well indeed and has given milk with excellent viscosities.

Scottish production of full cream condensed milk last year amounted to 49,000 tons.

Butter Nearly 24,000,000 gal. of milk went to butter production in Scotland last year; this represents 26 per cent of the total manufacturing gallonage and about 4,700 tons of butter. Traditionally the outlet for milk surplus to other manufacturing require- ments, much of this production was carried out by the three Milk Marketing Boards who operate 9 out of the I2 butter-making plants in Scotland (Table I).

METHODS OF MANUFACTURE The basic principles of butter making have not undergone extensive change in recent years ; the main trend has been the introduction of new types of equipment. Milk is usually separated at 98- 110°F. to give a cream of about 40 per cent butter- fat. It is then pasteurized, usually in stainless steel pasteurizers of the APV HX type, to about 190°F. and cooled to a suitable temperature. Where

ripening is carried out, enough starter is added to ensure a churning acidity of '0~14-0*185 per cent. Sweet cream is either passed directly to jacketed ageing tanks usually fitted with mechanical agitators, or to 200-gal. rocking coil vats which rapidly cool the cream and age it at the desired temperature.

Some variation in the fat percentage of the cream churned and in the churning temperature was noted; churning is usually at about 38 per cent butter fat and temperatures ranged from 42"-46"F. Much of the butter produced is cold stored for subsequent use and washing is usually done. Opinions varied as to whether salting was necessary for cold-stored butter. Where salting was carried out, enough was added and worked in to give about 1.5 per cent salt. In other cases butter was cold- stored unsalted.

EQUIPMENT The most recent development in butter making has been the introduction and operation of stainless steel butter churns on a commercial scale in Scotland. Two main types are in current use, the Silkeborg 'Top' churn operated by the two

Journal of the Society of Dairy Technoloxy, Vol. 13, No. 4, 1960 187

northern Boards and the Anderson Churn operated by the S.M.M.B. Board and United Creameries Limited.

The Silkeborg 'Top' churn as used by the Aberdeen and District Board has a 6O-box capacity and is fitted for vacuum operation.

Cream at 35 per cent butter fat is usually churned at about 46°F. After the churn is filled to a suitable capacity it is started up and half vacuum is applied; full vacuum is applied just before churning is completed. Among the advantages claimed for churning under vacuum are the elimination of venting, a better textured butter and a reduction in the air content of the final butter produced.

After draining the buttermilk, the butter is washed twice at 40" and 38°F. and working is then commenced.

A particular feature in the 'Top' churn is the conical design with a flattened base. By this means the butter is worked by slumping from end to end, thereby undergoing alternate compression and flattening.

Although it is possible to remove the butter by pumping, this can usually only be done when working the churn at higher temperatures and this in turn increases the possibilities of fat losses in the skim. In Scotland, the butter is removed by opening the side door and dropping it i n batches on to a stainless steel trolley waiting directly below the churn. It takes about 15-20 minutes to empty a 60-box churn.

Cleaning is relatively straightforward using hot water and a proprietary compound ; facilities also exist for cleaning the churn internally by a special cleaning turbine.

Preliminary reports have shown that the 'Top' churn is capable of turning out a first-class butter. The design permits a wide range of churning and working speeds which, in turn, allow production of a number of different types of butter from very hard to plastic. Practical operation of the churn is much simpler and butter making operations can be carried out more accurately and with a much greater degree of control.

The Anderson churns at Campbeltown and Hogganfield both have a capacity of 50 boxes and are the latest of their type.

Practical experience in sweet cream churning at Campbeltown has shown that the best results were obtained by using about 450 gal. of cream at 36-38 per cent butter fat at a churning temperature of 45°F. The churning speed is 24 r.p.m. and churning is completed in about 45-60 min. No provision has been made for venting in this type of churn, and this is accomplished by stopping, easing back the sight glass temporarily, re-tightening and starting up again. When the cream breaks, the churn is inched round to a pre-set position and by use of the hydraulic control system, buttermilk is released through the spring-loaded valve at the back of the

churn. Complete drainage of the buttermilk takes about 20 min.

Two washes are then given with wash water at 42°F. The first wash water cools the churn, draining off at about 46°F. The second wash is usually considered necessary where butter is to be cold stored for some time. When ready, the butter is dry-salted and worked to give a salt content of about 1.5 per cent. In this type of churn, working is accomplished at 16 r.p.m. by the butter mass slumping on to a series of fixed working racks. These operate satisfactorily but, as for the Silkeborg churn, care has to be taken not to overwork the butter. Working with cream of 38 per cent butter fat and churning at 44"F., the initial moisture content is usually about 13.5 per cent. This is then adjusted by the addition of water and subsequent working to achieve the required final moisture content. Little difficulty has been experienced in gaining a consistent moisture content.

After the butter has been worked, it is removed from the churn by dumping on to the special 'V' shaped trolley provided. This can usually be done in three batches and takes about 10-15 min.

After unloading, the butter is usually bulk packed and placed in a cold store for subsequent use.

Cleaning of the churn is done by using hot water at 190°F. circulated by working the churn at 16 r.p.m. for about 30 min. with the sight glass removed. After drainage, the churn is inverted to cool with the door open. Periodically, the internal surface of the churn is treated with a proprietary compound to reduce surface tension and eliminate butter sticking. Operating on the above cleaning procedure it has been found possible to keep this churn in a very high degree of cleanliness with relatively little labour.

How, then, does butter made in stainless steel churns compare with butter made in the wooden internal-worker churn ?

It has not been found necessary to modify the normal churning procedure to any extent, although in general practice churning takes about 5-10 min. longer. The main difference is in the working of the butter. Experience has shown that unless the butter is worked to a consistency slightly softer than that of butter from wooden churns, there is a possibility of leakage in cold store. Although the butter is somewhat softer from stainless steel churns it invariably hardens up overnight.

Working the butter to a slightly softer consistency may in turn create problems where it is required to packet the butter immediately after churning. This can be overcome by overnight storage of the butter in bulk in a cold room (38°F.) although it has not been found necessary in Scotland to date.

