Milk SDL Flashcards
What are some main pathogens that could be present in milk and dairy products?
Pathogens include Salmonella spp., Campylobacter spp., E. coli, Listeria monocytogenes, Brucella, and Mycobacterium bovis.
Why is milk considered a potentially hazardous food product?
Milk can harbor organisms harmful to human health, which may be transmitted if milk is consumed raw or improperly processed.
What are key requirements for hygienic practices in primary milk production?
Clean animals, well-maintained facilities, pest control, isolation areas, and restrictions on housing incompatible animals like pigs and poultry near milking cows.
Describe the steps involved in circulation cleaning of the milking plant.
Warm rinse, hot wash cycle with alkaline detergent, followed by a cold rinse.
What is used to remove milk fat residue from the milking plant to prevent increased bacterial counts?
An alkaline wash.
What is the purpose of an Acid Boil Wash (ABW) at 96°C in the cleaning process?
To remove mineral deposits, also known as “milk stone.”
How much water is required per milking unit for an effective wash cycle?
Between 10 and 20 liters.
What are potential consequences of skipping pre-milking routines?
Increased risk of clinical mastitis, high bacterial counts in milk, missed oxytocin release leading to inefficient milk harvesting, and development of teat-end hyperkeratosis.
What does a high Total Bacterial Count (TBC) or Bactoscan indicate?
It suggests poor milking hygiene, inadequate plant cleaning, or high bacterial shedding from cows.
What does an increased coliform count in bulk milk often signify?
Inadequate teat preparation and disinfection before milking, as coliforms are often environmental contaminants.
What are common sources of contamination identified by hygiene scoring of dairy cows?
Dirty legs (faecal splashing), dirty tails (small cubicles or loose faeces), dirty flanks (poor bedding management), and dirty udders (general contamination sources).
How can a vet contribute to ensuring high milk quality on a dairy farm?
By advising on cow cleanliness, using hygiene scoring systems, and analyzing milk quality data like Bactoscan and TBC to identify sources of contamination.
What are the main stages of the dairy supply chain?
Primary production, collection, standardisation, pasteurisation, processing, and distribution.
How many dairy producers are currently in the UK?
Approximately 8,000.
What is the average size of a dairy herd in the UK?
~150 cows.
How much milk is produced annually in the UK?
Over 14 billion liters.
What proportion of UK milk production is consumed as liquid milk?
About 40%.
Describe the process of High Temperature Short Time (HTST) pasteurisation?
Heating milk to 71.7ºC for 15 seconds followed by immediate cooling.
How is the pasteurisation process verified for safety?
By testing for alkaline phosphatase (ALP) activity; pasteurised milk should be ALP negative.
What are the main effects of pasteurisation on milk?
Kills harmful pathogens, slightly reduces vitamin C and some B vitamins, and disaggregates fat globules.
What pathogens are specifically targeted by pasteurisation?
Mycobacterium tuberculosis and others, although some concern remains about Mycobacterium avium paratuberculosis (MAP).
What are the main food safety risks associated with raw milk?
Potential exposure to pathogens like Salmonella spp., Listeria spp., and Mycobacterium tuberculosis.
What are the key differences in hygiene standards between raw milk and heat-treated milk?
Raw milk must be tested and free from pathogens like Salmonella spp., while heat-treated milk undergoes pasteurisation or UHT to reduce microbial load.
What are the risks versus benefits of consuming raw milk?
Risks include exposure to zoonotic diseases; benefits are mostly anecdotal, such as taste and unproven health claims.
What are potential problems in milk processing at the reception and storage stages?
Contamination, improper cooling, and bacterial growth.
What are the critical control points in milk processing?
Pasteurisation, proper holding temperatures, and contamination prevention during bottling.
