PDF(Pubmed)
Abstract：
The increase in vegetable consumption has underlined the importance of minimizing the risks associated with microbiological contamination of fresh produce. The critical stage of the vegetable washing process has proven to be a key point for cross-contamination and the persistence of pathogens. In this context, the agri-food industry has widely adopted the use of disinfectants to reduce the bacterial load in the wash water. Therefore, we conducted laboratory-scale experiments in order to demonstrate the antimicrobial activity of disinfectants used in the wash tank of agro-food industries. Different wash water matrices of shredded lettuce, shredded cabbage, diced onion, and baby spinach were treated with sodium hypochlorite (NaClO), chlorine dioxide (ClO2), and per-oxyacetic acid (PAA) at recommended concentrations. To simulate the presence of pathogenic bacteria, a cocktail of E. coli O157:H7 was inoculated into the process water samples (PWW) to determine whether concentrations of disinfectants inhibit the pathogen or bring it to a viable non-culturable state (VBNC). Hereby, we used quantitative qPCR combined with different photo-reactive dyes such as ethidium monoazide (EMA) and propidium monoazide (PMA). The results indicated that concentrations superior to 20 ppm NaClO inhibit the pathogen E. coli O157:H7 artificially inoculated in the process water. Concentrations between 10-20 ppm ClO2 fail to induce the pathogen to the VBNC state. At concentrations of 80 ppm PAA, levels of culturable bacteria and VBNC of E. coli O157:H7 were detected in all PWWs regardless of the matrix. Subsequently, this indicates that the recommended concentrations of ClO2 and PAA for use in the fresh produce industry wash tank do not inhibit the levels of E. coli O157:H7 present in the wash water.
摘要：
蔬菜消费量的增加强调了将与新鲜农产品的微生物污染相关的风险降至最低的重要性。事实证明，蔬菜洗涤过程的关键阶段是交叉污染和病原体持续存在的关键点。在这种情况下，农业食品工业广泛采用消毒剂来减少洗涤水中的细菌负荷。因此,我们进行了实验室规模的实验，以证明用于农用食品工业洗涤槽的消毒剂的抗菌活性。不同的洗涤水基质切碎的生菜，卷心菜丝,洋葱丁,和婴儿菠菜用次氯酸钠（NaClO）处理，二氧化氯(ClO2),和推荐浓度的氧乙酸（PAA）。为了模拟病原菌的存在，将大肠杆菌O157:H7的混合物接种到工艺用水样品(PWW)中,以确定消毒剂的浓度是否抑制病原体或使其达到可行的不可培养状态(VBNC)。特此,我们使用定量qPCR结合不同的光活性染料，如单叠氮化物乙锭（EMA）和单叠氮化物丙锭（PMA）。结果表明,高于20ppmNaClO的浓度抑制人工接种在工艺水中的病原体大肠杆菌O157:H7。10-20ppmClO2之间的浓度不能将病原体诱导为VBNC状态。当PAA浓度为80ppm时，无论基质如何，在所有PWW中都检测到大肠杆菌O157:H7的可培养细菌和VBNC水平。随后，这表明用于新鲜农产品工业洗涤槽的ClO2和PAA的推荐浓度不会抑制洗涤水中存在的大肠杆菌O157:H7的水平。
