A survey of microbial levels for incoming raw beef, environmental sources, and ground beef in a red meat processing plant

A microbial survey was performed for a midwestern red meat processing plant that produces retail cuts and ground beef. Samples were obtained from incoming ingredients, beef during processing, finished product, food contact and environmental surfaces, and the air. Aerobic plate count (APC), coliform count (CC), and Escherichia coli count (ECC) were determined for each sample. Product samples (25 g) were taken from beef carcasses, boxed beef, and ground beef. Swab samples (10 cm(2)) were obtained from food surfaces, food contact surfaces, floors, and walls. All samples were plated on aerobic plate count Petrifilm (for APC) and E. coli Petrifilm (for CC and ECC). Average log(10) APC for product samples ranged from 3 cfu g(-1) for retail cuts to nearly 7 cfu g(-1) for boxed beef and the brisket and flank areas of beef carcasses. Average log(10) APC for ground beef samples was 4.6 cfu g(-1). Average log(10) CC for product samples ranged from 1.4-2.3 cfu g(-1). Highest CC was usually obtained from the brisket area of the beef carcass. Average log(10) ECC ranged from < 1-2 cfu g(-1) and ECC was usually highest in finished ground beef. Average surface counts for log(10) APC ranged from < 1 cfu cm(2) on sanitized processing equipment to 5 cfu cm(-2) on processing floors. Coliforms and E. coli were rarely recovered from food contact surfaces or from food surfaces. Airborne log(10) APC was generally low (0.6 cfu m(-3)) except for the carcass receiving area where counts were 2.4 cfu m(-3). The most important factor contributing to source and level of microbial contamination for ground beef and retail cuts was from incoming raw materials obtained from different suppliers of beef. Microbial testing for beef products and the environment is an important fool for identifying and monitoring potential hazards as part of HACCP and GMP program development. (C) 1997 Academic Press Limited.