Transcript Guidelines for Antibiotic Residue Avoidance

Guidelines for Antibiotic
Residue Avoidance
S. Andrew
University of Connecticut
Why Should We be Concerned
About Residues in Milk?
The goal is to produce a
nutritious, wholesome food
for consumers.
It is essential to maintain and
foster consumer confidence.
Profitability
Human Food Safety Issues
Sensitivity to antibiotics
Immunological response
Bacterial resistance to antibiotics
No link established between
animal use and human pathogen
antibiotic resistance (however,
there is a potential for this to occur)
Antibiotic Residue Defined as:
Detection of antibiotic in milk:
1. at or above the tolerance or safe
concentration for approved drugs, or
2. at any concentration for unapproved
drugs
3. at any concentration for illegal
drugs
Antibiotic Routes of
Administration
Intramammary
Oral
Injectable
Intramuscular
Intravenous
Intrauterine
Feed Additives
Topical
skin
feet
teats
eyes
Major Use of Antibiotics is for
the Treatment of Mastitis
Intramammary
Dry cow and
lactation treatments
Top Five reasons for Residue
Violations
1. Milking a treated dry or lactating
cow
2. Same milking unit for treated and untreated cows
3. One quarter treated, milk from
other three quarters put in tank
4. Unaware that newly purchased
animals were treated
5. Fresh cow milk contained residues
from dry cow treatment
Why do Residues Occur?
Lack of adequate record-keeping
Lack of understanding antibiotic
use
Poor relationship between
producer and veterinarian
Sischo, and coworkers, 1997
Regulation of Antibiotic
Residues in Milk
Milk is regulated at the bulk tank/tanker
truck level.
Pasteurized Milk Ordinance (PMO)
a. under section 6
milk is sampled 4 times during any
consecutive 6 months.
b. Under Appendix N of the PMO
- every tanker truck is screened for
beta-lactam antibiotics beginning
July, 1992
Penicillin
Amoxicillin
Ampicillin
Cloxacillin
Cephaprin
Ceftiofur
- bulk tank also sampled
If the tanker truck sample is:
Positive
Negative
sample re-tested
2x
if positive - traced
back to bulk tank
no further
action
re-tested at
State Lab
Regulatory action $$$
Milk is analyzed for antibiotic
Residues using Qualitative
Tests
The tests used have been evaluated
and accepted by FDA for use with
bulk tank/tanker truck milk.
# of samples tested
% positive
1995
3,219,071
0.101%
1996
3,310,772
0.106%
Smucker, 1997
Therefore, approximately
99.9% of milk tested is
free of antibiotic residues
It appears that we
are winning the race!
However, 3,507
positive loads in 1996
How to Reduce the Risk of
Antibiotic Residue Violations
1. Follow label directions for
approved drugs (treatment regimen
and withdrawal times)
2. Extra-label use of antibiotic
only under veterinarian guidance
3. Identify treated animals and milk
into separate bucket.
How to Reduce the Risk of
Antibiotic Residue Violations
4. Establish a herd health
management program
5. Establish effective record-keeping
6. Education/communication with all
personnel involved with milking
and treating cows and heifers.
How to Reduce the Risk of
Antibiotic Residue Violations
7. Follow the 10-point Milk and Dairy
Beef Quality Assurance Program
# 2 Establish a valid
veterinarian/client/patient relationship
#8 Use antibiotic residue screening
tests for testing treated cow’s milk
At Which Level Should
Milk be Tested?
Bulk Tank/Tanker
Truck
Individual
Cow
Ideally, screening milk from
treated cows before adding
the milk to the bulk tank
is financially advantageous
However,
Many cases of residue violations
are due to accidentally milking
a dry-treated cow or treated cow
Also……..
The screening tests have not
been evaluated by FDA for
use with individual cow’s milk
Major concern is the potential
for increased false - positive
outcomes. Results in dumping
acceptable milk.
The false-positive rate for
screening tests used with
individual cow’ milk
ranged from:
0 % - 83%
Cullor and coworkers, 1994
Andrew and coworkers, 1997
Sischo and Burns, 1993
Screening milk from cows
treated with an antibiotic
following the appropriate
withholding time
Positive result may be due to:
1. Antibiotic present above tolerance
2. Antibiotic present below tolerance
3. False positive outcome
Factors Affecting False-Positive
Rates of Antibiotic Residue
Screening Tests
Factors associated with:
SCREENING TEST MILK _____
- Test storage
- Somatic cells
conditions
- Milk fat and protein
- Operation of test - Milk sample
Steps to Optimize Screening Test
Performance for Individual Cow Milk
1. ESTABLISH AN EFFECTIVE
MASTITIS CONTROL PROGRAM!
2. Follow drug withholding times.
3. Match the test to the drug.
4. Test visually normal milk.
Steps to Optimize Screening Test
Performance for Individual Cow Milk
5. If result is positive, retest.
6. If positive again, check milk quality
and re-test in 24 hours.
7. If positive, send milk sample to milk
processor laboratory for testing.
Summary
Residue Avoidance
Understanding how antibiotic
residues can occur can aid in
residue avoidance
Using residue screening tests
Summary
Residue Avoidance
Establish an effective herd health
program
Education and communication is
essential
Goal!
Producing high quality milk
maintains consumer confidence