Differentiation between fresh and thawed meat by an enzyme profile test.

Exudates from fresh (stored at +4°C) and thawed pork and beef (frozen and stored below -20°C) was assayed by the rapid test kit API-ZYM(TM) to determine enzyme profiles. The test kit consists of 20 wells for different enzyme substrates. Of altogether 1040 results, only few reactions of the enzymes differed in their intensity between frozen and thawed pork or beef. Fresh pork showed a more intensive β-galactosidase and N-acetyl-β-glucosaminidase reaction while with fresh beef a more intensive reaction could only be detected for N-acetyl-β-glucosaminidase. Only N-acetyl-β-glucosaminidase showed significant differences between fresh and frozen meat in both species (α = 0·01). Considering the indistinct results of the test kit differentiation between frozen and thawed meat, the API-ZYM(TM) test kit is considered not suitable for distinguishing frozen from thawed pork or beef.