milk hygiene and evaluating milk quality - student...

MILK HYGIENE

and Evaluating

Milk Quality

HYGIENE SUSU

• Pokok Bahasan :

▫ Prinsip Higiene susu

▫ Analisis kualitas susu

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Guide to good

dairy farming practice

2004

• A joint publication of the International Dairy Federation and the Food and Agriculture Organization of the United Nations

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The overarching principles :

• From raw material production to the point of consumption, all dairy products should be subject to a combination of control measures.

• Good Agricultural Practice – GAP and Good Manufacturing Practice – GMP should meet the appropriate level of public health protection.

• Good hygienic practices should be applied throughout the production and processing chain so that milk and milk products are safe and suitable for their intended use.

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The overarching principles :

• Wherever appropriate, hygienic practices for milk and milk products should be implemented following the Annex to the Codex Recommended International Code of Practice – General Principles of Food Hygiene.

• GAP/GMP together should be effective.

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GUIDING OBJECTIVE FOR GOOD

DAIRY FARMING PRACTICE

• Milk should be produced on-farm from healthy animals under generally accepted conditions.

• To achieve this, dairy farmers need to apply GAP in the following areas:

• Animal health;

• Milking hygiene;

• Animal feeding and water;

• Animal welfare; and

• Environment.

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Microbial Pathogens in

Raw Milk

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Sources of milk contaminants

•Environmental saprophytic microorganisms: from teat canal, teat and udder skin, dust, manure, bedding material, feed, water, milking system, cooling tanks

•Pathogenic microorganisms: from diseased cows – 80 % of inflamed quarter milk samples contain pathogenic bacteria

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Groups of Human Microbial Pathogens Possibly

Occurring in Milk and Milk Products

Enterobacteriaceae

• Escherichia coli (a)

• Salmonella

• Shigella

• Yersinia enterocolitica (b)

Other Gram-negative bacteria

• Aeromonas hydrophila (b)

• Brucella abortus

• Campylobacter jejuni

Gram-positive spore formers

• Bacillus cereus (a,b)

• Bacillus anthracis

• Clostridium perfringens

• Clostridium botulinum

Gram-positive cocci

• Staphylococcus aureus (a)

• Streptococcus agalactiae (a)

• Streptococcus pyogenes

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Groups of Human Microbial Pathogens Possibly

Occurring in Milk and Milk Products

Miscellaneous Gram-positive bacteria

• Mycobacterium tuberculosis

• Mycobacterium bovis

• Mycobacterium paratuberculosis

• Corynebacterium spp.

• Listeria monocytogenes (b)

Spirochetes

• Leptospira interrogans

Rickettsia

• Coxiella burnetii

Viruses

• Enterovirus, rotavirus Enteric infection

Fungi

• Molds Mycotoxicoses

Protozoa

• Entamoeba histolytica

• Cryptosporidium muris

• Toxoplasma gondii

(a) Grows well in milk.

(b ) Psychrotrophic strains known

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Mastitis causing organisms

•Contagious

pathogens-

Streptococcus

agalactiae,

Staphylococcus

aureus,

Mycoplasma spp.

•Environmental pathogens –

Escherichia coli, Klebsiella pneumonia, Klebsiella oxytoca, Enterobacter aerogenes, Streptococcus uberis, Streptococcus dysgalactiae

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Evaluating Milk

Quality

Standard Plate Counts

• One measure of milk quality is the bacteria content of raw milk : the Standard Plate Count (SPC).

• The SPC determines the total number of bacteria in a milk sample that can grow and form countable colony forming units on a Standard Methods Agar plate when 1 ml of milk is incubated aerobically at 90°F for 48 hours.

Standard Plate Counts

• Ideally, raw milk should contain less than 5,000 bacteria/ml.

• Good sanitation in the cows, the milking procedures and the milking equipment; and cooling is adequate, a SPC of 10,000/ml or less should be achievable

• The maximum legal limit for SPC is 1000,000 bacteria/ml.

Preliminary Incubation

Counts (PI count or PIC)

• Another measure of milk quality is the Preliminary Incubation Count .

• To determine PIC, a sample of milk is incubated for 18 hours at 55°F followed by the SPC procedure.

• The PI count is based on the theory that the normal microbial flora of the cow will not grow very well when incubated at this combination of time and temperature.


Counts

• However, other microorganisms present in milk due to poor sanitation, cooling and milking practices CAN grow to significant levels at these times and temperatures.

