Detection of Species Substitution in Raw and Cooked Meats Using Immunoassays

Federal and state laws require that raw and cooked meats be accurately represented as to the species of meat they contain. A total of 806 raw and 96 cooked meat samples collected from Florida retail markets were examined for regulatory control of these products. An agar-gel immunodiffusion method was used for the identification of beef, pork and horse species in uncured raw meats. Enzyme-linked immunosorbent assays were used to identify poultry and sheep in raw meats and all species in cured raw meats and cooked meats. A positive violative sample was reported only if the target extraneous species present exceeded a 1% level. Results indicated that the overall rate of substituted species in both cooked and raw meat samples was 16.6%. Percentage of violation in cooked products was higher than that in raw meats (22.9% versus 15.9%). The undeclared species found in ground beef and veal products included sheep, pork and poultry, in descending order of frequency. The major substituting species found in ground pork, ground turkey and ground lamb, however, was beef. Horse meat was not detected in any sample tested. Intact pieces of raw meat tested were all correctly labeled. The source of substitution/contamination also was investigated and discussed. Current retail practices in meat markets show a significant problem with mixing of undeclared species in ground and comminuted meat products.