卤豆干生产过程微生物检测及安全控制

目的：确定卤豆干车间、设备及重要工序菌落总数污染情况，为保证卤豆干品质和安全控制提供理论依据。方法：根据GB4789.2-2010《食品微生物学检验 菌落总数测定》和大气微生物评级标准，对卤豆干车间空气、设备及重要工序进行菌落总数测定并评级。结果：豆腐制作车间空气菌落总数（3.98±0.14）（lg（CFU/m3）），生产设备接触面及操作人员的手菌落总数均高于4.50（lg（CFU/m2））；原料、泡豆、干豆腐和调味菌落总数分别为（6.21±0.49）、（7.28±1.30）、（5.54±0.28）、（7.32±0.30）（lg（CFU/g）），评级为污染至严重污染；熟浆、豆腐脑、卤前清洗和灭菌后的豆腐菌落总数为（2.48±0.07）、（2.47±0.16）、（3.01±0.15）、（2.11±0.30）（lg（CFU/g）），评级为清洁；Duncan’s新复极差法分析结果表明不同生产工序间菌落总数差异显著。结论：车间环境、生产设备及操作人员易对卤豆干造成二次污染；微生物分布与生产工序密切相关；原料、泡豆、烘烤和调味是影响卤豆干食品安全的关键工序；煮浆、豆腐脑、卤前清洗和灭菌是减少微生物污染的关键工序。

Microbial Detection and Safety Control during Production of Stewed Dried Tofu

Objective: To assess microbial contamination of the workshop, equipment and critical procedures during theproduction of stewed dried tofu by aerobic plate count (APC). Methods: APC levels were tested and graded according toGB4789.2-2010 and rating standard of microorganisms in the air. Results: The APC was (3.98 ± 0.14) (lg (CFU/m3))in the air of workshop, higher than 4.50 (lg (CFU/m2)) on the surface of equipment and operators’ hands, (6.21 ±0.49), (7.28 ± 1.30), (5.54 ± 0.28) and (7.32 ± 0.30) (lg (CFU/g)) in soybean, soaked beans, baked tofu and seasonedtofu, respectively, being rated as polluted to seriously polluted, and (2.48 ± 0.07), (2.47 ± 0.16), (3.01 ± 0.15) and(2.11 ± 0.30) (lg (CFU/g)) in cooked pulp, coagulated soymilk, cleaned bean curd before stewing and sterilized bean curd,respectively, all being rated as clean. Duncan’s variance analysis showed that there was a significant difference in APCbetween different production procedures. Conclusions: The poor hygiene conditions in workshop, equipment and operatorsmay lead to secondary pollution. Microbial distribution is closely related to the production process. The starting rawmaterial, soaking, baking and seasoning are the critical procedures for the safety of stewed dried tofu. Pulping, bean curding,cleaning before stewing and sterilization are critical to reduce microbial contamination.