The washing stage from a bell pepper commercial packinghouse was assessed to study some of the critical control points related to bacterial cross-contamination. The washing line comprised two overhead spray bars applications: a pre-wash step without peroxyacetic acid (PAA), and a wash step with PAA. The physicochemical characteristics of the wash water and the bacterial quality and safety of the wash water and bell peppers (including aerobic mesophilic bacteria (AMB), Salmonella spp., and Shiga-toxigenic E. coli (STEC)) were studied. Additionally, the performance of commercial test methods (reflectometry, amperometric probe, chronoamperometric sensor) for measuring the residual concentration of PAA was examined. The bacterial load of the pre-wash water (8.7 ± 1.3 log cfu/100 mL AMB) was very high and thus peppers after the pre-wash showed a significantly higher bacterial load (4.9 ± 0.9 log cfu/g AMB) than the unwashed (3.8 ± 0.7 log cfu/g AMB) or the washed peppers (3.3 ± 0.8 log cfu/g AMB) (p < 0.05). However, no pathogenic bacteria were detected in bell pepper samples (n = 40), and only one water sample was confirmed positive for STEC (n = 64, 1.6% prevalence). The chronoamperometric sensor (PAASense) and the online amperometric probe showed similar results, while the reflectometry (Quantofix) significantly sub estimated (p < 0.05) PAA concentration. The results obtained highlight the need for interventions to improve hygiene in the washing line to ensure the microbiological quality and safety of bell peppers. The maintenance of optimal PAA concentrations in all the washing steps is critical for reducing the chance of water-mediated cross-contamination.

中文翻译：

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在商业包装厂中，用过氧乙酸洗涤过的青椒的微生物安全性受到影响的关键点。

评估了甜椒商品包装厂的洗涤阶段，以研究与细菌交叉污染有关的一些关键控制点。清洗线包括两个架空喷杆应用：不使用过氧乙酸（PAA）的预清洗步骤和使用PAA的清洗步骤。研究了洗涤水的理化特性，以及洗涤水和甜椒（包括需氧中温细菌（AMB），沙门氏菌和志贺毒素大肠杆菌（STEC））的细菌质量和安全性。此外，还检查了用于测量PAA残留浓度的商业测试方法（反射法，安培探针，计时电流传感器）的性能。预洗水的细菌载量（8.7±1。3 log cfu / 100 mL AMB）非常高，因此预洗后的辣椒显示的细菌载量（4.9±0.9 log cfu / g AMB）显着高于未洗净的（3.8±0.7 log cfu / g AMB）或胡椒粉（3.3±0.8 log cfu / g AMB）（p <0.05）。但是，在灯笼椒样品中未检出任何致病菌（n = 40），只有一个水样被确认为STEC阳性（n = 64，患病率为1.6％）。计时电流传感器（PAASense）和在线电流探头显示了相似的结果，而反射法（Quantofix）明显低于（p <0.05）PAA浓度。获得的结果突出表明需要采取干预措施来改善清洗生产线的卫生状况，以确保青椒的微生物质量和安全性。