Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695-7624, USA.
Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695-7624, USA.
J Food Prot. 2023 Jan;86(1):100029. doi: 10.1016/j.jfp.2022.100029. Epub 2022 Dec 15.
Plasma-activated water (PAW) is considered a novel sanitizer for the food industry due to the antimicrobial mechanisms exhibited by reactive oxygen and nitrogen species. The plasma operation parameters can affect the chemistry of PAW and can therefore influence its microbial inactivation efficacy. This study statistically optimized the operating conditions of PAW (activation time, distance from nozzle, and volume of water) using response surface methodology. Two optimized conditions of PAW were identified for the inactivation of planktonic cells of the avirulent strain of Salmonella Typhimurium MHM112 providing a minimum reduction of 6.3 log. All three operating parameters significantly affected the physicochemical characteristics (pH, ORP, EC, nitrite, and nitrate) and microbial inactivation efficacy of PAW. Mixing of small batches using the two optimized conditions to obtain larger volumes did not significantly change the microbial inactivation. However, there were significant reductions in nitrite and nitrate concentrations in PAW due to the mixing of batches while the pH and ORP values remained unaffected. The storage of large volumes of PAW for 25 min at 40-46°C, which is the commercial egg washing temperature in the United States, did not significantly impact S. Typhimurium MHM112 inactivation or the physicochemical characteristics of PAW. A validation study using a cocktail of six pathogenic strains of Salmonella revealed no significant differences in inactivation between the avirulent S. Typhimurium MHM112 and the pathogenic strains, suggesting that the avirulent S. Typhimurium MHM112 may serve as a surrogate for sanitation of S. enterica at the optimized conditions of PAW. The results obtained from this study are useful for our long-term goal of evaluating PAW efficacy in surface egg washing to inactivate Salmonella.
等离子体激活水（PAW）由于活性氧和氮物种表现出的抗菌机制，被认为是食品工业的一种新型消毒剂。等离子体操作参数会影响 PAW 的化学性质，从而影响其微生物失活动力。本研究使用响应面法对 PAW 的操作条件（激活时间、喷嘴距离和水体积）进行了统计学优化。确定了两种优化条件的 PAW 用于失活动力学为 6.3 对数减少的无毒鼠伤寒沙门氏菌 MHM112 浮游细胞。所有三个操作参数都显著影响 PAW 的理化特性（pH 值、氧化还原电位、电导率、亚硝酸盐和硝酸盐）和微生物失活动力。使用两种优化条件混合小批量以获得更大体积不会显著改变微生物失活动力。然而，由于批量混合，PAW 中的亚硝酸盐和硝酸盐浓度显著降低，而 pH 值和氧化还原电位值保持不变。将大量 PAW 在 40-46°C 下储存 25 分钟，这是美国商业鸡蛋清洗温度，不会显著影响鼠伤寒沙门氏菌 MHM112 的失活动力或 PAW 的理化特性。使用六种致病性沙门氏菌的鸡尾酒进行验证研究表明，无毒鼠伤寒沙门氏菌 MHM112 与致病性菌株之间的失活动力没有显著差异，这表明无毒鼠伤寒沙门氏菌 MHM112 可能在 PAW 的优化条件下替代沙门氏菌进行环境卫生。本研究结果对于我们长期评估 PAW 在表面鸡蛋清洗中杀灭沙门氏菌的功效非常有用。
