McCaughan Kyle J, Scott Zoe, Rock Channah, Kniel Kalmia E
Department of Animal and Food Sciences, University of Delaware, Newark, Delaware, USA.
Department of Environmental Science, University of Arizona, Maricopa, Arizona, USA.
Appl Environ Microbiol. 2025 Jan 31;91(1):e0165324. doi: 10.1128/aem.01653-24. Epub 2024 Dec 6.
Agricultural water is a potential source of microbial contamination whereby and can enter the food supply. To reduce this risk, effective sanitization of agricultural water may be critical to food safety. As such, it is important to investigate the effects of aqueous peracetic acid (PAA) and chlorine (Cl) on bacteria and protozoa at different treatment times and temperatures in agricultural water with respect to key water characteristics. Multiple concentrations of each sanitizer, ranging from 3 to 200 ppm, were prepared in recently collected agricultural water, the solution was brought to the desired temperature, and the target organisms were added and left for the desired contact time (5 or 10 minutes) when sodium metabisulfite was added to neutralize the sanitizers. Bacterial samples were enumerated on MacConkey or XLT4 agar. Samples with protozoa were added to mammalian cell culture (HCT-8 cells for and MDBK cells for ). After 48 hours, the infected cells were collected, DNA extracted and infectivity assessed by quantitative PCR (qPCR). Low and high concentrations of sanitizer were effective at eliminating bacteria with Cl being significantly ( < 0.05) more effective. The greatest reductions in and (3.48 log and 2.5 log cfu/mL, respectively) were observed after 10 minutes of exposure to 10 ppm Cl. Concentrations of sanitizer 50 ppm and lower resulted in insignificant ( > 0.05) reductions in parasite infectivity of less than 1 log for both organisms. A 200 ppm PAA treatment reduced infectious oocyst populations by 3.8 log for and 2.6 log for , with Cl being significantly ( < 0.05) less effective against these organisms.
This research is critical to inform decisions regarding the application and use of sanitizers in pre-harvest agricultural water settings to enhance food safety. Understanding the effectiveness of chlorine (Cl) and peracetic acid (PAA) on bacteria and protozoa will allow for the more efficient and practical use of these sanitizers, thus improving agricultural practices in ways that are beneficial to both growers and consumers.
农业用水是微生物污染的一个潜在来源，病原体可借此进入食品供应链。为降低这种风险，对农业用水进行有效的消毒处理对于食品安全可能至关重要。因此，针对农业用水的关键水质特性，研究过氧乙酸（PAA）和氯（Cl）在不同处理时间和温度下对细菌和原生动物的影响具有重要意义。在最近采集的农业用水中制备了每种消毒剂的多种浓度，范围从3至200 ppm，将溶液加热到所需温度，加入目标生物体，并在加入焦亚硫酸钠以中和消毒剂后，使其接触所需的时间（5或10分钟）。细菌样本在麦康凯或XLT4琼脂上计数。含有原生动物的样本加入哺乳动物细胞培养物中（针对隐孢子虫使用HCT - 8细胞，针对贾第虫使用MDBK细胞）。48小时后，收集受感染的细胞，提取DNA并通过定量PCR（qPCR）评估感染性。低浓度和高浓度的消毒剂对消除细菌均有效，其中Cl的效果显著更好（P < 0.05）。在接触10 ppm Cl 10分钟后，观察到隐孢子虫和贾第虫的最大减少量分别为3.48 log和2.5 log cfu/mL。对于两种生物体，50 ppm及更低浓度的消毒剂导致寄生虫感染性的降低不显著（P > 0.05），降低量小于1 log。200 ppm的PAA处理使隐孢子虫的感染性卵囊数量减少3.8 log，使贾第虫减少2.6 log，Cl对这些生物体的效果显著较差（P < 0.05）。
本研究对于为收获前农业用水环境中消毒剂的应用和使用提供决策依据以提高食品安全至关重要。了解氯（Cl）和过氧乙酸（PAA）对细菌和原生动物的有效性将有助于更高效、实际地使用这些消毒剂，从而以有利于种植者和消费者的方式改进农业实践。