• These microorganisms are called psychrotrophs or cold-loving bacteria. Psychotrophic bacteria will continue to grow at temperatures below 45o F.

• These organisms and the enzymes they produce are associated with off-flavors, milk spoiling and short shelf-life.


Counts

• This has led some people to believe that PIC is the best measure of raw milk keeping quality and sanitation practices on farms.

• Currently there is not a legal limit for PIC. A PIC of below 50,000 is acceptable, but a goal of 25,000 or less should be achievable.

• Many can have a PIC of 10,000 or less just like the SPC if sanitation, cooling and milk procedures are done properly and monitored.

PIC versus SPC

• Another approach for determining the quality of the milk and good practices on the farm is the PIC in relation to the SPC. If the PIC > 3 times the SPC, then there is a potential problem.

• For example a milk sample has a SPC of 10,000 and a PIC of 11,000, then no substantial increase occurred and the PIC would not imply poor cooling, milking or cleaning practices. If the PIC had been 30,000 or greater, this would imply that procedures on the farm should be checked.

Causes of High Bacteria Counts

1. Improper cleaning of milking equipment after each milking or neglecting to sanitize equipment before the next milking.

2. Wash water temperature should start at 155-170°F and drain at above 120°F.

3. Using the wrong amount or type of detergent, acid or sanitizer.

4. Gaskets, teatcup liners, rubber parts and hoses need to be clean, free of cracks and deposits and replaced when needed.

Causes of High Bacteria Counts

5. Keep your animals out of the mud! Animals with excessive or long hair on their udders may need their udder hair clipped or singed.

6. Poor udder sanitation procedures or excessive water use to wash teats. Teats need to be clean, sanitized and dry before milking.

7. Check your bulk tank cooling system. Slow cooling bulk tank or temperature above 40°F. The bulk tank milk temperature should be less than 40°F within two hours of milking and kept below 45°F during milkings.

8. Mastitis infections due to Streptococcus agalactiae can lead to a large number of these bacteria being released in the milk.

Evaluating Milk Quality

• Monitoring the milking procedures, equipment cleaning and milk cooling should go a long way in producing high quality milk that is low in bacteria

How do Pathogens gain access to a farm ?

Replacement calves

trucks

heifer/ cows

birds /pests feed water

visitors

Most

important

sources of

infection

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STANDAR INDONESIA

•SNI 3141.1 :2011

Susu segar bagian.1 : Sapi

•SNI 01 - 3141- 1998

Standar Susu Segar

.

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Konosonoka I.H., et al (2009)

In total:

•159 bulk milk samples;

• 21 water samples;

• 5 manure samples from the four dairy farms were analyzed;

•4 air samples from 2 farms

•311 subclinical and 87 clinical mastitis secretion samples;

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Methods of analyses

Bacteriological examination according to generally

accepted standards:

Total bacterial count: LVS EN ISO 4833:2003

Salmonella spp.: LVS EN ISO 6579:2003

Listeria monocytogenes: LVS EN ISO 11290-1 + A1: 2007

Staphylococcus spp.: LVS EN ISO 6888-1:1999

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Microflora of bulk milk samples I

Isolated

microorganisms

n Bacteriologically

positive samples, n

(%)

Staph. aureus 159 2 (1,2 %)

Clostridium spp. 159 12 (7,5 %)

Bacillus cereus 159 25 (15,7 %)

L. monocytogenes 159 1 (0,6 %)

Salmonella spp. 159 0

Pseudomonas

aeruginosa

159 4 (2,5 %)

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Microflora of bulk milk samples II

Bacillus cereus n Bacteriologically

positive samples, n

n (%)

Vegetative cells

159

16 (10,1 %)

Spores

159

9 (5,6 %)

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Microflora of bulk milk samples III

Isolated

microorganisms

n Bacteriologically positive

samples, n (%)

Staph.

haemolyticus

159 4 (2,4 %)

Bacillus subtilis 159 2 (1,2 %)

Bacillus

licheniformis

159 2 (1,2 %)

Bacillus brevis 159 1 (0,6 %)

Corynebacterium

aquaticum

159 1 (0,6 %)

Streptococcus spp. 159 3 (1,8 %)

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Microflora of bulk milk samples IV

Gram-negative microorganisms: 9,4 % ( n = 159), int.al.

