肉鸡屠宰加工中减菌处理前后细菌菌相分析

基于16S r DNA V6~V8可变区的聚合酶链式反应-变性梯度凝胶电泳(polymerase chain reaction-denaturing gradient gel electrophoresis,PCR-DGGE)技术分析肉鸡屠宰加工过程中减菌处理前后胴体或产品细菌多样性。在预冷环节前采用50℃、1.5%乳酸溶液对肉鸡胴体冲淋15 s进行减菌处理,采集屠宰加工环节中减菌处理前后的胴体或分割产品表面样品,提取样品中的细菌总DNA,通过16S r DNA V6~V8可变区的PCR扩增,变性梯度凝胶电泳,对PCR扩增片段割胶回收、克隆测序分析减菌前后细菌菌相变化。结果表明,减菌前,胴体清洗环节DGGE条带的数量最多、亮度最强,细菌污染最严重,其次是分割环节,而预冷环节细菌种类及数量最少,污染程度最低;减菌后,各屠宰加工环节细菌种类与数量较减菌前均有所减少,其中胴体清洗环节与分割环节细菌的种类与数量减少量最多,预冷环节细菌的种类及数量最少,不同屠宰加工环节细菌种类并不完全一致;乳杆菌属细菌在整个肉鸡屠宰加工过程中均有出现,与肠杆菌科和假单胞菌属细菌为肉鸡屠宰加工过程中的优势腐败菌。

Bacterial Flora before and after Bacterial Reduction during Slaughtering and Processing Broiler Chickens

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.