Another difference claimed in butter from stain- less steel churns is that of better spreadability and this factor may well appeal more to the consumer

I aa Journal of the Society of Dairy Technology, Vol. 13, No. 4, 1960

than characteristics such as firmness of body. Flavours in general have been very good, and it is felt that the relative ease of keeping this churn clean contributes materially to retention of the fine flavours in the butter produced.

Finally, the operation of these churns is much simpler and more positive than that of the con- ventional wooden churn. The drives are direct, elimination of internal workers has greatly reduced maintenance, and features such as electric braking and time delay starting have greatly simplified the construction and operation of the churns. There would appear to be little doubt that these churns in the course of time will gradually replace the conventional wooden churn, unless developments in continuous butter-making make this method an improvement on the standard method of churning.

In this connection, I feel that too little attention has been paid to recent developments in continuous butter-making machines. These machines were given a limited trial in this country during the early 50's and results were none too satisfactory. Today I feel that units such as the Contimab'(a French development of the Fritz patent) are well worth a further examination. Having recently seen these machines in action and examined the butter they produce, I am quite sure that they are capable of turning out butter to the standards required in this country. The hourly output available would fit in with current production requirements and Scottish butter makers would do well to give these machines a close re-appraisal.

Full Cream and Skim Milk Powder In most of our butter making plants, the main outlets for the skim produced has been the manu- facture of roller and spray dried powder. The bulk of the 13,000,000 gal. available last year was so handled, resulting in the production of about 5,100 tons of skim milk powder. Most of this drying is done over rollers, usually with skim milk that has been pre-condensed to some extent.

At Glenrothes, pre-condensing to about 32 per cent T.S. is carried out in a double-effect plate evaporator, the first of its type to be installed. This unit can forward up to 700 gal. of pre-condensed skim per hour for subsequent roller drying, sifting and packing.

Where throughput of milk into butter has been relatively large, as at Mauchline and Kirkcudbright, special facilities for handling the skim milk pro- duced became necessary. A milk powder factory was therefore established adjoining each butter plant and these were later acquired by the main Board. Both drying plants are of Grey-Jensen design in stainless steel throughout.

At Kirkcudbright, the intake into this plant can rise to over 40,OOO gal. per day which can be dried after pre-condensing, in either of the two Grey- Jensen spray drying units or a separate roller

drying unit. This plant can also manufacture full cream dried milk and ice cream powder. Milk is usually standardized, pre-heated to 180°F. and given a preliminary concentration to about 12 per cent T.S. in the collector section of the spray drying unit. It is then homogenized at 5,000 p.s.i., re- heated to 180°F. and passed to the top of the main conical drying chamber where it is atomized under pressure by a rotating spray arm. A blast of hot air entering the periphery rapidly powders the milk which falls to the bottom of the spray dryer and is extracted therefrom into the rams-horn collector. It is then sifted and finally packed in 56 Ib. bags or in the case of ice cream mix, in 28 Ib. tins. Facilities include a double-effect pre-condensing plant which helps to increase throughput at peak.

Casein Casein manufacture in Scotland has now been well established for the past few years. Acid casein production is highly specialized and our manu- facturers have been successful in establishing a top grade product, most of which is used for paper making on the east coast of Scotland and southern England. At Campbeltown, the production line has recently been extensively mechanized by the intro- duction of numerous conveyors; as a result up to 20,000 gal. of skim per day can be manufactured by a staff of five men in under 18 hr. The casein is usually sifted into three mesh sizes for despatch.

Scottish production of casein last year amounted to about 450 tons representing 3,600,000 gal. of milk.

Cheese Cheesemaking last year, both creamery and farm- house, accounted for about 36,500,000 gal. of milk and this in turn meant the production of 14,900 tons of cheese. Of this total about 500 tons was farmhouse made.

METHODS OF MANUFACTURE Before examining current methods of cheese manu- facture, a few comments on starters may be of interest.

Of the eight creameries visited, five used mixed cultures of Auchincruive origin, two used a blend of mixtures and single strains, and one creamery used single strain starters exclusively (Table 11). Auchincruive starters therefore figure prominently in current commercial cheese production, and this is a tribute to Dr. Crawford and his staff in supply- ing starters which can stand up well to long periods of hard commercial usage.

The controversy regarding the use of single strains in place of mixed cultures is well known; practical experience shows that where manufac- turing conditions and throughput permit, single strain starters can prove to be consistent and reliable. It is, however, essential to have a high

Journal of the Society of Dairy Technology, Vol. 13, No. 4, 1960

, Starters used I Luboratory -- Creamery ____-

CuIrures j Sources No. Used ~ Handling 1 held 1 daily 1

189

Bulk starter preparation ___ % Special Containers Incubation Starter System 1 Room in vat

TABLE TI

Cheese Starter Usage Scottish Creameries

~ ~ ~ ~ _ _ _ _ _ _ __-- D I SZE 1 London 3 1 Freezedried 10gal. cans I Mixed ~ Auchincruive

Mixed 1 Auchincruive 1 3 _ _ _ ~

Mother, 1 pint I Jones I Bulk tanks

I

Yes

Yes I l&-lt

A 1 Mixed 1 Auchincruive 1 2 1 2 1 10gal.cans I None 1 10gal.cans 1 No I $1 ! 12 1 2 1 Mother, 3 oz. I None 1 10gal.cans 1 No I Mixed , ” Intermediate, pints

F 1 Mixed 1 ,, 1 3 1 2 1 Quarts I None 1 Bulk tanks 1 No 1 I ~

G 1 S&$e ~

~ 25 ~ 2-3 I Freeze dried TI 10 gal. cans I Yes [r

H ! Mixed 1 ,, 1 4 ~ 3 1 Pints 1 Lewis 1 1 0 g a ~ c a n s ! Yes

____~. ~ ~ _ _ _ - 9 ,

cultures Mixed

_______ ~~

degree of laboratory control, a good stock of starters, full mechanical protection of starter propagation and an alert and able cheesemaker. Under these conditions, single strain starters will give consistently good acid production in the vat, predictable performance from day to day and firm- bodied close- tex t ured cheese.

