Stopforth Jarret D, Samelis John, Sofos John N, Kendall Patricia A, Smith Gary C
Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523-1171, USA.
J Food Prot. 2003 Dec;66(12):2258-66. doi: 10.4315/0362-028x-66.12.2258.
This study evaluated resistance to sanitizing solutions of Escherichia coli O157:H7 cells forming biofilms on stainless steel coupons exposed to inoculated meat decontamination runoff fluids (washings). A previously acid-adapted culture of a rifampicin-resistant derivative of E. coli O157:H7 strain ATCC 43895 was inoculated in unsterilized or sterilized combined hot-water (85 degrees C) and cold-water (10 degrees C) (50/50 [vol/vol]) composite water (W) washings (pH 6.29 to 6.47) and in W washings mixed with 2% acetic acid (pH 4.60 to 4.71) or in 2% lactic acid W washings (pH 4.33 to 4.48) at a ratio of 1/99 (vol/vol). Stainless steel coupons (2 by 5 by 0.08 cm) were submerged in the inoculated washings and stored for up to 14 days at 15 degrees C. Survival of E. coli O157:H7 was determined after exposure (0 to 60 s for cells in suspension and 0 to 300 s for attached cells) to two commercial sanitizers (150 ppm peroxyacetic acid and 200 ppm quaternary ammonium compound) at 2, 7, and 14 days. E. coli O157:H7 attached more rapidly to coupons submerged in washings containing the natural flora than to those without. The attached cells were more resistant to the effects of the sanitizers than were the cells in suspension, and survival was highest in the presence of the natural flora. Attached cells in the presence of dilute acid washings were more sensitive to subsequent sanitizer treatments than were cells generated in the presence of W washings. Under the conditions of this study, cells of E. coli O157:H7 in W washings were more sensitive to acidic (peroxyacetic acid) than to alkaline (quaternary ammonium) sanitizers during storage. These results suggest that meat processing plants that apply no decontamination or that use only water washings of meat should consider using acidic sanitizers to enhance biofilm removal. Plants that apply both water and acidic washings may create a sublethal acid-stressing environment in the runoff fluids, sensitizing biofilm cells to subsequent sanitizing treatments.
本研究评估了在接种肉品去污冲洗液（洗涤水）的不锈钢试片上形成生物膜的大肠杆菌O157:H7细胞对消毒溶液的抗性。将一株先前经酸适应的大肠杆菌O157:H7菌株ATCC 43895的耐利福平衍生物培养物接种于未灭菌或灭菌的热水（85℃）和冷水（10℃）（50/50[体积/体积]）复合水（W）洗涤水（pH 6.29至6.47）中，以及接种于与2%乙酸混合的W洗涤水（pH 4.60至4.71）或2%乳酸W洗涤水（pH 4.33至4.48）中，比例为1/99（体积/体积）。将不锈钢试片（2×5×0.08厘米）浸入接种的洗涤水中，并在15℃下储存长达14天。在2天、7天和14天后，将大肠杆菌O157:H应对两种商用消毒剂（150 ppm过氧乙酸和200 ppm季铵化合物）暴露（悬浮细胞暴露0至60秒，附着细胞暴露0至300秒）后，测定其存活率。与浸入不含天然菌群的洗涤水中的试片相比，大肠杆菌O157:H7附着在浸入含天然菌群洗涤水中的试片上的速度更快。附着细胞比悬浮细胞对消毒剂的作用更具抗性，并且在存在天然菌群的情况下存活率最高。与在W洗涤水存在下产生的细胞相比，在稀酸洗水存在下的附着细胞对随后的消毒剂处理更敏感。在本研究条件下，在储存期间，W洗涤水中的大肠杆菌O157:H7细胞对酸性（过氧乙酸）消毒剂比对碱性（季铵）消毒剂更敏感。这些结果表明，不进行去污处理或仅使用肉品水洗的肉类加工厂应考虑使用酸性消毒剂以增强生物膜的去除。同时使用水和酸洗的工厂可能会在冲洗液中创造一个亚致死性的酸应激环境，使生物膜细胞对随后的消毒处理敏感。
Zotero 插件