冷冻饮品加工过程中单核细胞增生李斯特菌污染状况分析

Contamination status of Listeria monocytogenes in the production process of frozen drinks

目的了解湖南省冷冻饮品生产加工过程中单核细胞增生李斯特菌(以下简称单增李斯特菌)污染状况,为食源性疾病预防和控制提供科学依据。方法采集湖南省2家冷冻饮品生产企业的生产加工各个环节的样品,包括食物样品75份(原料类、中间产品、终产品)和非食物样品279份(环境、仪器设备、人员、工具等),参照GB 4789.30-2010中方法进行单增李斯特菌检测,分离菌株采用脉冲场凝胶电泳法(PFGE)进行分子分型。结果两家企业共监测354份样品,检出28株单增李斯特菌,检出率为7.91%,均在非食品样品中检出(检出率10.04%),其中环境样品的检出率最高(16.07%),人员、仪器设备、工具检出率分别为6.35%、6.58%、10.00%;与车间前处理区(0.96%)、整箱包装区相比(4.44%),灌装区检出率较高(12.20%);O企业非食品样品的检出率(13.94%)高于P企业(4.39%)(χ~2=6.815,P=0.009)。PFGE结果显示,O企业分离的23株单增李斯特菌,分为4个型别,其中有82.6%的菌株为同一型别,P企业分离的5株单增李斯特菌,分为2个型别,其中有4株为同一型别。结论两家冷冻饮品企业在生产加工过程中均检出单增李斯特菌,主要存在于车间灌装区的地面与地面接触物中,两企业检出的单增李斯特菌均存在优势型别,提示应加强消毒与监督,预防单增李斯特菌对冷冻饮品污染的潜在风险。

Objective To investigate the contamination status of Listeria monocytogenes { hereinafter referred to as L. monocyto- genes ） in the production process of frozen drinks in Hunan Province so as to provide scientific evidence for prevention and control of foodborne diseases. Methods Seventy-five food samples from food material, intermediate and end products and 279 non-food samples from production environment, equipment, staff and tools were collected from each production process in 2 frozen drink manufactures in Hunan Province. L. monocytogenes was identified in accordance with the test methods specified in GB 4789.30- 2010. And pulsed-field gel electrophoresis { PFGE } was used for molecular typing of L. monocytogenes isolates. Results A total of 354 samples were monitored in the 2 manufactures, and 28 strains of L. monocytogenes were detected, with the detection rate be- ing 7.91%. All the 28 strains were detected in the 279 non-food samples, with the detection rate being 10.04%, of which the de- tection rate of environment samples was the highest （ 16.07% ）, followed by the samples collected from the staff （ 6. 35% ）, appa- ratuses { 6.58% ） and tools { 10.00% ）. The detection rate of L. monocytogenes was higher in filling zones （ 12. 20% } than in pre- treatment （ 0.96% } and packing zones （ 4.44% ） as well as higher in manufacture O than in manufacture P （ 13.94% vs. 4.39%, X2=6.815, P=0.009）. PFGE showed that 23 strains of L. monocytogenes isolated from the samples of manufacture O had 4 sub- types, and 82.6% shared the same subtype. 4 of the 5 strains isolated from the samples of manufacture P possessed the same sub- type. Conclusions L. monocytogenes isolates are detected in the production process of the 2 frozen drink manufactures, espe- cially detected in the samples collected from the ground and objects contacting with the ground in filling zones. L. monocytogenes i- solates detected in the 2 frozen drink manufactures possess the dominant subtypes. Disinfection and supervision should be strength- ened to prevent the potential risk of frozen drinks contaminated by L. monocytogenes.