Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824.
Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, Indiana 47907, USA.
J Food Prot. 2022 Aug 1;85(8):1210-1220. doi: 10.4315/JFP-22-076.
Outbreaks of enteric pathogens linked to wheat flour have led the wheat milling industry to seek solutions addressing this food safety concern. Chlorinated water at 400 to 700 ppm has been used in the flour milling industry as a tempering aid to control growth of yeast and mold in tempering bins. However, the effectiveness of chlorinated water for inactivating enteric pathogens on wheat kernels was unknown. Five strains of Shiga toxin-producing Escherichia coli and two strains of Salmonella were inoculated onto hard red spring wheat at 7 log CFU/g and stored at room temperature for 1 month. Inoculated wheat was tempered with four concentrations (0, 400, 800, and 1,200 ppm) of chlorinated water (pH 6.5). The reduction due to chlorine was determined by calculating change in microbial loads at each chlorine level by using the response at 0 ppm as a reference. Uninoculated wheat tempered with chlorinated water was used to measure flour quality parameters. Changes in pathogen population over 18 h ranged from -2.35 to -0.30 log CFU/g with 800 ppm of chlorinated water and were not significantly different from changes at 400 and 1,200 ppm. Significant (P < 0.05) differences in the extent of reduction were observed among strains. However, the effect of chlorinated water at reducing native microbes on wheat kernels was minimal, with an average reduction of 0.39 log CFU/g for all concentrations. No significant (P > 0.05) changes occurred in flour quality and gluten functionality or during bread making for grains tempered at 400 and 800 ppm of chlorinated water. There were small but significant (P < 0.05) changes in flour protein content, final viscosity, and water absorption when tempered with 1,200 ppm of chlorinated water. The data showed that the level of chlorinated water currently used in industry for tempering could reduce enteric pathogen numbers by 1.22 log CFU/g for Shiga toxin-producing Escherichia coli and 2.29 log CFU/g for Salmonella, with no significant effects on flour quality and gluten functionality.
与小麦粉有关的食源性病原体的爆发促使制粉行业寻求解决这一食品安全问题的方法。在制粉行业中，400 至 700ppm 的氯水被用作调质助剂，以控制调质仓中酵母和霉菌的生长。然而，氯水对小麦颗粒中肠病原体的灭活效果尚不清楚。将 5 株产志贺毒素大肠杆菌和 2 株沙门氏菌接种到硬质红春小麦上，接种量为 7logCFU/g，在室温下储存 1 个月。用 4 个浓度（0、400、800 和 1200ppm）的氯水（pH6.5）对接种小麦进行调质。通过计算每个氯水平下微生物负荷的变化，利用 0ppm 时的响应作为参考，确定氯的减少量。用氯水调质的未接种小麦用于测量面粉质量参数。在 18 小时内，病原体种群的变化范围为-2.35 至-0.30logCFU/g，用 800ppm 的氯水，与 400 和 1200ppm 的变化无显著差异。不同菌株之间观察到减少程度的显著差异（P<0.05）。然而，氯水对小麦颗粒中原生微生物的减少作用很小，所有浓度的平均减少量为 0.39logCFU/g。用 400 和 800ppm 的氯水处理的谷物，面粉质量和谷朊粉功能没有显著变化（P>0.05），或在面包制作过程中没有显著变化（P>0.05）。用 1200ppm 的氯水处理时，面粉蛋白含量、最终黏度和吸水率有小但显著的变化（P<0.05）。数据表明，目前工业上用于调质的氯水水平可使产志贺毒素大肠杆菌减少 1.22logCFU/g，沙门氏菌减少 2.29logCFU/g，对面粉质量和谷朊粉功能无显著影响。
