Supply Chain View To Prevention Of Antimicrobial Residues In Pork

Consumers and important trade markets value meat without residues of antimicrobials. Preventive actions taken by the vet and the farmer are therefore essential to prevent presence of residues. This includes careful registration of use of antimicrobials, marking of treated animals, and compliance with withdrawal periods. Moreover, surveillance (own check and official samples) is needed to detect enough cases to encourage compliance.

To identify causality, findings of residues in the own check result in a follow-up visit in the herd of origin within few days. Without such a visit, the farmer is not allowed to send pigs to slaughter. However, information about the type of antimicrobial is often not available at the time of the visit, which hampers the possibilities to explain what went wrong.

A new multi-chemical diagnostic method for testing of residues - called HPLC LC-MS/MS – is on the market and is already used in the national monitoring. It has a higher sensitivity, is quicker, but also more expensive than the traditional biological method being used.

We looked into how prevention and surveillance could be further improved.

In 2015, we undertook a trial in 10 sow herds in collaboration with a veterinary practice to evaluate different tools to mark sows. The farmers’ experience with respect to these tools were collected and evaluated.

We used data from the Danish surveillance for residues in pigs covering 18,000 samples annually. To identify indicators for high-risk finishing herds, we collected specific information about findings during 2.5 years - including substances and reasons for presence. This was combined with information from the Danish meat inspection database. Next, we set up a scenario tree to simulate the effect of different future risk-based scenarios.

The surveillance results show a low prevalence - in particular for finishing pigs. For sows, the prevalence is slightly higher, presumably because the slaughter date is unforeseen, which points to a special need for marking of treated sows. Here, the trial showed the usefulness of the new tools, which are cheap and easy to use.

Chronic pleurisy was identified as an indicator for high-risk finishing herds (within-herd prevalence > 40%). By use of that we set up a risk-based own check program.

This program is now being implemented by the largest abattoir company. The sample size will be halved, and more weight will be given to sampling from high-risk herds, resulting in the same number of positive samples and equal costs. The multi-chemical method will be used, which will enable more effective follow-up visits – because information about substance found will be available prior to the visit.

Disclosure of Interest: L. Alban Conflict with: DAFC gives advice to farmers and abattoirs - and I work for them, H. Rugbjerg: None Declared, J. V. Petersen Conflict with: Works for DAFC which is the industry orgainization for farmers and abattoirs, L. R. Nielsen: None Declared.