Role of Microbes in Dairy Industary
Role of Microbes in Dairy Industary
Role of Microbes in Dairy Industary
Presented By
Shubham Dwivedi Megha Mazumdar Sangita 1 Amit Kumar Sharma
Introduction
Milk: the first food for young mammals Provides high quality protein, vitamins and minerals and is a source of energy Worldwide many mammalian species are used to produce milk and milk products Example Goats, sheep, horses, yaks However, our focus will be on milk from dairy cows
Fluid Milk
Colloidal dispersion of the protein caesin and the whey proteins. It is an emulsion with fat globules suspended in the water phase Composed mainly of water 87-89% Milk solids make up the other 12-13% Solids include the carbohydrates, lactose, fat, protein and minerals Solids-not-fat Excludes the fat and includes the caesin, whey, lactose, proteins, minerals
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Staphylococcus aureus
Clostridium
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Listeria Monocytogenes
Soil, dust, mud and animals Can multiply at refrigeration temperatures Can cause meningitis and septicaemia
Salmonella
Over 2000 types Cows, poultry, pigs
Escherichia coli
Rare, infective dose 10 cells Faecal material into milk
Clostridium perfringens
Environment, human and animal intestines Ingestion of large numbers cause illness
Hygiene procedures
Daily cleaning of milking apparatus Farmer washing hands / wearing gloves
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Temperature
Tested on arrival
Below 5C
Organisms and temperature influence bacterial proliferation
Number of bacteria per ml after 24 hours
5C 10C 2,600 11,600
12.5C
15.5C 20C
18,800
180,000 450,000
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Mastitis
High level indicates sub clinical mastitis Pathogens Streptococcus Aureus
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No taints
Good compositional quality
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Pasteurisation
Discovered by Louis Pasteur Milk is heated to 60-63oC for at least 15 seconds.
Cooled immediately.
Pasteurisation kills harmful bacteria (Pathogens). Mycobacterium paratuberculosis.
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Pasteurizing
Low Temperature Longer Time (LTLT) Heats milk to at least 145 degrees C for at least 30 minutes Can cause a cooked flavor Not used by some milk plants for fluid milk products High Temperature/Short Time (HTST) Heats milk to at least 161 degrees C for at least 15 seconds Milk is immediately cooled to below 40 degrees C and packaged in plastic jugs or plastic coated cartons
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Homogenization
Prevents the cream from rising to the top A homogenizer forces milk under high pressure through a valve that breaks up butterfat globules to such a small size that they will not coalesce (stick together) Does not affect the nutrion or quality
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Beverage Milk
Most raw milk fat content is 4% or higher Most beverage milk is 3.4%
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Nutritional Qualities
Vitamins may be added A & D most often due to their loss A during fat separation and heating D because it is not present in milk Supplemeted in the form of a water-soluble emulsion Many states have milk standards that require the addition of milk solids These represent the natural mineral, protein, and sugar portion of nonfat dry milk
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Quality Control
Numerous test on raw and pasteurized product Microbial organisms are tested by using the standard plate count (SPC) and ropey milk test
Equipment used to analyze butterfat and solids-not-fat is calibrated on a regular basis to ensure consistency
All products have a sell-by date Samples of the products packaged each day are saved to confirm they maintain their freshness 7 days after the sell-by date
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Phosphatase test
To test pasteurisation process efficacy To check no raw milk contamination
Phosphatase is an enzyme
Inactivated by pasteurisation Any remaining phosphatase activity = pasteurisation process not effective
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Friendly Microbes
Milk to curd Milk to cheess Starter cultures added
Bacteria
Lactose Lactic Acid
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Bacteria in Yogurt
Lactobacillus bulgaricus Streptococcus thermophilus
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Others:
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Conclusion
Pathogens who effect milk quality Source of Milk Effect of Human Life Milk Quality
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