Pasteurization of milk is done at a temperature of
(B) 63degC for 30 min[?]PasteurizationoOriginally designed to eliminate Mycobacterium tuberculosis, Coxiella burnettioInitially 63degC for 30 minutesoHigh-temperature short-time pasteurization (HTST)-Kills pathogens-Lowers bacterial numbers, milk keeps while refrigeratedoUltra-high-temperature pasteurization (UHT)-Milk can be stored with no refrigeration-Super heated steam (temperature goes 74degC to 140deg to 74deg in 5 seconds)oPasteurization used to reduce microbial numbers in milk and other beverages while retaining flavor and food quality of the beverage.oFlash pasteurization (high-temperature short term pasteurization) quick heating to about 72degC for 15 seconds, then rapid cooling.[?]Pasteurization of milk:-Holder (Vat) method: Milk is kept at 63-66degC for at least 30 minutes & then quickly cooled to 5degC. Vat method is recommended for small & rural communities.-High Temperature & Short time (HTST) Method: Milk is rapidly heated to a temperature of nearly 72degC is held at that temperature for not less than 15 seconds & is then rapidly cooled to 4degC.-Ultra-high Temperature (UHT) Method: Milk is rapidly heated usually in 2 stages (the second stage usually being under pressure) to 125degC for a few seconds only. It is then rapidly cooled and bottled as quickly as possible.-Kills and removes all pathogens (100%)-Kills most non-pathogens (99%)-Surviving organisms are spore formers, thermoduric and thermophilic organisms.[?]Milk-borne diseases:oJoint FAO/WHO Expert Committee (1970) on Milk Hygiene classified milk-borne diseases asoInfections of Animals that can be transmitted to man:oPrimary Importance:-Brucellosis-Streptococcal infections-Staphylococcal enterotoxin poisoning-Salmonellosis-Q feveroLesser Importance:-Cow-pox-Foot & mouth-Anthrax-Leptospirosis-Tick-borne encephalitisoInfections primary to man that can be transmitted through milk:-Typhoid & paratyphoid fevers-Shigellosis-Cholera-Enteropathogenic Escherichia coli (EEC)-Non-diarrhoeal diseases-Streptococcal infections-Staphylococcal food poisoning-Diphtheria-Tuberculosis; Enteroviruses; Viral hepatitisoMethylene blue reduction test: It is an indirect method for detection of microorganisms in mil. The test is carried out on the milk accepted for pasteurization.oPasteurization kills nearly 9% of the bacteria in milk including the more heat-resistant tubercle bacillus & the Q fever organisms. But it will not kill thermoduric bacteria nor the bacterial spores.oDespite pasteurization, with subsequent rise in temperature, the bacteria are bound to multiply. In order to check the growth of microorganisms, pasteurized milk is rapidly cooled to 4degC.
73degC for 20 min
63degC for 30 min
72degC for 30 seconds
63degC for 30 seconds
Nutrition and Health