生菜中蜡样芽孢杆菌污染水平风险分析

Analysis of Contamination Level of Bacillus cereus in Fresh Lettuce

研究生菜中蜡样芽孢杆菌的污染状况,并对蜡样芽孢杆菌可能引发的公共卫生风险进行初步评估,为选择合适的风险管理措施提供依据。筛查宝坻基地水培生菜、蓟州基地水培生菜、市售露地大棚生菜中蜡样芽孢杆菌的初始污染量及可能污染来源,结合居民对生菜食用习惯的膳食回顾性调查,采用@Risk 6软件评估最终食用时生菜中蜡样芽孢杆菌的含量。结果表明:蓟州基地水培生菜、宝坻基地水培生菜、市售露地大棚生菜的初始污染量平均水平分别为6.9×10~2、1.5×10~2、1.4×10~2 CFU/g,结合200份居民对生菜食用习惯的调研数据,应用@Risk 6软件经1 000次迭代模拟评估食用时蜡样芽孢杆菌含量超过中毒诊断限值10~5 CFU/g的概率分别为10.7%、12.3%、7.1%,且贮藏温度最终污染量/概率分布的相关性最大。蓟州基地水培生菜的可能污染来源为基质,宝坻基地水培生菜的可能污染来源主要为营养液,其次为基质。基地水培生菜的初始污染量较市售露地大棚生菜明显偏高,这与水培生菜的水床流通式栽培模式相关,建议基地水培生菜采取有效的风险管理措施,严格控制初始污染量及基质和营养液的环境交叉污染。依据现有生菜中蜡样芽孢杆菌初始污染量及居民食用习惯,建议居民购买生菜后,严格控制贮藏温度,可有效保证食用安全。

To study the pollution of Bacillus cereus in fresh lettuce,and preliminary assessment of the possible public health risks caused by Bacillus cereus,so as to provide references for adopting effective risk management measures.Screening the initial contamination and possible source of contamination of the Bacillus cereus in hydroponic lettuce of Baodi base and Jizhou base and outdoor shed lettuce of market.The consumption pattern of the fresh lettuce was investigated in Tianjin residents by retrospective dietary survey.The quantitative risk assessment for Bacillus cereus in fresh lettuce was made by a software of@Risk 6 Ranger.Results showed that the initial pollution levels of hydroponic lettuce of Baodi base and Jizhou base and outdoor shed lettuce of market were 6.9×102,1.5×102,1.4×102 CFU/g respectively.Combining 200 residents'survey data on the eating habits of lettuce.The probability that the content of Bacillus cereus exceeded the diagnostic limit of 105 CFU/g of poisoning was 10.7%,12.3%and 7.1%respectively after 1 000 iterations of@Risk 6 software.Moreover,the ultimate pollution/probability distribution of the storage temperature was the most relevant.The potential source of contamination of the hydroponic lettuce in the Jizhou base was the matrix.The possible source of contamination of the hydroponic lettuce in baodi base was the nutrient solution,followed by the matrix.The initial contamination of the lettuce in the base was significantly higher than that in the market.This is related to the water bed circulation cultivation pattern of the lettuce.It is recommended to take effective risk management measures,strictly control the initial pollution and environmental cross contamination of substrate and nutrient solution.On the basis of existing lettuce waxy bacillus initial pollution,it is recommended that the residents should purchase the lettuce and strictly control the storage temperature,so as to ensure the safety of food.