The influence of thawing and marination methods on the bacteriological quality of frozen broiler’s meat

Abstract

This study was designed to investigate the effect of different thawing methods and marination ingredients on the bacteriological quality of frozen chicken broiler carcasses. Therefore, this study was divided into 2 parts the first part: collection of whole frozen chicken broiler carcasses samples and exposing them to different thawing methods (refrigerator, counter top and microwave). While, 2nd part of this study was collection of whole frozen broiler chicken carcasses samples, thawed in refrigerator then treated with different marination ingredient (standard marinade only; M1, standard marinade incorporated with 1% dried rosemary powder; M2 or 1% green papaya fruit powder; M3) plus the control unmarinated samples (C). All thawed and marinated samples were subjected to bacteriological exanimation and antibiotics sensitivity test for the isolated strains. The results revealed that the lowest total aerobic mesophilic bacterial count, Staph. aureus and Coliforms counts were recorded in samples thawed in microwave. However the highest Staph. aureus and Coliforms counts were observed in samples thawed over the counter top. The significant reduction of total mesophilic bacterial count and total Coliforms count were recorded in all marinated samples as compared with control untreated one and the lowest bacterial count was observed in M2 followed by M3. Staph. aureus, E. coli poly2:O125, E. coli poly2:O44 and S. Kentucky were isolated only from samples thawed over the counter top with incidence of 20%, 6.67%, 13.33% and 6.67%, respectively. Staph. aureus was isolated with incidence of 20%, 20%, 6.67% and 6.67% and E. coli poly2:O125 with incidence of 6.67%, 6.67%, 0% and 6.67% from C, M1, M2 and M3, respectively. However, Salmonella strain failed to be isolated from all marinated and control unmarinated samples. All isolated strains from thawed and marinated samples were resistant to amoxcycillin and sensitive to fosfomycin. In conclusion it is recommended to use microwave for thawing of frozen poultry carcasses followed by the use of refrigerator however, thawing over counter top method is inappropriate method which affects safety and quality of thawed meat. Moreover, incorporation of 1% dried rosemary powder and 1% green papaya fruit powder into the standard marinade could improve the bacterial aspect of the marinated chicken carcasses.