Dairy products

Dairy products - Dairy products

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LR/CC/FNB Dairy Products Production & Processing
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LR/CC/FNB 1: Dairy products L Based on Milk L Comes from female mammals L mainly cows, also some sheep & goats L 87% water L fat in water emulsion L lipid globules stabilised by casein protein
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LR/CC/FNB Milk ~ Fat in water emulsion
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LR/CC/FNB 2: Dairy farm L Milking, obtaining milk from the cow L Originally manual, now fully automated L Milk always handled in stainless steel containers L Milk contains a lipase activated by Fe & Cu L Could cause lipid hydrolysis & develop off- flavours L Traditional milk-pails made of wood
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LR/CC/FNB
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LR/CC/FNB
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LR/CC/FNB 3: Whole Milk L Fresh milk, Raw Milk? L Clarified L centrifugal separator L removes sediment, cells, solids particles L Homogenised to give uniform globules L fat globules originally 0.1 to 20 µm diameter L larger globules will float and clump L milk pumped under pressure to shear globules L milk whiter and more stable
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LR/CC/FNB
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LR/CC/FNB 4: Pasteurisation L Microbial contamination of milk common L raw milk, 300,000 bacterial counts per ml L 1860 Louis Pasteur, discovered effect of bacteria L Pasteurisation, batch method, 63°C for 30 min L reduce bacterial counts to below 20,000 per ml
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LR/CC/FNB 5: HTST L High temperature short time, L HTST, 72°C / 15s 88°C / 1s [or 90°/ 0.5s] L Uses plate-heat exchanger L Also kills Mycobacterium tubercolosis y Less effect on milk flavour and quality L Requires the use of an enzyme Alkaline phosphatase naturally present in raw milk to test for adequate treatment
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LR/CC/FNB PLATE HEAT EXCHANGER
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LR/CC/FNB Denaturation of alkaline phosphatase by heat treatment 50 60 70 80 90 100 Temperature °C 0.01 0.1 1 10 100 Minutes Alkaline Phosphatase Active Alkaline Phosphatase Inactivated
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LR/CC/FNB 6: Sterilised Milk L Ultra High Temperature L UHT, 150°C 3 s.
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This note was uploaded on 07/04/2011 for the course BIO microbiolo taught by Professor Point during the Spring '09 term at HKU.

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Dairy products - Dairy products

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