In every case except one, starters were held in the laboratory as mothers in 3 oz. bottles or as pints. One manufacturer made regular use of freeze-dried cultures, both single and mixed strains. When used with a rotation system, these starters can be employed over long periods and give consistent performances from year to year.

The stock of starters held at each creamery varied. When mixtures were used exclusively, only two or three starters were held in reserve; where single strains or blends of starters were used, the stock rose to at least 20. Full mechanical protection for bulk starters was available in five out of the eight creameries, and throughout all stages of pronagation in three out of the eight creameries.

The amount of starter used also varied from 3 to 1 per cent with 90 min. ripening to the use of 2 per cent and 20 min. ripening. Where single strain starters were in use, about I + per cent starter and instant rennetting was the custom.

The trend at the moment is towards the use of more starter and less ripening. The method saves

time and the chance of air-borne bacteriophage contamination of the cheese milk is substantially reduced. Our graders, and many of the older members in our industry, have mixed feelings about it; but I feel that where the cheese are properly made there is relatively little difference in the final cheese itself.

In the realm of practical cheesemaking, however, our cheese makers are somewhat more cautious (Table 111). While the range of make varied from 4 hr. 20 min. to 5 hr. the usual aim was to make Cheddar cheese in about 5 hr., 3 hr. in the whey and 2 hr. cheddaring. The retention of relatively slow making times may well appear to be a pause in the steady march of progress; where making facilities and scale of throughput still allow this to be done economically there is much to commend it. The variations seen at each creamery reflected the skill and experience of the cheesemaker in handling the milk from his own locality to the best advantage.

The period of pressing has been gradually reduced. Traditional cheese usually received 48-24 hr. pressing and block cheese usually about 16 hr. These short periods of pressing have arisen both from the introduction of mechanical pressing devices and the development of block cheese production. They permit considerable savings in floor space and cheese moulds, and allow more scope for mechanical handling methods.

I90

Peak Capacity

(Gallons) per day

Creamery

Journal of the Society of Dairy Technology, Vol. 13, No. 4, 1960

Manufacturing Times Dressing Types

Ripen Make Press mins. I hrs. 1 hrs.

TABLE 111

Scottish Cheesemaking Creameries Making Methods

24,000 1 10-30 I 5+ I 24

A

B

Film Tubular

Film Tubular

-

F 1 25,000

G 15,000

H 10,Ooo ---

14,000 I Nil 1 43 1 16 1 Film Tubular

Film 60 I 43 1 18

20 4+ 18 Film Tubular

80-90 43 18 I Film

-~

-__

1 60 I 4f 1 48 I T$;ar ~ __

Tubular and 48 I Roller Band

E 1 16,000 1 60-70 I 5+

Cheddar

Cheddar

40

40,lO

Types of Cheese --

Sizes lb. Types I

Cheddar, Dunlop 70,40,10,j

' Cheddar I 70940

Cheddar 1 70,40

I 70940 Cheddar

Cheddar 70 I Cheddar I 40,lO

In general, the effect of reduced pressing time on the final cheese in store has been negligible. Where shorter pressing times are used and there are no facilities for keeping the press room warm over- night, these two factors may contribute to mechan- ical openness of the cheese made at certain times of the year.

Cheese stores were usually air-conditioned and the ripening of cheese at normal air temperature is gradually giving way to ripening under cool air storage ; this was especially marked where block cheese production was on a large scale. Where traditional cheeses were being made, strict attention was still being paid to thecontrol of temperature and humidity. Humidity control is not however essential in the storing and maturing of block cheese, and storage temperatures down to 50°F. are finding increased favour. This permits storage of block cheese for several months without their maturing too rapidly. Consumer preference lately has been for a milder flavoured cheese.

With this pattern of manufacture firmly in our minds we can now examine recent advances in milk reception and type of plant used for cheesemaking in Scotland today.

CHEESE MAKING EQUIPMENT Dairy farms in the south-west are relatively large, usually have pure dairy herds, and farm manage- ment is on a high level of efficiency.

As a result, intakes to our creameries come from a relatively small number of farms and delivery can be made fairly early in the day (Table 4). In nearly every case deliveries had been completed by noon in the group of creameries I visited, and this included intakes from 10,000-37,000 gal./day. The early reception is shown by the efficient and compact milk reception facilities seen. Fully-auto- matic or semi-automatic systems complete with conveyors were in use everywhere. Sampling devices had been introduced with some success and air- operated weighing machines such as the Avery cine weigher all helped to speed up milk reception.

In most cases milk for manufacture was made up the same day except during the peak months when it has been found expedient to carry some stock milk overnight. Bulk milk storage facilities varied but on average were about 45 per cent of the total gallonage manufactured at peak. After reception, the milk was cooled to 40°F. and was stored in stainless steel insulated tanks usually of 3,000 gal. capacity.

Pasteurization of cheese milk is universally practised but opinions varied as to the optimum temperature. The range quoted was from 152"- 162"F., but all managers agreed that the lower the temperature, the better. A return to the manufac- ture of raw milk cheese might well be possible and would no doubt be welcome by the veterans of our industry and many cheese factors also.

