CowSide II is a 3 hour qualitative test of raw milk for inhibitory substances including residues of antibiotics. The method meets Belgian FASFC acceptance criteria for detection capability allowing use at milk control stations. The test was evaluated visually using multiple brands of dry well incubators for vials: a 4 place and 20 place incubator manufactured by Charm Sciences Inc., and a 10 place Delvo® incubator supplied by DSM used by many farmers in EU and USA.
“The Charm CowSide II test is a broad-spectrum inhibition test typically used for the screening of raw commingled, pasteurized, and ultra-pasteurized cow milk,” said Ingrid Huntley, Global Technical Services Specialist for Charm Sciences. “It detects all major classes of antibiotics: beta-lactams, sulfonamides, tetracyclines, macrolides, and aminoglycosides. Eleven drugs are detected at or below US target levels and 30 drugs at or below EU MRLs. This approval will have a significant, positive impact in the EU marketplace by providing another tool for simple drug residue screening at the farm level.”
CowSide II kits consist of single service vials that contain pre-measured bacterial spores, media, and pH indicator. The starting color in the vial is blue/purple. Milk is added to the vial and incubated. If antibiotics are absent, spores germinate and grow, which changes the color to yellow or yellow/green. If antibiotics are present in the milk, microbial growth is inhibited and the positive sample remains blue/purple.