Abstract
The study aimed to evaluate the effect of chilling methods and their related process steps (scalding, de-feathering, evisceration, and chilling) on chicken bacterial load in poultry processing plants in Khartoum State during the period from November 2019 to May 2020. Immersion and air chilling methods were both investigated in eight poultry slaughterhouses, four slaughterhouses for each method. Both checklist and microbiological tests were used in the evaluation. A total of 160 samples were collected from 32 carcasses, four carcasses were taken after each process step, from five parts of broiler carcasses (wings, legs, thigh, breast and backbone) and all these samples were examined bacteriologically. The samples were subjected to the total bacterial count and isolation of Enterobacteriacea and E. coli. The result revealed that the mean bacterial load count of legs samples was highly significantly greater in emersion method (2.1±.05) compared to air chilling method (.7±.1), p=.000. Also, the result indicates highly significant differences between the two chilling methods with regard to E. coli+Salomnella and E. coli+Enterobacter (.000), E. coli+Shigella (.001), E. coli+Citrobacter (.000). When comparing the chilling methods with their respective process steps, scalding process showed no significant difference between the two chilling methods. Concerning scalding water change during each shift, all slaughterhouses (100%) were not changing scalding water. Washing process step revealed no significant differences between the two chilling methods in terms of in and out washing of carcasses, P.214 and .500, respectively. For chiller temperature all plants using air chilling practiced optimal temperature (4°C or less), while three quarters (75%) of plants using immersion chilling exceeded the acceptable limit but there were no significant differences between the two chilling methods, with p>0.071. In conclusion the microbial contamination of poultry meat in slaughterhouses in Khartoum State was higher in emersion chilling method compared to air chilling method.