Journal of the Societ.v of Dairy Technology, Vnl. 13, No. 4, I960

Creamery

191

I I 1 T J ~ P of Moiiid Tjpe of Presst Type of Store

vuts

No. and Size* Mechanized

TABLE 1V

Scottish Creameries Milk Supply, Reception and Storage

Farm Supplies 1 Collection Times 1 Creamery 11 Creamerv Storage Facilities _ _ _ _

Peak ~ No. Ail. size ' Total Storage 1 of of rank 1 capacity 1 Capacity

Tanks (gal.) , (gal . ) ( %) 4 I 3,000 12,000 32.4

3,000 18,000 75.0 140

160 I 250 i 20 8.15arn. 11.30am C 1 14,000 I 3 2,000 6,000 42.8

72 570 14 17.30a.m., 1la.m. 1 D 11,000 I 2 3.000 6,000 54.5

Total Gallonrrge ' From No. 1 Largest Smallest i

560 1 400 I 20 8 l 5 a m 1 p.m ' 37,000 , ___

~- 300 ~ 30 17.40a.m. 12noon f 24,000 116

-__

100 I 400 16 ~7.30a.m.i I 1 a.m. 1 E 1 16,000 1 , 4 1,000 4,500 28.1 ~

107 300 1 3 7a.m. I Noon 1 F , 25,000 I 5 1,500 ' 8,000 32.0

80 1 800 1 8 I 7 a.m. 1 11.30 a.m. 1 G 1 15,000 )I 2 2,000 4,000 26.6

45.0 560 1 200 ~ 8 a.m. I 4 p.m. ~7~ 10,000 1'2 2,000 1 4,500 30 I I

TABLE V

Scottish Cheesemaking Creameries Equipment

E ~ 1Ox1,ooO 1 1 - I - 1 Circ. I Alpha, P. 1 Air cond.

F I 3 Y 2,500 Rect. S.G., P. Air cond.

G 1 10 x 1,OOO I + 1 -1 1 - I Rect. I T.G., P. I Air cond.

1 3 x 1,200 _-____

H 1 4 x 2,600 1 i ~ + I + 1 Rect. I S.G., P. 1 Cool air

* All vats rectangular. t S.G. = Single gang. T.G. = Two-tier gang. H = Hydraulic head.

D.L. = Double length. P. = Pneumatic head

192 Journal of the Society of Dniry Technology. Vol. 13, No. 4, 1960

Turning now to the cheese room, one of the most interesting developments in the last few years has been the introduction of the larger size cheese vats some of which have a capacity of nearly 2,400 gal. (Table V). These vats offer many advantages such as increased output in a given period and the availability of mechanized stirring, cutting and curd mixing facilities from one set of overhead gearing. There remains, however, the problem of removing the salted curd from the vat, and this is still fairly laborious. I feel there is scope here for an automatic curd elevator which, operating along the axis of the vat, would remove the curd and dis- charge it into moulds waiting at the side of the vat. Apart from this, these vats have proved satisfactory where premises permit their installations, and having a more vigorous stirring action than the well- established centrally-operated paddle, it is claimed that they produce cheese with a firmer body.

The rectangular cheese vat of 1,000 gal. capacity with the centrally-operated paddle was in use every- where. Many of these were of stainless steel con- struction. Their continued popularity is due to the relative ease of installation in existing premises, and their adaptability to the two main methods of cheddar making today. In the first method-the traditional one-all

stages of manufacture are carried out in the vat itself. This method is still generally used where the daily output in the creamery concerned is relatively small, say 10,OOO gal./day. While the capital cost of such an installation is not unduly high the method remains laborious, needs a fairly high proportion of men in the cheese room and limits production capabilities and the expansion of intake in any creamery where it is used.

The second method-alled the two-level method -is a definite improvement. In this case, the curd and whey are removed together at pitching, usually by gravity. This can be done by siting the cheese vats in a first floor cheese room directly over the cooler room, and dropping the whey and curd directly through the floor by stainless steel piping, as at Colfin. Alternatively a wider cheese room can be used with the cheese vats mounted on a platform running down one side of the cheese room; from each vat the whey and curd is run again by gravity to coolers sited beyond the end of each cheese vat at floor level, as at Sanquhar. Either system is flexible and allows fairly quick re-use of the cheese vat; women can be employed extensively and an output of 1,000 gal./person is generally feasible. When these advantages have been extended by the use of mechanical salt mixing, mould filling and pressing, the cost of manufacture can be kept quite low; and this method is one of the most economical ways of cheese making at the moment in the medium output range of say 15,OOO-25,OOO gal./day.

Milling, salting and curd mixing devices are self-

contained in the larger vats and operated efficiently and well. Where smaller vats are used the tendency has been to develop and use separate units for these jobs. There are at the moment two main types. The first one consists of two inclined conveyor belts running in opposite directions, with chutes which allow the curd to discharge from one conveyor to the other. The curd after milling and salting mechanically is thus turned back and forth for mixing. The second unit consists of a horizontal drum operating on the dough mixer principle in which the milled and salted curd is fed in batches; after mixing the curd is discharged into a waiting hopper below.

I feel, however, that these units are not fully satisfactory and that this problem still remains to be solved. In general practice, the curd is milled and salted on to a wide based trolley and after mixing is filled into the cheese moulds. There is on the market a machine for filling circular cheese moulds which, being circular in design also and limited to one type of mould, has not been adopted to any great extent.

Cheese moulds in use today are of three main types :-

1. Traditional circular, tinned steel telescopic moulds, usually 14 in. in diameter in Scotland, and turning out a 70 Ib. cheese.

2. The New Zealand 4-piece mould used on a limited scale here and which also turns out a 70 Ib. cheese.

3. Rectangular 3-piece cheese moulds which are finding increased favour and which turn out 40 Ib. cbeese. A number of makes are available today, the most recent of which are made of aluminium alloy far rigidity and lightness.

Rectangular block cheese production last yzar amounted to nearly 36 per cent of the total tonnage made in Scotland and this figure is increasing steadily year by year. The moulds themselves are easy to handle, fairly inexpensive, provide the opportunity for the extensive use of mechanical handling techniques and produce a cheese which is said to find increasing favour in the trade today. Direct sub-division of the 40 Ib. block into 4 x 10 lb. blocks is straightforward ; and these blocks when rewrapped and sold usually give a suitable size cheese with an attractive appearance, which can be easily cut to consumer size portions with relatively little cutting loss and virtually no shrinkage.

