Submitted to: Journal of Meat Focus International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 1996
Publication Date: N/A
Interpretive Summary: Chicken carcasses are routinely passed through two cold water baths as the final stages of processing to lower the carcass temperature thereby inhibiting the growth of bacteria. Prior research has shown a washing effect which lowers the bacterial counts but increases cross-contamination with other bacteria. The objective of this research was to apply air injection & a low concentration of acetic acid to the chilling operation to reduce bacterial counts, limit cross-contamination, & test the effect on appearance & sensory characteristics. Acetic acid, a generally recognized as safe (GRAS) chemical was added to the chiller water with & without air injection. Total aerobes were not affected but Enterobacteriaceae & salmonellae incidence were significantly lowered by the treatments. Appearance was altered by darkening the skin of treated carcasses while sensory characteristics were not affected. The use of one or a combination of these treatments should result in a safer product reaching the consumer without altering the taste or smell of the cooked product.
Technical Abstract: Broiler carcasses were subjected to a 30 min prechill treatment with & without air injection & food grade acetic acid at a concentration of .6%. After treatment the carcasses were monitored for visual appearance, moisture pickup, & microbiological quality. Color change & skin appearance were subjectively monitored. Microbiological quality was determined using the low volume whole carcass rinse & salmonellae incidence of inoculated carcasses. In a separate experiment using the same treatment protocol, treated carcasses were chilled in an ice slush for 30 min & held overnight at 2 C. The breast muscles were removed & cooked by two methods. Triangle tests to determine sensory differences due to acetic acid were conducted. The skin color of treated carcasses turned a light yellow, & the feather follicles were protruded or puckered. Moisture pickup was lowest for the control, air with acid, & acid treatments (5.02, 5.53,& 5.06%, respectively). Total aerobic counts were not affected by any of the treatments, but Enterobacteriaceae (ENT) counts of treated carcasses were significantly lower than the counts for the water control carcasses. Log10 ENT counts ranged from 5.52 for the control to 2.93 for the carcasses treated with air & acetic acid. Salmonellae incidence was highest for the control carcasses (96%) & lowest for the air plus acid treatment (8%). Based on sensory triangle tests using a trained panel, there were no statistically significant differences in the samples from either cooking method.