Calf Antibiotic and Sulfonamide Test (CAST) for Screening Antibiotic and Sulfonamide Residues in Calf Carcasses

Abstract

The Calf Antibiotic and Sulfonamide Test (CAST), a microbial inhibition screening test, was developed for detecting antibiotics and sulfonamides in bob veal calf carcasses. The test uses Bacillus megaterium ATCC 9885 as the indicator organism and Mueller Hinton agar as the growth medium. Compared to Swab Test on Premises (STOP), developed in 1970, this screening test has higher sensitivity and the ability to detect a wider range of veterinary antimicrobial residual drugs, particularly sulfonamides, at lower concentrations. Carcasses that are tested with CAST and suspected of containing chemical residue above tolerance level are retained for confirmation. Disposition of these carcasses are determined upon laboratory result. Routine testing of bob veal calves with CAST allowed the Food Safety and Inspection Service to release most calf carcasses within 24 h post-slaughter, thus conserving shipping and handling resources. However, changes in the regulation in 1990 dictate that disposition of carcasses found to contain violative levels of sulfonamide residues should be based on laboratory findings. The analysis of the data for the years 1990–1994 and 1998 indicate that the use of CAST over the years was significant, and had a direct impact on reduction of residue violations in veal carcasses. With the use of CAST, potentially harmful antimicrobial chemicals entering the human food chain through veal meat have been minimized.

Microbial screening methods for detection of antibiotic residues in slaughter animals

“…The possibility for preliminary identification from activity profiles was also explored for the US Food Safety and Inspection Service (USDA-FSIS) method [ 25 , 26 ]. This method consists of seven test plates and is used by the USDA-FSIS as a microbial confirmatory procedure for samples which tested positive in initial screening tests such as STOP [ 27 ], CAST [ 28 ], and FAST [ 29 ]. The method does not use the commonly applied K. rhizophila ATCC 9341, but uses two erythromycin- or (dihydro)streptomycin-resistant derivatives, which may improve the identification of macrolides and aminoglycosides.…”

Evaluation of three different microbial inhibition tests for the detection of sulphamethazine residues in the edible tissues of rabbit

“…Their sensitivity to sulphonamides were often affected by differences in test media, depth of agar layers, pH value of the agar medium, addition of TMP or dextrose to the agar medium, temperature, preparation and application of the standard solution, animal tissues, etc. (Bogaerts and Wolf 1980;Hrdlička 1990;Heitzman 1994;Koenen-Dierick and De Beer 1998;Okerman and Van Hoof 1998;Okerman et al 1998;Korsrud et al 1998;Hussein 2004;Gaudin et al 2004;Dey et al 2005;Kožárová and Labanská 2005;Janošová et al 2007b;Pikkemaat et al 2008).…”