The trend for a small cheese has been met by one manufacturer in the development of 47 lb. waxed Cheddar. Waxing is carried out a few days after conditioning in specially designed drying rooms under strictly controlled conditions of temperature and humidity. This method permits the complete absence of shrinkage after waxing with retention of the traditionally shaped cheese, in an attractive

Journal of the S0ciet.r. of Dairy Techt1olog.r. Vol. 13, No. 4, 1960 I93

mould-free form. Initial results have been good and these cheese are now available to-day i n our Scottish markets.

Returning to the press room, the horizontal gang press was in general use either as a single- or two- tier press and in single or double lengths. At one creamery, space restrictions created a problem which was overcome by the installation of the Swedish Alpha Press. This consists of pneumatically operated four-tier presses in stainless steel through- out. The cheese sit on individual steel shelves in sets of four and each press holds 16 cheese at one pressing. The degree of pressure applied is easily controlled on each press and the use of this unit has allowed high density pressing in a small floor area.

Hydraulic press heads have been introduced on a small scale and can give relatively high pressure when needed. This is particularly useful where presses up to 50 ft. in length are in use. These press heads are, however, relatively cumbersome and expensive and so have not been used to any great extent in our own Scottish creameries.

The preference in Scotland has been for the pneumatic press head developed by a Scottish manufacturer, and many of the creameries visited had this type of press in either of the two forms available. In the first, the head is static and is mounted on a special end-plate. This is useful for two-tier installations and the unit is relatively inexpensive. The second type, commonly known as the 'crawler'. automatically and independently moves along the press exerting a constant pressure on the cheese. Both types have been found easy to install, maintain and operate.

Opinions vary as to the best pressure to apply, the usual pressure was about 30-40 cwt. applied over 18-24 hr. Where block cheese in double length presses were being made the pressure sometimes was raised to 6 tons.

Dressing of circular cheese is usually done by the tubular bandage. Such cheese, by virtue of their shape and method of dressing, do not lend them- selves to easy mechanization of the dressing procedure. At one creamery, this has been over- come to some extent by using power conveyors and breaking down the dressing procedure into single operations based on mass production lines. This had increased the throughput, improved the standard of dressing and made the work easier, but the system remains more of an expedient than a solution.

In block cheese production, the curd is fined into the moulds which have been previously dressed with two lining cloths which cover the cheese both lengthways and across. The filled moulds are then pressed and after a few hours each mould is re- opened, the cloths straightened and the moulds returned to the press.

The following morning, the cheese are removed

from the moulds and the cloths are then washed and sterilized for use again the same day. The cheese are then placed squarely on a film wrapper which has an internal coating of wax. After wrapping, an additional paper wrapper is applied to give protection to the film wrapper and prevent tearing during subsequent heat-sealing. During the heat-sealing process, the wax on the internal surface of the wrapper is transferred to the surface of the cheese forming an air-tight seal. Properly done, this eliminates mould growth and gives an attractive finish to the block cheese.

Until fairly recently, the wrapped cheese were replaced once again in the moulds, returned to the presses and heat was applied by pouring hot water over the moulds in the press; after cooling, the cheese were removed and re-packed for the cheese store.

The latest technique, however, employs a heat- sealing machine which seals the cheese block immediately after wrapping and eliminates the need for re-using the moulds.

Heat-sealing machines at present exist in two forms. In one, developed by a Scottish manufac- turer, the block is placed into a sealing chamber which is electrically heated. Subsequent timing of the heating operation and ejection are entirely automatic. In the second machine, developed by an English manufacturer, the basic principles are the same except that the sealing chamber is water heated and the machine itself is relatively more compact and straight forward. These machines help to produce a squarer cheese and a better sealing action is also obtained. There is also a direct saving in labour.

Where 10 Ib. blocks are being made, these are usuakly heat-sealed in the mould itself. This means extra handling and, as the demand for these blocks increases, the development of a machine to handle both sizes of blocks would be well worth con- sidering.

After heat-sealing, the 40 Ib. block or 4 10-Ib. blocks are placed in fibreboard containers with corrugated inner linings. Alternatively, they are placed in a wooden box and after a suitably shaped lid has been placed on, both box and lid are securely strapped together with wire bands. No further attention in store is needed in either case, and no turning is considered necessary. The cheese themselves are usually stored at 50-55°F. depending upon estimates of future sales. In 28 days they are graded by the Company of Scottish Cheesemakers, an organization created by the trade itself which grades and markets all cheese made in Scotlaad.

In the production of block cheeseat creamerylevel, I feel that the practical limit for sub-division is the 10 Ib. block. The additional labour needed to cut, pack and re-seal cheese in portions down to 8 oz. in size can only be justified by relatively high demands for such cheese packs throughout the year.

194 Journal of the Society of Dairy Technology, Vol. 13, No. 4, 1960

I would prefer tosee this job being done bya packing station sited nearer the main markets or by the cheese factors themselves. This would enable the trade to offer customers attractive and freshly packed cheese portions from a number of sources and also permit re-packing to definite orders.

Smaller consumer-size portions wrapped in Cryovac and Pukkafilm packs, both rectangular and wedge shaped, have been on the Scottish market for sometime now. Sales are developing but the cost of re-wrapping is relatively high and the final price to the consumer may still be a limiting factor in the development of such sales. I feel, however, that there will be a steadily increasing demand for cheese so wrapped and that prices will therefore definitely come down. The demand for such cheese, especially the 10 Ib. blocks, is certainly increasing.

By-products

The utilization of whey has always presented a problem and in the past much of the whey was fed to pigs. This outlet has now declined, however, and relatively few creameries today maintain piggeries.

Most of our creameries dry the whey (sometimes after pre-condensing) over a series of rollers from which it is ground to make whey powder. A number of creameries in Wigtownshire, however, forward the whey by road tanker to a factory at Tarff where it is condensed to about 60 per cent T.S. The condensed whey is subsequently despatched in bulk to the Midlands where it is either refined for lactose or blended with cereals for use in animal feeding stuffs. The factory at Tarff can handle up to 30,000 gal. of whey daily, all of which is imported by a fleet of road tankers.