• Pantoea agglomerans,

• Escherichia coli,

• Hafnia alvei,

• Enterobacter cloacae,

• Pseudomonas aeruginosa,

• Aeromonas hydrophila,

• Serratia mercescens

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Microflora of subclinical secretion sample

Isolated bacteria n %

Staphylococcus spp. 229 74,1

Aerococcus spp. and

Micrococcus

spp.associations

35 11,3

Streptococcus spp. 25 8,1

Aerococcus spp. 7 2,2

Bacillus spp. 4 1,3

Fungi 4 1,3

Cytrobacter spp. 3 1,0

Corynebacterium spp. 2 0,7

Non isolated 2 0

Total 311 100,0

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Microflora of clinical secretion samples

Isolated bacteria n %

Staphylococcus spp. 41 48,2

Streptococcus spp. 29 34,1

Aerococcus spp. 2 2,4

Enterobacteriaceae 10 11,8

Aeromonas hydrophila 3 3,5

Non isolated 2 0

Total 87 100,0

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Incidence of contaminated water samples (%) I

13.3

20.0

53.3

80.0

40.0

60.0

0

10

20

30

40

50

60

70

80

Escherichia

coli

Enterococcus

spp.

coliforms

water from water-pipe

milking system rinsingwater

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13.3

20.0

6.6

20.0

13.3

60.0

0

10

20

30

40

50

60

Bacillus cereus

spores

Clostridium

spp. spores

Moulds

water from water pipe

milk system rinsing water

Incidence of contaminated water samples (%) II

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Microflora from air in dairy farms

Sample from

Cfu/ 9 cm2/ 10 minutes

Nutrient

agar

MacConkey agar Baird Parker agar

Cowshed

before

morning

milking

2100 720

E.coli, Klebsiella spp.,

Enterobacter cloacaea,

Enterobacter aerogenes

2600

Staphylococcus spp.

Milking

room during

milking

process

500 65

E.coli,

Enterobacter spp.

1600

Staphylococcus spp.

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Microflora from cows’ manure (n=5)

Cfu g-1

Contaminated samples,

%

Mesophilic

E.coli

Thermophilic

E.coli

Entero-

coccus

spp.

Coli-

forms

Bacillus

cereus

Listeria

spp.

Salmo-

nella

spp.

1256800

1047600

256600

1018000

100,0 %

100,0 %

20,0 %

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CONCLUSIONS I

•Food born pathogens Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes were isolated from 15,7 %, 1,2 %, 0,6 % bulk milk samples, respectively.

•Salmonella spp. had not been isolated from milk samples.

•Subclinically and clinically diseased cows’ milk is the source for raw milk contamination with Staphylococcus spp., Streptococcus spp. and gram- negative bacteria.

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CONCLUSIONS II

•Water used in dairy farms is the source for raw milk contamination with Escherichia coli, Enterococcus spp., Bacillus cereus, Clostridium spp. and coliform bacteria.

•Air in dairy farms may be source of contamination with members of Staphylococcus genus.

•Manure is the potential source for raw milk contamination with Bacillus cereus, Listeria spp., Escherichia coli.

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Five major parameters are routinely

checked by regulatory agencies for

quality raw milk production

1. Nutritional constituents in milk.

2. Somatic cell counts as related to mastitis.

3. Bacteria counts as related to sanitary practices.

4. Adulteration and pesticide residue contents.

5. Flavor, taste, appearance and temperature.

Quality of Raw Milk tested by

Individual Dairy Processing Plants

1. Standard plate count (SPC) 2. Direct microscopic count (DMC) 3. Freezing point determination (Cryoscope) 4. Presence of inhibitory substances (antibiotic screening test) 5. Sensory evaluation 6. Preliminary incubation (PI) – SPC 7. Direct microscopic somatic cell count (DMSCC) 8. Acid degree value (ADV) 9. Laboratory pasteurization count (LPC) 10. Thermoduric spore count 11. Fat content 12. Total solids content (can also include protein content) 13. Sediment test

Metode pengujian susu segar SNI 01-2780 -1992

Jenis-jenis pengujian

1. Berat jenis 2. Pengukuran kadar lemak dengan metode Gerber 3. Uji protein metode Kjeldahl 4. Uji warna, rasa, bau dan kekentalan 5. Uji keasaman 6. Uji alkohol 7. Uji katalase 8. Penentuan titik beku 9. Pengukuran angka refraksi metode Ackermann 10. Uji reduktase 11. Dan lain-lain samapi 18 jenis uji

THANK YOU !

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milk hygiene and evaluating milk quality - student...

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