Nan Yuchen, Rodas-Gonzalez Argenis, Stanford Kim, Nadon Celine, Yang Xianqin, McAllister Tim, Narváez-Bravo Claudia
Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada.
Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada.
Front Microbiol. 2022 May 30;13:863778. doi: 10.3389/fmicb.2022.863778. eCollection 2022.
Interactions of Shiga toxin-producing (STEC; O103:H2) with lactic acid bacteria (LAB) or spoilage bacteria (SP) multispecies biofilms on polyurethane (TPU) and stainless-steel (SS) were assessed at 10 and 25°C under wet and dry conditions after 6, 30, and 60 days of storage. One LAB T1: + , and two SP T2: + T3: + were assessed for their ability to form multispecies biofilms with O103:H2. O103:H2 single-species biofilms served as a control positive (T4). Coupons were stored dry (20-50% relative humidity; RH) or moist (60-90% RH) for up to 60 days, at which point O103:H2 transfer to beef and survival was evaluated. At 25°C, T3 decreased beef contamination with O103:H2 by 2.54 log CFU/g ( < 0.001). Overall, at 25°C contamination of beef with O103:H2 decreased ( < 0.001) from 3.17 log CFU/g on Day 6 to 0.62 log CFU/g on Day 60. With 60 days dry biofilms on TPU, an antagonistic interaction was observed among O103:H2 and multispecies biofilm T1 and T3. O103:H2 was not recovered from T1 and T3 after 60 days but it was recovered (33%) from T2 and T4 dry biofilms. At 10°C, contamination of beef with O103:H2 decreased ( < 0.001) from 1.38 log CFU/g after 6 days to 0.47 log CFU/g after 60 days. At 10°C, recovery of O103:H2 from 60 days dry biofilms could only be detected after enrichment and was always higher for T2 than T4 biofilms. Regardless of temperature, the transfer of O103:H2 to beef from the biofilm on TPU was greater ( < 0.001) than SS. Moist biofilms also resulted in greater ( < 0.001) cell transfer to beef than dry biofilms at 10 and 25°C. Development of SP or LAB multispecies biofilms with O103:H2 can either increase or diminish the likelihood of beef contamination. Environmental conditions such as humidity, contact surface type, as well as biofilm aging all can influence the risk of beef being contaminated by STEC within multi-species biofilms attached to food contact surfaces.
在10℃和25℃的干湿条件下，储存6天、30天和60天后，评估产志贺毒素大肠杆菌（STEC；O103:H2）与聚氨酯（TPU）和不锈钢（SS）上的乳酸菌（LAB）或腐败菌（SP）多物种生物膜之间的相互作用。评估了一种LAB T1: + ，以及两种SP T2: + 和T3: + 与O103:H2形成多物种生物膜的能力。O103:H2单物种生物膜作为对照阳性（T4）。试片在干燥（相对湿度20 - 50%；RH）或潮湿（相对湿度60 - 90%）条件下储存长达60天，此时评估O103:H2向牛肉的转移和存活情况。在25℃时，T3使牛肉中O103:H2的污染减少了2.54 log CFU/g（P < 0.001）。总体而言，在25℃时，牛肉中O103:H2的污染从第6天的3.17 log CFU/g降至第60天的0.62 log CFU/g（P < 0.001）。对于TPU上60天的干燥生物膜，观察到O103:H2与多物种生物膜T1和T3之间存在拮抗相互作用。60天后，T1和T3中未检测到O103:H2，但在T2和T4干燥生物膜中检测到了O103:H2（33%）。在10℃时，牛肉中O103:H2的污染从6天后的1.38 log CFU/g降至60天后的0.47 log CFU/g（P < 0.001）。在10℃时，仅在富集后才能检测到60天干燥生物膜中O103:H2的回收，且T2生物膜中的回收量始终高于T4生物膜。无论温度如何，TPU上生物膜中O103:H2向牛肉的转移量均大于SS上的转移量（P < 0.001）。在10℃和25℃时，潮湿生物膜导致的细胞向牛肉的转移量也大于干燥生物膜（P < 0.001）。SP或LAB与O103:H2形成的多物种生物膜的发展可能会增加或降低牛肉污染的可能性。湿度、接触表面类型以及生物膜老化等环境条件都会影响附着在食品接触表面的多物种生物膜中牛肉被STEC污染的风险。