WHEY POWDER AND CONDENSED WHEY

Conclusion The developments outlined in this paper have shown that our industry is ready and willing to meet changing demands by the adoption of new methods and establishment of new techniques. Many problems still remain. Of these, one of the most important is the need to attract more young men and women to our industry. This can only be done by creating opportunities and providing facilities comparable to those in other industries if the present rate of development and sound future of our industry is to be assured.

Mr. W. B. Sampson: ‘Ladies and Gentlemen, I am sure you will all agree that we have had a most instructive paper from Mr. Smith. His paper is a very useful one following on Mr. McAlpine’s paper of yesterday. Mr. McAlpine, as a Marketing Officer, dealt with facts and figures. Today, Mr. Smith has given us an outline of the various technical problems connected with the manufacture of the various milk products; and we will, in the course of the next few days, have an opportunity of going around some of the creameries he has mentioned and seeing the actual plants in operation. We are very much indebted to Mr. Smith.

To open the discussion we have with us Mr. Murdoch. I saw Mr. Murdoch earlier this morning and asked him for a few points about his career, but he was most reticent. However, Mr. Murdoch’s career has been a very nice balance between College work in teaching students the art of handling milk products and the putting into practice of the various points in the manufacturing of milk products with the Scottish Milk Marketing Board. I have pleasure in introducing Mr. Murdoch.’

DISCUSSION

Mr. T. Murdoch: ‘Mr. Smith. has given us a most factual survey of the manufacturing side of our Scottish dairy industry. His paper must have taken a tremendous amount of preparation and I would commend it to all students and educationists for future reference.

I could not find anything to disagree with in Mr. Smith’s paper-not that I wanted to disagree with him-but it is far more stimulating pulling something to pieces and rebuilding than merely having to applaud.

Following the sequence in Mr. Smith’s paper, I wish to make some observations and ask a few questions which I hope will help to stimulate discussion.

Continuous sterilizers are employed for evaporated milk, also automatic ejectors for any defective cans. Mention has been made of the Stork U.H.T. milk pre-heater and I must bring to your notice that Scott’s of Leven in. Scotland have designed and manufacture in stainless steel a multi-pass tubular U.H.T. milk heater. One such unit has been in use in Scotland for some years with splendid results and a number have been exported.

CONDENSED MILKS

A plate type A.P.V. double-effect evaporator has been operating for over a year on skim for powder. The small volume of product in the plant and the short time required from input to removal of the concentrate compared with conventional evaporators are the main features.

So far as the continuous buttermaking machines are con- cerned, I should like to have more information. Does the Contimab not leave a rather high fat content in the butter- milk? Can the moisture and salt contents be effectively controlled?

We have seen our conventional methods being undertaken with ever larger chums and the recent installation of stain- less steel chums of both type-non-roller barrel type and the Danish ‘Top’ type.

For the production of full cream spray milk powder during the 1939/45 war, new processing techniques were evolved together with vacuumizing and gas flushing of the containers. Such methods were adopted elsewhere as standard practice.

BUTTER

MILK POWDERS

Journal of the Societ-v of Dairy Technologv, Vol. 13, No. 4, 1960 I95

CHEESE Much depends on reliable starters and Scottish creameries have adopted the new methods of control, either the Lewis or the Jones system being practised.

Mr. Smith appears to be wedded to using extra starter and short-time ripening. In my opinion, such a practice can give good results but the matured cheese tend to be less uniform and not so fu l l flavoured.

Short-time pressing is now almost universal and this, together with metal moulds, requires more attention to he given to temperature control.

In the maturing rooms, temperature conditioning is common practice, but I cannot agree that humidity control can be ignored for wrapped block-type cheese. It has been established that for certain films the moisture content should be under 80 per cent relative humidity.

I wish to stress Mr. Smith‘s point that for good results the cheese must be properly conditioned in drying rooms having positively controlled temperature and humidity conditions. Only thus can top quality cheese be safely waxed.

I would go all the way with Mr. Smith when he states that the pre-packing of f-lb. wedges or slabs should be done by the whAesaler. Some creameries are doing this service now -yes, and making a very fine job of it-but the lines of marketing should be shortened as this trade develops.

We have been considering our Scottish creameries, but our dairies have been equally progressive. Time permits me only to catalogue a few of the main advances:-

( I ) Plate type H.T.S.T. pasteurizing is almost universal. (2) Vacuum bottle fillers have replaced all other types. (3) Automatic crating and de-crating of bottles was

established in 1953 in the Wishaw Depot of the S.C.W.S.

(4) Crate stacking and de-stacking is fairly common and Glasgow South Co-operative has employed fork-lift handling and loading systems for some years.

( 5 ) Cartons or single service containers are in common use in conjunction with vending machines.

(6) Homogenized milk is being purveyed to catering establishments and hotels.

(7) Bottled sterilized cream is freely available. Mr. Smith concluded his most comprehensive paper by

referring to one of the big problems we must solve-the recruiting of the right personnel to our industry. 1 should like to hear some opiPions on how this problem has been tackled in cther parts.

Mr. W. B. Sampson: ‘The meeting is now open for general discussion. ’

Mr. F. C. White: ‘Mr. Chairman, perhaps I could add one question to those posed by Mr. Murdoch on the continuous butter machines. I remember when they were tried out in 1947 one of the limiting factors, apart from those Mr. Murdoch mentioned, was the unit size, because most of our buttermaking plants are fairly large and would have needed so many of these little machines. I am wondering whether that difficulty has been overcome in the more modern machines.

Also on cheese wrapping, there is no doubt that waxing and film wrapping are rapidly developing. Has Mr. Smith any views on the relative costs and the relative suitability of film versus wax? Are there circumstances in which one is more or less suitable than the other in his experience?’

Miss H. R. Chapman: ’I wonder whether Mr. Smi,th could give us any idea of the cost of cheese manufacture.

