Antibiotic Residue Methodology, Withdrawal Times and Incidences.

Dr. Steve Larsen

Director, Pork Safety

January 14, 2014

Outline

• FSIS Testing• Cull Sow Penicillin Research• National Residue Program Changes• Incidences• Fact Sheets• Questions

FSIS Testing

From the Beginning• FSIS Changed Screening Test – 2011 for 2012– FAST to KIS

• Changed– Confirmed by HPLC MS/MS

• Increased KIS and Violative Positives– Penicillin for Sows– Penicillin = Zero Tolerance – Chasing Zero

• Need Withdrawal Research– Penicillin/Sows

Cull Sow Penicillin Research

The Questions• Labeled Use– 1cc/100 lbs.– 7 day withdrawal period– 10cc per Injection Site

• Typical Use– Extra-Label– 5cc/100 lbs.– Extended Withdrawal – 14 days– 20cc per Injection Site

Research Study

• Protocol– Injection Site Volume• 10cc vs. 20cc

– Injection Site Location• Single vs. Multiple

– Withdrawal Days• 7 to 40

• Screen with KIS• Verify with HPLC MS/MS

Preliminary Information

• Limit of 10 mls of an injectable antimicrobial product in one site

• Separate injection sites by at least 3 inches when multiple injections must be given to deliver the appropriate dose

• Separate injection sites by at least 3 inches from the previous day’s injection site when multiple-day therapy is needed

Bottom Line….

• Penicillin Research – ARS– Extra-Label Dosage– 51 day withdrawal – kidneys– For Zero Tolerance

Change Is In The Air at FSIS – 2012

Comparison: Old vs. New

• OLD METHOD• Scheduled sampling

(exposure assessment) • Inspector-generated

sampling• Import sampling• 300 Samples/Class

• NEW METHOD• Tier 1 (exposure

assessment)• Tier 2 Inspector-

generated sampling• Tier 3 (targeted

herd/flock testing)• Import sampling• 1 Sample/Multiple Tests

National Residue Program

Important Differences

•Inspector Generated Tests – Sows– KIS

•Multi-Residue Method – MRM– Antibiotics, Sulfonamindes, Anti-inflammatories, β-

agonists, and Steroids

FSIS Methodology – Penicillin Sow Example

• Screen Kidney with KIS• Positive Kidney Test– Generic Positive, could be anything

• Send Kidney, Muscle and Liver to FSIS Lab– Carcass and Tissues Are Held Until Results– Run Multi-Residue Methodology Plate, Kidney First• 52 Analytes• Positive for Penicillin, run Muscle

– Confirm with HPLC MS/MS• Zero Tolerance, so any amount is violative

Methodology

• If:– Kidney and Muscle are violative, all get tanked– Kidney violative and Muscle non-violative, Kidneys

tanked and carcass can pass– Kidney and Muscle are non-violative, all are okay

• Process from screening test to confirmation?– About 4 to 5 days

• Issue for pre-rigor sow plants/sausage makers• Traceability issues, Consolidators

Next Steps - Working with NPPC and AASV• Establish a tolerance in edible tissue – FDA

– Other Commodities have 50 ppm– Reduce withdrawal to 47 days

• Establish a Higher Tolerance than 50 ppm – FDA– Highly unlikely due to:

• Cost• Daily Intake – allergenicity issues

• Declare Sow Kidneys as inedible tissue – FSIS/Packer– Would help violations– Muscle withdrawal at 12 days

Now What?

• 51 or 47 Day Withdrawal is Not Practical– Alternatives Are More Expensive and Closer to Human

Antimicrobials

• Alternatives– PolyFlex – Ampicillin

• Ampicillin– Established MRL– Extra-Label usage – Approve in Canada but not U.S.– Research to Find Withdrawal Time

Incidences of Residues

What Animals Are Tested?

• Boars/Stags• Market Hogs• Roaster Pigs• Sows

• Let’s focus on the New Method!

April – June 2013• Boars/Stags– None

• Market Hogs– 3 Penicillin– 1 Sulfamethazine

• Roaster Pigs– None

• Sows– 45 Penicillin– 3 Sulfamethazine– 1 Gentamycin Sulfate

July – September 2013• Boars/Stags– None

• Market Hogs– 1 Penicillin

• Roaster Pigs– None

• Sows– 19 Penicillin– 2 Zearalanol– 1 Ampicillin– 1 Desfuroylceftiofur

Information Sheets

Questions?