Microbiological conditions of moisture-enhanced chicken breasts prepared at a poultry packing plant

Brines circulated in equipment for injecting chicken breasts were sampled before meat processing commenced and at times after the beginning of processing up to 60 min. Numbers of bacteria in the brines increased after processing of meat started but were apparently stable by 45 min after processing began, by which time total numbers of aerobes, coliforms, and presumptive listerias from 15 samples were 5.5, 4.5, and 2.9 log CFU/15 ml. respectively. No Escherichia coli were recovered from those samples, but the total number of E. coli recovered after 60 min of processing was 2.7 log CFU/15 ml. The numbers of bacteria in the deep tissues of injected breasts reflected the numbers of bacteria in brines at the times of meat collection (15 to 30 min after the start of processing) and the amount of brine retained by the meat. Mean numbers of aerobes, coliforms, E. coli, and presumptive listerias in the injected meat were about 2.8, 2.6, 0, and 0 log CFU/g, respectively. Numbers of bacteria in the deep tissues of breasts that had been tumbled but not injected with brine were similar to the numbers in injected breasts. Undercooking to 61 degrees C destroyed most bacteria in deep tissues, but single listerias were recovered from 1-g samples of five and three breasts undercooked to 61 and 70 degrees C, respectively. No E. coli were recovered from any fully cooked breast.