Abstract:

The bacterial diversity of carcasses or products of broiler chickens before and after bacterial reduction during
slaughter and processing was analyzed by polymerase chain reaction (PCR) amplification and denaturing gradient gel
electrophoresis (DGGE) based on the V6–V8 variable regions of 16S rDNA. Broiler carcasses were rinsed with 1.5% lactic
acid solution at 50 ℃ for 15 s for reducing bacteria before the pre-cooling treatment. Bacterial total DNA was extracted
from the samples collected from the surface of carcasses or carcass parts before and after bacterial reduction during
chicken slaughter and processing and the V6–V8 regions of 16S rDNA were amplified by PCR using a universal primer. The
bacterial community structure was analyzed by DGGE. The results showed that the largest number of bands with the highest
brightness in the DGGE profile was observed during carcass cleaning before bacterial reduction, indicating the most serious
bacterial contamination, followed in turn by carcass segmentation and pre-cooling where the lowest bacterial count and the
smallest number of bacterial species were obtained suggesting minimum bacterial contamination. After bacterial bacteria,
both the total bacterial count and the number of bacterial species were reduced during slaughtering and processing, as
compared with those observed before bacterial bacteria. The largest reduction in the two parameters was found during both
carcass cleaning and segmentation, and the smallest reduction during the pre-cooling stage. The bacterial species were not
entirely consistent during the slaughter and processing of broilers, and Lactobacillus was found throughout the entire process
as the predominant spoilage bacteria together with Pseudomonas sp. and Enterobacteriaceae.

Key words: PCR-DGGE, chickens, slaughter, bacterial reduction, bacterial microflora