IN THE DAIRY BY A . L . W I G G I N S

West of Scotland Agricultural College

The course commenced on the evening of Tuesday, 22nd September, when the members were welcomed by Mr. H. D. Gilchrist, the Head of the Dairying Department at Reaseheath. Mr. J. F. Hunter who, with Mr. J. Glover, was Joint Chairman of the Course, introduced Mr. R. Scott, Chairman of the Education and Research Committee, who was responsible for the inception and the organization of the course. Mr. Scott explained that, following the successful course on quality control of liquid milk, which had been held in 1965, it was felt that further courses would fulfil a need of the industry. Detergency and cleaning techniques were of great importance in all sections of the industry and it was felt, therefore, that such a course would have a wide appeal. The course, which had been limited to a maximum of 24, had been greatly over-subscribed and this had indicated the wide interest that the choice of subject had within the industry.

The first three papers dealt with the composition and application of detergents. Mr. D. Parry, Chief Chemist of the Reddish Chemical Co. Ltd., spoke on the composition of detergents. Individual constituents were described in some detail, giving their specific function alone or in conjunction with other detergent compounds, as well as their compatability or incompatability with other con- stituents. The different types of sequestrants and chelating agents were mentioned, and also wetting agents, with indications of their limitations and applications in different detergent uses. The use of chemical sterilants was described, with a brief account of some of the organic chlorine compounds. A comparison was made between the chlorine based sterilants, whether inorganic or organic, and quaternary ammonium compounds.

In the subsequent discussion, the use of liquid bottle washing detergents received much attention, and the problem of the stability of these compounds under prolonged storage was emphasized, as were methods by which this could be achieved. Chlora- mine T, used extensively on the Continent as a source of chlorine, was also discussed.

The second paper of the morning was by Mr. E. Booth, Sales Manager of the Reddish Chemical Co. Ltd., who spoke on the general use of deter- gents. Mr. Booth stated that there was a great wastage of detergents within the industry and several pertinent observations were made on problems in bottle washing which emphasized Mr.

Parry’s remarks on the subject of fobbing. Can washing was a most inefficient system where the exposure of the soiled can to the hot detergent (which is, of necessity, only mildly alkaline) was inadequate to wash the can satisfactorily. The reclamation of detergent used for CIP, the cleaning of fillers, the use of detergent-sterilizers and the cleaning of evaporators and calandrias were also described.

The questions which followed covered a range of cleaning problems : conveyor lubrication, butter churns and the standardization of detergents, all of which were discussed in some detail.

The afternoon paper was given by Mr. A. L. Wiggins, Senior Lecturer of the Dairy Technology Department, West of Scotland Agricultural College, on the practical use of detergents. He stated that all detergats were, quite simply, compounds, the function of which was to increase the cleaning power of water. Since water comprises the major part of all detergent solutions, attention must be paid to its composition and its behaviour in relation to other detergent constituents. Plant cleaning rarely received adequate attention considering that all subsequent processing operations depended on its efficiency. There was often a considerable wastage of detergents in numerous cleaning operations due to the absence of measurement, either of the detergent or the water in which they were dissolved. Mention was also made of bottle washing techniques, can washer operation and methods of selection of detergents.

The participants of the course were then divided into four groups, each group discussing a particular question posed by the speaker and a report being given on their opinions and findings. The questions dealt with the use of detergent-sterilizers in the dairy, liquid bottle washing detergents, tanker cleaning and the selection of detergents.

The second day, Mr. J. Glover, the President, took the chair. He introduced Mr. D. Jackson, Technical Adviser, The Express Dairy Co. (London) Ltd., who spoke on the cleaning of UHT equip- ment, pasteurizers and other equipment. Mr. Jackson briefly described the development of plate exchangers, the cleaning of which became more efficient with improvements in design and materials, as well as with improvements in detergent composi- tion and application. Developments in the cleaning of UHT plant had considerably assisted the

Journal of the Society of Dairy Technology, Vol. 20, No. I , 1967 41

everyday cleaning of the normal HTST plant. The system of cleaning HTST plant in which

the detergent was not recovered was described, and then the same process when the detergent was reclaimed.

The system developed for the cleaning of the UHT plant was referred to in some detail, and it was shown that the factors which influenced the time of circulation and concentration of the detergent were the quality of the milk, which was affected seasonally, and the length of the run. The cleaning of homogenizers, fillers and bottle washers was also described.

The discussion which followed showed that although few were directly concerned in the production of UHT, there was considerable interest in the technical problems involved.

The subject of group discussions included the automatic cleaning of washers and fillers, the recovery of detergents and acid cleaning. The submission of the reports provoked a markedly vigorous discussion, in which many opinions were expressed.

Instrumentation and CIP was the subject of the paper given by Mr. V. C . H. Cottle, Plant Develop- ment Manager, Express Dairy Co. (London) Ltd. Mr. Cottle dealt with the wider considerations of CIP systems and enumerated the factors which should be considered in the installation of an automatic system. The advantages of uniform systems of cleaning, satisfactory bacteriological quality and economy in labour and services were allied to those obtained by adequate instrumenta- tion. The applications and limitations of CIP on existing plants were indicated and the development of a completely automated system for UHT processing and filling systems was described.

The questions which were discussed after the paper included whether sections of the industry were fully utilizing CIP techniques, or whether the manufacturers were dictating the rate of progress, and also how the industry could keep abreast of developments in this field. Some very salient points were made, although there was little disagreement between the different groups.

The last paper was given by Mr. K. M. Banks, Manager of United Creameries, Uttoxeter, on manual cleaning processes. Mr. Banks dealt exhaustively with the numerous manual tasks in the creamery from butter packing machines to

spray and roller drying equipment. The different products presented different cleaning problems, which necessitated a different approach in deter- gency. The sterilizing agents recommended for much of the equipment were quaternary ammonium compounds .

The group discussion presented their reports on different methods of sterilization, selection of detergents, and the possible advantages that automatic cleaning would offer.

At the end of the course, criticisms were invited on all aspects of the course and recommendations for any future courses. There were no serious criticisms, the majority of the observations being laudatory. The opinion was expressed that there was some duplication in the matter covered by the different speakers, and for the repeat course there should be slight alteration in the content of the papers. It was suggested that more specialized cleaning problems could receive attention, such as cleaning of condensing equipment and also the engineering aspects of cleaning. Subjects suggested for future courses of a similar nature were effluent control and dairy legislation.

In closing, Mr. J. Glover expressed the thanks of all the participants of the course to Mr. G. J. England, Principal of Reaseheath, and Mr. H. D. Gilchrist and his staff for the assistance which had been so generously given, and for the facilities which had been made available to the Society which permitted such an interesting course to be held in such pleasant and comfortable surroundings. Great credit must be paid to Mr. R. Scott who was responsible for the overall organi- zation and for the smooth running of the course in spite of many meetings threatening to over-run the allocated time.

The value of such a course does not altogether lie in the lectures, although these were of a very high standard, but also in the subsequent discussion and exchange of practical experience, together with the contribution of the speakers. The members attending the course came principally from the higher management of the industry, and it could be argued that benefit could be obtained from similar courses by those of supervisory status, rather than management.

Since this course was so greatly over-subscribed, a repeat course has been arranged to be held at Reaseheath in April, 1967.

42 Journal of the Society of Dairy Technology, Vol. 20, No. 1, 1967