Kealey Erin, Shick Madeline, Kim Minho, Chavez Ruben, Shetley Gordon, Stenger David, Perreau Kirk A, Cooke Allison, Barnett-Neefs Cecil, Stasiewicz Matthew J
Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Ingredion Incorporated, Westchester, IL 60154, USA.
J Food Prot. 2025 Jan 2;88(1):100432. doi: 10.1016/j.jfp.2024.100432. Epub 2024 Dec 14.
Corn wet milling (CWM) and corn starch flash drying processing conditions reduce undesirable microorganisms, such as Salmonella. Finished products are historically safe, with intrinsic properties such as low water activity inhibiting microbial growth. Corn processors could use quantified levels of reduction in this study of Salmonella surrogate Enterococcus faecium (E. faecium) to update their food safety plans. Industry-relevant conditions for CWM processes were recreated at pilot or lab scale for 3 unit operations: (1) steeping treatment in sulfur dioxide (SO) with low (750 ppm SO, 20 h, 43.3 °C), medium (1,500 ppm SO, 30 h, 48.9 °C), and high (2,200 ppm SO, 40 h, 53.3 °C) treatment conditions; (2) hydrogen peroxide (HO) treatment tested on bench scale with a factorial design (pH 3.5, 4.0, and 4.5), HO concentrations (0.05%, 0.10%, 0.15% (w/w)), and temperatures (32, 38, and 46 °C) for 3 and 6 h; (3) flash drying treatment at 4 different temperatures (149, 177, 204, and 232 °C) with 2 different inoculation methods. E. faecium was reduced during each of these unit operations. By the end of each steeping treatment, E. faecium was consistently below the limit of quantitation (LOQ), meaning >6.5 log CFU/mL reduction in steep water, and >3.7 log CFU/g reduction in ground corn. The peroxide step had a reduction range from 0.03 log CFU/mL in the control group (0% HO added) to >6 log CFU/mL observed in the high-intensity treatment of corn starch slurry. Flash drying had a reduction range from 1.7 to 2.7 log CFU/g. There was also no biologically meaningful change (<1 log CFU/g reduction) of E. faecium counts during an 8-week survival study of the dried final product. This hurdle approach study shows that existing CWM conditions are effective for Salmonella surrogate reduction through processing into finished starch and provides quantified E. faecium reductions for use in food safety plans.
玉米湿法研磨（CWM）和玉米淀粉闪蒸干燥工艺条件可减少沙门氏菌等有害微生物。从历史上看，成品是安全的，其内在特性如低水分活度可抑制微生物生长。玉米加工商可利用本研究中沙门氏菌替代菌屎肠球菌（屎肠球菌）的量化减少水平来更新其食品安全计划。在中试或实验室规模下，针对3个单元操作重现了与行业相关的CWM工艺条件：（1）在二氧化硫（SO）中进行浸泡处理，处理条件为低（750 ppm SO，20小时，43.3°C）、中（1500 ppm SO，30小时，48.9°C）和高（2200 ppm SO，40小时，53.3°C）；（2）在实验室规模上，采用析因设计对过氧化氢（HO）处理进行测试，测试因素包括pH值（3.5、4.0和4.5）、HO浓度（0.05%、0.10%、0.15%（w/w））和温度（32、38和46°C），处理时间为3小时和6小时；（3）在4个不同温度（149、177、204和232°C）下，采用2种不同接种方法进行闪蒸干燥处理。在这些单元操作中的每一个过程中，屎肠球菌数量都有所减少。在每次浸泡处理结束时，屎肠球菌数量始终低于定量限（LOQ），这意味着浸泡水中的减少量>6.5 log CFU/mL，磨碎玉米中的减少量>3.7 log CFU/g。过氧化物处理步骤的减少范围从对照组（添加0% HO）中的0.03 log CFU/mL到玉米淀粉浆料高强度处理中观察到的>6 log CFU/mL。闪蒸干燥的减少范围为1.7至2.7 log CFU/g。在干燥最终产品的8周存活研究中，屎肠球菌数量也没有生物学上有意义的变化（减少量<1 log CFU/g）。这项障碍方法研究表明，现有的CWM条件对于通过加工成成品淀粉减少沙门氏菌替代菌是有效的，并提供了用于食品安全计划的屎肠球菌量化减少量。
