Milk Residues

Question 1

Give 2 reasons why we do surveillance for residues

Answer 1

Monitor the levels of compliance in a country or region
Take corrective action when regular violations are discovered or when trends occur.

Question 2

Give 3 reasons why residues occur

Answer 2

1. Withdrawal periods not observed or not adequate
2. Higher doses or longer periods of administration than those authorised
3. Illegal or unauthorised drugs used

Question 3

Who are in charge of residue surveillance (x3)

Answer 3

Veterinary Medicines Directorate (VMD)
Veterinary Residues Committee (VRC)
Food Standards Agency (FSA)

Question 4

What does MRL stand for

Answer 4

Maximum residue limit

Question 5

Define Maximum residue limit

Answer 5

The maximum concentration of a residue that is legally permitted or acceptable in or on a food.
Expressed in μg/kg of that food.

Question 6

Define Acceptable Daily Intake (ADI)

Answer 6

An estimate of the amount of a substance, expressed on a bodyweight basis that can be ingested daily over a lifetime without appreciable risk to the consumer.

Question 7

How is the ADI calculated

Answer 7

Estimated by dividing the “No Observable Adverse Effects Limit” by an uncertainty factor to allow for variables

Question 8

The ADI is divided among all edible tissue - true or false

Answer 8

True

Question 9

Define the withdrawal period

Answer 9

The length of time after the end of treatment with a veterinary medicine that must pass so that we can be sure any residues in edible tissues will have depleted to below the MRL.

Question 10

Why are antibiotic residues so important to control

Answer 10

Risk to human health
They can ruin manufacturing processes that require bacteria e.g. yogurt and cheese production

Question 11

Name 4 causes of bulk tank milk test failures

Answer 11

Mechanical failure - leaking valves
Accidental milk transfer
Contamination of recorder jars
Not withholding milk for recommended time

Question 12

Give 4 ways in which dry cows can cause bulk tank failures

Answer 12

Calving early or a short dry period
Prolonged excretion of an antibiotic
Not withholding milk for the correct period (96hr post calving)
Accidentally milking dry cows

Question 13

What test is designed to test bulk tanks for antibiotic residues

Answer 13

Delvotest

Question 14

Describe how the cascade can be used

Answer 14

Where there is no suitable veterinary medicine authorised in your territory for the specific condition in the animal being treated, to avoid unacceptable suffering, vets are permitted to use their clinical judgement to treat animals under their care in accordance with the cascade

Question 15

What things must a vet do when using the cascade

Answer 15

Get informed consent from the owner
Maintain accurate records
Balancing benefits vs risk
Treatment must comply with Recognised Veterinary Practice (RVP)

Question 16

Name the additional conditions that apply to food-producing animals when using the cascade

Answer 16

The pharmacologically active substances contained in the medicine must have an MRL
Make sure substances are allowed for animals producing eggs, milk or safe for human consumption
Vet must specify an appropriate withdrawal period

Question 17

Name the minimum statutory withdrawal periods for eggs/milk, meat, fish meat

Answer 17

Eggs and milk = 7 days
Meat = 28 days
Fish = 500-degree days
The number of days of the withdrawal period is calculated by dividing 500 by the mean temperature of the water in degrees Celsius.

Question 18

Do horses count as food producing animals under the cascade

Answer 18

Depends
A horse can be declared as non-food producing on its passport and treated as non-food producing
If it is not signed off, it has to be treated as food producing

Question 19

There is a minimum withdrawal period set for honey - true or false

Answer 19

false
Vets must set a suitable period to ensure no risk to public health