禽肉弯曲菌污染分析及冷藏条件下失活动力学特征

摘要

为了解空肠弯曲菌（ Campylobacter jejuni）和结肠弯曲菌（ Campylobacter coli）在浙江省肉鸡产业链中的污染状况，及其冷藏过程中的失活特征。研究采用多重PCR方法对肉鸡养殖、屠宰和销售环节中分别采集的肛拭子、屠宰场环境和鸡肉等样品进行检测，平板计数法对人工污染鸡肉进行活菌数检测，用于失活特征分析。结果显示，采集的样品中，C. jejuni和C. coli的检出率分别为45.3％（182／402）和4.9％（20／402）；其中，养殖环节中的检出率分别为81.2％（65／80）和0，屠宰环节中的检出率分别为30.5％（48／157）和5.1％（8／157），销售环节中的检出率分别为41.8％（69／165）和7.3％（12／165）。在6℃冷藏条件下，鸡肉中的C. jejuni和C. coli失活曲线具有相似的特征，在30 d贮藏期内，lg cfu分别下降了1.98和2.19；其中，0～14 d细菌数量下降速度较快，14～30 d细菌数量下降较为平缓。 Log-logistic模型相比于Weibull模型对2种细菌的失活曲线有较好的拟合性。上述研究表明，肉鸡养殖、屠宰和销售环节中均存在着一定程度的空肠弯曲菌和结肠弯曲菌污染，其中，销售环节中检出率高于屠宰环节；在6℃冷藏条件下，Log-logistic方程作为2种菌的一级预测生长模型具有较好的拟合性。%Campylobacter jejuni and Campylobacter coli contamination were investigated in the poultry industry chain in Zhejiang province and their characteristics of inactivation in the process of cold storage were described. Multiplex PCR was used for detecting the prevalence of C. jejuni and C. coli in poultry farms, slaughtering facilities and mar-kets of Zhejiang province. Samples were collected as environmental swabs from farms and slaughtering facilities, meat from supermarket as well as wet markets. Simultaneously, two different models of best fit for mechanical charac-teristics of inactivation kinetics of C. jejuni and C. coli during the process of refrigeration of chicken meat were also evaluated by plate count method. The prevalence of C. jejuni was found to be 45. 3% (n=182/402) and that of C. coli was 4. 9% (n=20/402). The positive rate of C. jejuni and C. coli in poultry farms, slaughtering facilities and markets were 81. 2%(65/80)and 0, 30. 5% (48/157) and 5. 1% (8/157), 41. 8% (69/165) and 7. 3% (12/165 ) , respectively. Inactivation curves of C. jejuni and C. coli shared similar kinetics. During storage at 6℃ for 30 days, the lg cfu had decreased by 1. 98 for C. jejuni and by 2. 19 for C. coli. The decline in the number of bacteria for the first fourteen days was recorded to be at a faster rate as compared to the next 16 days. Comparison of Log-lo-gistic model and Weibull model for inactivation kinetics revealed that the Log-logistic model gave a better inactivation curve for fitting of C. jejuni and C. coli.