MILK HYGIENE and Evaluating Milk Quality - Student...
Transcript of MILK HYGIENE and Evaluating Milk Quality - Student...
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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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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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.
Preliminary Incubation
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.
Preliminary Incubation
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
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
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