A Survey of the Microbial Flora of Ground Beef, Textured Soy Protein and Textured Soy Protein Extended Ground Beef after 3 Days' and 10 Days' Storage at 4 C.

摘要

A survey of the microbial populations of 31 samples of ground beef (GB), textured soy protein (TSP) and TSP extended ground beef (SGB) after 3 days' and 10 days' storage at 4 C was performed. Analyses included aerobic plate count (APC), psychrotrophic plate count (PPC), coliform most probable number (MPN) and plate determinations (CMPN and CPC), Escherichia coli MPN and plate determinations (EMPN and EPC), Staphylococcus aureus MPN (SMPN), fecal streptococci count (FSC), Clostridium perfringens determinations, isolation and identification of gram-positive and gram-negative organisms and screening for enteric virus. Statistical analyses of the enumeration procedures showed significant increases in the total microbial flora after 10 days' storage. PPCs were significantly higher than APCs. CMPNs were significantly higher than CPCs for GB and SGB. The EMPNs were significantly higher than EPC in SGB only. E. coli was the predominant gram-negative isolate from GB and SGB. Few gram-negative organisms were found in TSP. C. perfringens was the predominant gram-positive isolate in GB and SGB while Bacillus sp. predominated in TSP. Salmonella enteriditis ser. worthington was isolated from GB and TSP. These products contained a wide variety of microorganisms, many in large numbers. If properly handled and cooked before consumption, these products should present no public health problems.