Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 19, 2000
Publication Date: N/A
Interpretive Summary: Temperature has long been known to be a primary factor in preserving the safety and quality of poultry and meat products. In this study, the effect of different refrigeration and freezer temperatures and combinations on Salmonella and different indicator organisms were systematically studied. It was conclusively shown that the human pathogenic bacteria Salmonella was not killed by freezing temperatures but that it would not grow at refrigeration temperatures. Spoilage organisms were shown to grow slowly at refrigeration temperatures as low as 26 F. No matter the initial storage temperature, when chicken is frozen at 0 F, the types and level of bacteria present does not change appreciably.
Technical Abstract: To determine the effect of different refrigeration and freezer temperatures on the microbiological profile of chicken, fifty commercially processed broiler chickens were each split in half on the day of processing. Equal groups were held at 4, 0, -4, -12 and 18øC (40, 32, 26, 10, and 0ø F), respectively for 7 d. One half of each group was then transferred to a 0ø F holding chamber for an additional 7 d. Carcass halves were rinse sampled and the diluent sampled for mesophilic, psychrotropic, coliform, and salmonellae counts after the initial 7 days at different temperatures and after 7 additional days at -18ø C. Ten carcass halves were sampled on the day of processing to give baseline counts. Meosphilic bacteria counts/mL were about Log 4.6 on day 0, increased by 2 Log after 7 d on carcasses held at 4ø C, and were unchanged at all other storage temperatures. Psychrophilic counts/mL were about Log 3.6 on day 0 and increased during the initial 7 d by about 3.9, 1.9, and 1.4 Logs, respectively on carcasses held at 4, 0, and-4ø C, and had less than 1 Log increase at 10 and 0ø F. Coliform counts were about Log 2.2/mL on day 0 and had declined to about Log 1.5/mL or less by day 7 for all storage temperatures. E. coli counts/mL were about Log 2 on day 0 and were reduced about 1 Log or more at other storage temperatures. Salmonellae counts were about Log 1.5 on salmonellae positive carcasses and did not change appreciably at any storage temperature. No counts for any organism significantly changed after placement at 0ø F.