Swab test on premises

Notes STOP = swab test on premises, measures antibiotic residues in the kidney FAST = fast antimicrobial screen test, measures antibiotic and sulfonamide residue in kidney and liver SOS = sulfa-on-site, measures for sulfonamide residues. 

For very rapid on-farm screening of antibiotic residues in animal tissues, the swab test on premises (STOP) has been widely employed (86). This test involves inserting a cotton swab directly into meat tissues, allowing it to absorb tissue fluids. The swab is the removed and placed on a test plate to be incubated with Bacillus subtilis ATCC 6633 spores at 29 C overnight for evidence of inhibition around the swab. 

The calf antibiotic and sulfa test (CAST), the fast antimicrobial screen test (FAST), and the swab test on premises (STOP) are all bacterial inhibition tests developed at the US Department of Agriculture Food Safety and Inspection Services to screen kidneys for antimicrobial drug residues at slaughter (97-101). For CAST and FAST, an incision is made with a knife, whereas for STOP the tissue is macerated with the shaft of the swab. For all three tests, cotton swabs are inserted into kidney tissue to soak up fluids. Swabs are then incubated on inoculated medium with a disc containing an antibiotic standard used to monitor the viability of the organism and its growth inhibition. 

Other tests based on the use of swabs and microbial inhibition assays were developed at the US Department of Agriculture and Food Safety and are widely used in the United States of America and Canada primarily by meat inspection agencies, including the swab test on premises (STOP), calf antibiotic screen test (CAST), and the fast antibiotic screen test (FAST)." 45 -j g STOP assay employs Bacillus subtilis, and the CAST and FAST assays use Bacillus megaterium. However, these tests will not be discussed further in the context of commercially available assays. 

The USDA/FSIS have a number of rapid tests for determining the presence of antimicrobial substances in carcasses or in live animals. The swab test on premises and the live animal swab test are developed for kidney (or liver) and urine samples, respectively, using an inhibition agar plate assay. The sulfa on site test is used on farm or at slaughter plant to screen samples of serum, urine, or feed for sulfadimidine residues. The test is based on TLC and uses well-defined ratios between concentrations of sulfadimidine in serum or urine and in edible tissues... 

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