Mr. J. G. Inglis: ‘I wonder if Mr. Smith would care to make

CHEESE WAXING

PRE-PACKED CHEESE

LIQUID MILK DAIRIES

an assessment of the output per man cheesemaking in the large vats compared with the system at Colfin.

Mr. W. B. Sampson: ‘If there are no more questions, Ladies and Gentlemen, I will.call on Mr. Smith kindly to give us his replies to the queries.

Mr. John H. Smith: ‘Mr. Chairman, Ladies and Gentlemen, I must thank Mr. Murdoch for the kind remarks he made.

Taking his points first of all, the high fat losses in con- tinuous butter making machines. This is a point I discussed with the French makers last year. On average we find in this country-and I mean Scotland-that our total fill losses are about 0.25 per cent. I would say 0.05 per cent in separation and 0.19-0.21 per cent in churning. When I put this to th: French people they said ‘Well frankly we cannot match that. They did say that according to their own methods of making over there an additional loss of 0.15 per cent could be expec- ted, making a total fat lcss of 0.40 per cent. That to me, although it is important, is not necessarily a serious criticism because in France and other countries they do separate the buttermilk. We may not care to do that here. I think that our losses in this country might well be. less, due to lower ambient temperatures and a different type of milk.

Regarding the regulation of moisture and salt content in this particular machine, it isessential first of all to have a good volume of standardized cream. This is normally done !y standardizing the cream in a large bulk tank with a capacity of 1,000-1,500 gal. The cream has then to be fed to the machine in a steady flow and this means you must have a balance tank above the machine.

The other limiting factor is that of chilled water. The butter is churned inside a churning chamber which is cooled by chilled water. The makers were most emphatic that ;I good supply of chilled water, kept at a steady temperature, is essential. If these points are looked after, they guarantee that these machines will turn out a butter with ;I consistent moisture content.

Regarding the regulation of salt, this is done by a special device in the front part of the machine. The machine is set working and is regulated by a device in the form of a small gate which feeds the salt in a steady stream. After taking one or two tests in the early stages, the correct setting can be established and they do say that this method will ensure consistent salting.

Coming to the point Mr. White made regarding the continuous butter making machine sizes, at the moment these are from 1,200-2,000 Ib. per hour. My point about the suitability of these machines for use in Scotland arises from our relatively smaller throughputs, and I feel that these machines could work very well with the throughputs we have here.

Cheese wrapping-the question of film versus wax. There seems to be a trend at the moment towards two types of cheese either the retention of the traditional type of cheese, that is the circular cheese, or the switch over to the block type of cheese. There is still a very good demand for traditional cheese in Scotland and I should say that six out of every ten cheese made today are still in the traditional form. The amount of block cheese being made, however, is un- doubtedly on the increase. For that reason, I think it may well be possible that more waxed cheese will be sold, because this type of cheese retains the traditional form but also has the advantages of film wrapping, that is, there is no mould growth and no shrinkage.

Regarding Miss Chapman’s reference to the cost of manu- facture. This is a very wide subject and I do not think I could give specific details of the cost of manufacture at this meeting. It does vary tremendously throughout the season, and at this time of the year our costs are relatively low. Most creamery managers would agree that there are times of the year, say in December, January or February, when they may actually be running at a loss.

Regarding Mr. Inglis’ point about the amount of labour

196 Journal of the Society qf Dairy Technology, Vol. 13, No. 4, 1960

required for the large vats at Colfin, unfortunately I have not the details of what the labour requirements are for the large vats and the comparison cannot therefore be made. I will say that in the two-level system of making as at Colfin and Sanquhar, we have found that there is a saving of about half-acrown a hundredweight over the traditional method of manufacture. The point I like about the two-level system is that relatively few people are required in the cheese room itself. For example, we use two girls and one man in the cheese room and they can handle the entire manufacture up to pitching. In the cheddaring room below, we have a staff of six or eight women and two men, and with the addition of the press house staff, we can manufacture up to 15,000 gallons of milk per day. With regard to the larger vats, the savings there are also considerable, principally in the amount of labour saved through mechanization of stirring, millin and mixing being carried out in the vat. Both systems ha$ their advantages. and their adoption can only depend on individual manufacturing policy and the amount of space available for cheesemaking plant.’

Mr. W. B. Sampson: ‘To bring this paper reading session to a close, I have much pleasure in calling on Mr. Wright of Northern Dairies Ltd. to propose a vote of thanks to the speakers.’

VOTE OF THANKS Mr. G. B. Wright: ‘Mr. Chairman, Mr. President, Ladies and Gentlemen, 1 am very pleased to undertake this duty on your behalf, although I had my doubts at one point. Let me explain that part of my duties consists of administering one or two country milk depots, and you remember that at one stage once more Mr. Inglis was sounding their death knell

loud and clear in my ears. However, as well as collecting and bulking milk, we do a lot of manufacture, and I was very comforted by Mr. Smith’s talk dealing with all this progress which is going on in manufacture. I think the keynote this morning has been progress, and we are progressive members of a progressive Society in a progressive industry, and death knells or not, 1 hope I will always be in the van of progress.

I wonder if you remembx thzt in concluding, Mr. Inglis quoted Shakespeare-in the middle of the Bums’ country a Scotsman winding up by quoting Shakespeare at an audience which consists of a fair number of people from the other s,ide of the Border, I think is a bit “much”. I did mention progress: can I now quote Shakespeare back at him? Perhaps it may be summed up as one of the characters in “Julius Caesar” says,

“We must take the curr,yt when it serves Or lose our ventures.

That sums up my attitude, and I am sure your attitude, to the very excellent lectures which we have heard this morning, both from Mr. Inglis and Mr. Smith. We are, as we must be, eternally grateful to these gentlemen who are willing to spend time and talents in preparing papers and presenting them to us so that we can enjoy this type of Conference. I am not going to forget Mr. Hall and Mr. Murdoch, and I do include them in asking you to express your gratitude and appreciation in the usual way for the wonderful time we have had this morning.’ (Applause.)

