Animal and Food Science Department, Texas Tech University, Lubbock, TX, USA; Department of Food Science, The University of Tennessee, Knoxville, TN, USA.
Animal and Food Science Department, Texas Tech University, Lubbock, TX, USA; International Center for Food Industry Excellence, Texas Tech University, Lubbock, TX, USA.
Int J Food Microbiol. 2022 Jul 2;372:109697. doi: 10.1016/j.ijfoodmicro.2022.109697. Epub 2022 May 1.
Unpasteurized apple ciders and fresh produce have been linked to multistate outbreaks due to contamination by foodborne pathogens. Organic acids such as benzoic acid are effective antimicrobials, and acidified sodium benzoate (NaB) has been reported to be effective in reducing pathogens inoculated on cherry tomatoes and preventing cross-contamination. Sodium bisulfate (SBS) is a powerful acidulant but has not been studied in combination with NaB. The objective of the present study was to characterize the antibacterial activity of SBS and its combination with NaB in tryptic soy broth (TSB) and apple juice, as well as washing cherry tomatoes. The minimum inhibitory concentration and minimum bactericidal concentration of SBS were all 0.5% w/v (corresponding to TSB medium pH of 4.30) and 1.0% w/v (corresponding to TSB medium pH of 2.88), respectively, for Escherichia coli O157:H7 ATCC 43895, Salmonella Enteritidis ATCC 13076, and Listeria monocytogenes Scott A. In TSB, the triple combination of 1.0% w/v SBS, 0.1% w/v NaB, and 0.02% w/v oregano oil (OO) showed the faster inactivation rate of the three bacteria than treatments with one or two antimicrobials; the activity of double combinations followed the order of 0.1% w/v NaB +1.0% w/v SBS > 0.1% w/v NaB +0.5% w/v SBS + 0.02% w/v OO > 0.1% w/v NaB +0.5% w/v SBS. pH was a critical factor in the activity of antimicrobial combinations in TSB, and L. monocytogenes was more resistant than Gram-negative E. coli O157:H7 and S. Enteritis. In apple juice added with 0.05% w/v NaB, 0.25% w/v SBS, and 0.01% w/v OO alone or in combinations, 5 log CFU/mL or greater reductions in 72 h were observed for E. coli O157:H7 and S. Enteritidis in double and triple combinations, while only the triple combination and the SBS-OO combination resulted in the same effect for L. monocytogenes. For cherry tomatoes inoculated with 6.8 log CFU/g E. coli O157:H7, complete decontamination (>6 log CFU/g) was achieved after soaking for 1 min in solutions containing 0.5-1.5% w/v SBS and 0.1% w/v NaB or 1.5% w/v SBS alone, and no pathogens were detected in all wash solutions containing 0.5-1.5% w/v SBS with and without NaB. The lower pH of wash solutions with a higher amount of SBS was a dominant factor in decontamination and prevention of cross-contamination. The present study showed the potential of SBS and its combination with NaB to enhance the safety of apple juice and cherry tomatoes.
未经巴氏消毒的苹果酒和新鲜农产品由于受到食源性病原体的污染，与多州疫情有关。苯甲酸等有机酸是有效的抗菌剂，据报道酸化的苯甲酸钠（NaB）可有效减少接种在樱桃番茄上的病原体，并防止交叉污染。硫酸氢钠（SBS）是一种强力酸化剂，但尚未与 NaB 一起进行研究。本研究旨在研究 SBS 及其与 NaB 在胰蛋白酶大豆肉汤（TSB）和苹果汁中的组合，以及对樱桃番茄进行清洗时的抗菌活性。SBS 的最小抑菌浓度和最小杀菌浓度均为 0.5% w/v（相当于 TSB 培养基 pH 值 4.30）和 1.0% w/v（相当于 TSB 培养基 pH 值 2.88），用于大肠杆菌 O157:H7 ATCC 43895、肠炎沙门氏菌 ATCC 13076 和单核细胞增生李斯特菌 Scott A。在 TSB 中，1.0% w/v SBS、0.1% w/v NaB 和 0.02% w/v牛至油（OO）的三重组合对三种细菌的灭活速度比一种或两种抗菌剂的处理更快；双组合的活性顺序为 0.1% w/v NaB +1.0% w/v SBS>0.1% w/v NaB +0.5% w/v SBS+0.02% w/v OO>0.1% w/v NaB +0.5% w/v SBS。pH 是 TSB 中抗菌组合活性的关键因素，与革兰氏阴性大肠杆菌 O157:H7 和肠炎沙门氏菌相比，单核细胞增生李斯特菌更具抗性。在添加了 0.05% w/v NaB、0.25% w/v SBS 和 0.01% w/v OO 的苹果汁中，单独或组合使用时，在 72 小时内，E. coli O157:H7 和肠炎沙门氏菌的减少量达到 5 个对数 CFU/mL 或更多，而只有三重组合和 SBS-OO 组合对单核细胞增生李斯特菌产生相同的效果。对于接种了 6.8 log CFU/g 大肠杆菌 O157:H7 的樱桃番茄，用含有 0.5-1.5% w/v SBS 和 0.1% w/v NaB 或单独 1.5% w/v SBS 的溶液浸泡 1 分钟后可完全去污（>6 log CFU/g），并且所有含有 0.5-1.5% w/v SBS 的洗涤溶液中均未检测到病原体。含有较高 SBS 量的洗涤溶液的较低 pH 值是去污和防止交叉污染的主要因素。本研究表明 SBS 及其与 NaB 的组合具有提高苹果汁和樱桃番茄安全性的潜力。
