Milk SDL

Question 1

What are some main pathogens that could be present in milk and dairy products?

Answer 1

Pathogens include Salmonella spp., Campylobacter spp., E. coli, Listeria monocytogenes, Brucella, and Mycobacterium bovis.

Question 2

Why is milk considered a potentially hazardous food product?

Answer 2

Milk can harbor organisms harmful to human health, which may be transmitted if milk is consumed raw or improperly processed.

Question 3

What are key requirements for hygienic practices in primary milk production?

Answer 3

Clean animals, well-maintained facilities, pest control, isolation areas, and restrictions on housing incompatible animals like pigs and poultry near milking cows.

Question 4

Describe the steps involved in circulation cleaning of the milking plant.

Answer 4

Warm rinse, hot wash cycle with alkaline detergent, followed by a cold rinse.

Question 5

What is used to remove milk fat residue from the milking plant to prevent increased bacterial counts?

Answer 5

An alkaline wash.

Question 6

What is the purpose of an Acid Boil Wash (ABW) at 96°C in the cleaning process?

Answer 6

To remove mineral deposits, also known as “milk stone.”

Question 7

How much water is required per milking unit for an effective wash cycle?

Answer 7

Between 10 and 20 liters.

Question 8

What are potential consequences of skipping pre-milking routines?

Answer 8

Increased risk of clinical mastitis, high bacterial counts in milk, missed oxytocin release leading to inefficient milk harvesting, and development of teat-end hyperkeratosis.

Question 9

What does a high Total Bacterial Count (TBC) or Bactoscan indicate?

Answer 9

It suggests poor milking hygiene, inadequate plant cleaning, or high bacterial shedding from cows.

Question 10

What does an increased coliform count in bulk milk often signify?

Answer 10

Inadequate teat preparation and disinfection before milking, as coliforms are often environmental contaminants.

Question 11

What are common sources of contamination identified by hygiene scoring of dairy cows?

Answer 11

Dirty legs (faecal splashing), dirty tails (small cubicles or loose faeces), dirty flanks (poor bedding management), and dirty udders (general contamination sources).

Question 12

How can a vet contribute to ensuring high milk quality on a dairy farm?

Answer 12

By advising on cow cleanliness, using hygiene scoring systems, and analyzing milk quality data like Bactoscan and TBC to identify sources of contamination.

Question 13

What are the main stages of the dairy supply chain?

Answer 13

Primary production, collection, standardisation, pasteurisation, processing, and distribution.

Question 14

How many dairy producers are currently in the UK?

Answer 14

Approximately 8,000.

Question 15

What is the average size of a dairy herd in the UK?

Answer 15

Around 140 to 150 cows.

Question 16

How much milk is produced annually in the UK?

Answer 16

Over 14 billion liters.

Question 17

What proportion of UK milk production is consumed as liquid milk?

Answer 17

About 40%.

Question 18

What is High Temperature Short Time (HTST) pasteurisation?

Answer 18

Heating milk to 71.7ºC for 15 seconds followed by immediate cooling.

Question 19

How is the pasteurisation process verified for safety?

Answer 19

By testing for alkaline phosphatase (ALP) activity; pasteurised milk should be ALP negative.

Question 20

What are the main effects of pasteurisation on milk?

Answer 20

Kills harmful pathogens, slightly reduces vitamin C and some B vitamins, and disaggregates fat globules.

Question 21

What pathogens are specifically targeted by pasteurisation?

Answer 21

Mycobacterium tuberculosis and others, although some concern remains about Mycobacterium avium paratuberculosis (MAP).

Question 22

What are the main food safety risks associated with raw milk?

Answer 22

Potential exposure to pathogens like Salmonella spp., Listeria spp., and Mycobacterium tuberculosis.

Question 23

What are the key differences in hygiene standards between raw milk and heat-treated milk?

Answer 23

Raw milk must be tested and free from pathogens like Salmonella spp., while heat-treated milk undergoes pasteurisation or UHT to reduce microbial load.

Question 24

What are the risks versus benefits of consuming raw milk?

Answer 24

Risks include exposure to zoonotic diseases; benefits are mostly anecdotal, such as taste and unproven health claims.

Question 25

What are potential problems in milk processing at the reception and storage stages?

Answer 25

Contamination, improper cooling, and bacterial growth.

Question 26

What are the critical control points in milk processing?

Answer 26

Pasteurisation, proper holding temperatures, and contamination prevention during bottling.