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Flashcards in Milk And Dairy Production Deck (31)
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Define milk

- normal mammary secretion of milking animals
- it hour either addition to or extraction from it
- intended for consumption as liquid milk or further processing


Define raw milk

- milk that has not been heated beyond 40* or undergone any Tx that has an equivalent effect


Define milk product

- product obtained by any processing of milk which may contain food additives and other ingredients functionally necessary for processing


How does per capita consumption of milk butter and cheese differ around the world?

- different countries in different heirachy for consumption of milk (UK top) but not top creams and cheese


How has whole milk consumption changed over 10 years?

Decreased massively in UK
- China 5% increase in a year
- India 3% increase in a year!!


What market trends will affect dairy consumption in the future?

- Asian markets will govern dairy production
- massive ^ people >65yrs will affect habits of consumption


How ha world milk production changed over 10 yrs

Increased (despite Uk demand decreasing, other markets governing)


What happened with milk production 2014/15?

Massive increase in production
- probably because of high prices of milk 2013/14


Largest milk producers in the world

- US
- India
- China
- Brazil
- Germany
- Russia
- France
- NZ
- Turkey
- UK 10th


Chemical composition of milk

> water
> fat (lipids)
> solids (not fat)
- 3% protein
-4% lactose
- minerals
- acids
- enzymes
- vitamins
> cheese more saturated fat
> yogurt more probiotics


Why is milk consumption controversial?

- complex
- don't look at individual studies, all conflicting


Average milk production per cow per year

- 2004: 6,700
- 2014: 7,900


Milk production chain

- mostly milk production within UK and consumed in UK
- mostly from dairy (tiny beef)
- some consume on farm, majority divide half and half liquid consumption and production purposes


Is consumption of raw milk legal?

Illegal Scotland, OK England Wales and Northern Ireland


How does risks of raw milk consumption compare to pastuerised?

- some risks even if pasteurised (40/120 cases)
- raw milk tiny % of milk consumed but double cases of outbreaks (70/120) statistics = 150x risks consuming raw milk


Production requirements for raw milk production

- no signs for dz communicable to humans through milk
- good general health
- no udder wound likely to affect milk
- no unauthorised substances or products administered
- withdrawal periods observed if authorised
- free of brucellosis and TB
- can ONLY be sold DIRECTLY to consumer
- hygiene rules
- health warning on the label
- monitored by inspection 2x a year
- milk sampled and tested quarterly for total bacterial count and coli forms


Which hazards can contaminate milk at pre harvest stage?

- ecoli 0157
- campylobacter
- listeria monocytogenes
- salmonella
- yersinia enterocolitica
> presence is VERY LIKELY


FSAs review of raw milk drinking controls

- risk acceptable when appropriate hygiene levels applied
- except vulnerable groups
- current restriction should remain in place
-risk communication could be improved esp vulnerable groups, changes to labelling require


What is the legal SCC for milk destined for legal market


Define the processing stages of milk

- filtration (FBs and large particles)
- clarification (remove sediment dust epithelial cells etc)
- decreaming (milk fat totally/partially reduced through centrifuging)
- standardisation (milk contents adjusted)
- heat Tx (pasteurisation or sterilisation)
- homogenisation(decrease size of fat globules decreasing risk of creaming)
- cooling, filling, and storage


Aims of pasteurisation

- decrease public health risk (pathogenic bacteria)
- Improve shelf life and quality (spoilage bacteria)


Outline different forms of pasteurisation

- LTLT : low temp long time (batch, 63* 30 min)
- HTST : high temp short time (continuous 72* 15s or 25s UK)


Why was HTST Pasteurisation extended to 25s in the UK

- to ensure destruction of MAP (Johnes)


How is pasteurisation success tested?

Alkaline phosphatase negative (will be denatured if properly pastuerised)


How is sterilisation different to pasteurisation?

- UHT (ultra high temperature)
> mix steam to indirect heat exchange
- nutritional quality not changed massively (slight v vitamins)
- change in flavour and changes further over time
- sterility has to be maintained (aseptic packaging)


Is milk sterile?

At level of production from mammary gland yes
- contaminated during and after milking and is a good environment for bacteria to survive


What types of bacteria can be involved in milk contamination?

> spoilage
- degrade carbs, fat, proteins, change flavour and texture
- psychotrophic bacteria (like cold?)
- pseudomonas, bacillus, clostridium, lactobacillus, micrococcus, streptococcus
> pathogenic
- e.coli 0157, campy, salmonella, bacillus cereus, listeria, yersinia
- moulds
- can be present d/t failure of technology (eg. Heat tx) or post process contamination
> desirable for further processing
- for yoghurt and cheese


Outline cheese production

- pasteurisation sometimes
- addition of starter culture and rennet
> bacterial fermentation -> lactic acid
> rennet -> coagulation of casein
- cutting
- ripening (specific requirements if made from unpasteurised milk)


Risks of cheese and yoghurt production

- slow decrease in pH (should be rapid drop)


Possible sources of contamination of dairy products

- 1* production (eg. Campy or e.coli raw milk)
- processing environment (listeria in cheese plants)
- equipment or handling people (s. Aureus on people)
- ingredients (fruit in yoghurts)
- transport (ice cream premix contaminated in truck)
- packaging (chemical substances)