The President: ‘May I just conclude the session with my personal thanks, and 1 know yours too, to the Chairman of our Host Section for conducting the proceedings this morn- ing.‘ (Applause.)

Thursday, 2nd June, 1960

MORNING SESSION

The President: ‘Ladies and Gentlemen, the first item of business this morning is the election of a member to the society who cannot find the two sponsors required-he comes from West Pakistan. This application is from Mr. A. A. Siddiqui of Lahore Cantt, West Pakistan, and is submitted to the meetipg in accordance with Rule 7.’

Upon the application being proposed and secon- ded, Mr. Siddiqui was unanimously elected a member of the Society.

* * *

The President: ‘During the last few days in our Conference Sessions we have ranged over a large series of subjects, with cheese figuring prominently. The subject this morning, antibiotics, is one which is not only of great interest to cheesemakers but also to those who are on farm advisory work, and in a way equally to those of us who, in Joint Committee with the Milk Marketing Board, help to determine the wording of the Sale Contract. The subject of antibiotics is therefore one very prominent in the minds of members.

It has been a principle of the law of the sale of milk for many years that milk should be as the cow

gives it; but those who went before us never visualized that the teats of the cows would be treated with antibiotics and so affect the milk in this way.

As our speaker this morningwehave Mr. Ridgway of the Cheshire Sterilized Milk Company and Newhall Dairies. Mr. Ridgway has done much work on this subject, and in fact one of the directors of his company has given evidence to the Milk and Milk Products Technical Advisory Committee on this matter.

Mr. Ridgway started his career in the British Cotton Industry Research Association, and I should have thought that anyone leaving the cotton industry to come into the dairy industry would end up in ‘rags’. On the other hand, like others on the laboratory side of the dairy industry, Mr. Ridgway has done very well. After joining the Cheshire Sterilized Milk Company in 1948 he became Head of their laboratories, published papers on the bacteriology of sterilized milk and aerobic spore- formers. He was formerly a member of the Tech- nical Sub-committee of the National Association of Creamery Proprietors and of the Dairy Educa- tion Sub-committee of the Cheshire Education Committee.

Journal qf‘the Society of Dairy Technology, Vol. 13, No. 4, 1960 I97

Having helped County Councils on the right path, he has come along to help us to get on the right

lines on the subject of antibiotics. I have very great pleasure in asking Mr. Ridgway to give his paper.’

(Fifth Paper)

THE C O N T R O L OF ANTIBIOTICS IN MILK SUPPLIES UTIL IZED FOR CHEESEMAKING

B Y 1. D. R I D G W A Y

Technical Manager, The Cheshire Sterilized Milk Co. Ltd.. and Newhall Dairies Ltd.

It seems to be an unfortunate and almost inevitable facet of technological development that in dealing with one problem we are apt to create bigger ones, and it is in this frame of mind that I am approaching the questions associated with the now almost universal treatment of mastitis by antibiotics.

Incidence of Mastitis As far as it is possible to ascertain, mastitis, in one form or another, has always been an affliction of the lactating cow. I t is not easy, however, to obtain an accurate picture of the incidence of mastitis in the national herd at any one time. The Economic Advisory Council’s Report of the Committee on Cattle Diseases ( I ) concluded that about 30 per cent of the milking cattle in this country were affected with inastitis other than the tuberculous form. More recently, Laing and Malcolm (2), have described the incidence of bovine mastitis in over 16,000 cows during a period of four years, 1951-4 inclusive. This is a most interesting paper which shows that the overall incidence of mastitis during this period was 37.1 per cent. This figure included 14.2 per cent of cases of non-specific mastitis (that is, where specific pathogens were not recovered from the affected quarters). They also showed that of the cows exhibiting typical symptoms of mastitis, 38.2 per cent were non-specific, 16.1 per cent were associated with streptococci, 12.3 per cent with mixed infections and 33 per cent with staphylococci. These figures, which represent the situation after the introduction of penicillin as a means of mastitis therapy, should be compared with those given in the 1934 report ( I ) when it was stated that 90 per cent of affected animals had streptococcal mastitis.

Use of Antibiotics in Treatment of Mastitis There is little doubt that penicillin has the capacity to eliminate Streptococcus agalactiae as a serious hazard; but we do not appear to be reducing the overall incidence of mastitis which is now associated with a different pattern of organisms. The same

trend is revealed in the paper by Oliver, Dodd and Neave (3). They describe the incidence of mastitis in a herd during the period 1945-1953, a time which coincided with the introduction of penicillin. In the year 1945-46, 27.6 per cent of the cows had clinical mastitis and 37.9 per cent were infected. Of all the cows examined 22.4 per cent were infected with Str. agalactiae, 8.6 per cent with Str. dysgalactiae, Str. uheris and Group D streptococci, 15.5 per cent with staphylo-occi and 1.7 per cent with other organisms. During the next seven years, there was a gradual change of pattern and by 1952-3, 48.9 per cent of the cows had clinical mastitis and 75 per cent were infected (the mean lactation age of the cows had increased from 2.7 to 3.9). It was then found that of all the cows examined none was infected with Str. agalactiae but 32.6 per cent were infected with Str. dysgalactiae, Str. uberis and Group D. streptococci, 63.0 per cent with staphylo- cocci and 1 . I per cent with other organisms.

I have quoted only two examples of a drift which is well known to most veterinary surgeons. 1 find it difficult to describe this achievement as real progress.

But what about the mycins? We now have streptomycin, aureomycin, terramycin, neomycin; and frankly 1 find it difficult to keep abreast with the new names and almost impossible to cope with the permutations and combinations incorporated in some infusions (1 understand that one of the latest in Canada or America has no less than nine antibiotics and chemotherapeutics squeezed into one infusion). What are the mycins achieving? As far as one can see, very little indeed. In general, they do not appear to be as effective as penicillin and the net effect appears to be that more and more strains of organisms become associated with mastitis, while the incidence of mastitis itself remains at best fairly static.

I suggest that the indiscriminate use of anti- biotics has done real harm, particularly by lulling producers into a sense of false security and in so