Michigan State University, Department of Biosystems and Agricultural Engineering, East Lansing, MI, 48824, USA; Current Address: University of Costa Rica, Department of Biosystems Engineering, Engineering Building, Rodrigo Facio Brenes Campus, San Pedro, San José, Costa Rica.
Michigan State University, Department of Biosystems and Agricultural Engineering, East Lansing, MI, 48824, USA.
Food Microbiol. 2020 Dec;92:103607. doi: 10.1016/j.fm.2020.103607. Epub 2020 Jul 29.
Bacterial cross-contamination between foods and contact surfaces can increase food safety risk; however, these processes are not well described in terms of fundamental variables. The objective was to determine the effect of sliding speed (3.75, 5.00, or 7.75 mm/s), contact time (5 or 40 s), normal pressure (1217 to 8869 Pa), and number of sequential contacts on bacterial transfer to/from potato samples and stainless steel surfaces. Potato samples (11 g, 3 × 3 × 1 cm) were either pulled across a stainless steel plate inoculated with Salmonella Typhimurium LT2 (~6.23 Log CFU/cm) (dynamic contact) or placed on the inoculated plate for multiple sequential contacts on uninoculated squares (static contact). Salmonella on the potato and steel plate then were quantified by plating on modified trypticase soy agar. Bacterial transfer increased with increasing sliding speed (P = 0.0098) in dynamic tests and with contact time (P < 0.0001) in static tests. Salmonella on the inoculated potatoes decreased (P < 0.0001) from ~6.5 to ~5.5 Log CFU after 18 sequential static contacts with stainless steel. Reporting transfer results based on fundamental variables will improve the overall impact of bacterial transfer research on equipment design, cleaning/sanitation strategies, and overall food safety.
细菌在食品和接触表面之间的交叉污染会增加食品安全风险；然而，这些过程在基本变量方面还没有得到很好的描述。本研究的目的是确定滑动速度（3.75、5.00 或 7.75 mm/s）、接触时间（5 或 40 s）、法向压力（1217 至 8869 Pa）和连续接触次数对细菌从马铃薯样品和不锈钢表面转移到/转移到马铃薯样品和不锈钢表面的影响。马铃薯样品（11 g，3×3×1 cm）要么在接种了鼠伤寒沙门氏菌 LT2（6.23 Log CFU/cm）的不锈钢板上被拉动（动态接触），要么放在接种板上进行多个未接种正方形的连续接触（静态接触）。然后通过在改良胰蛋白酶大豆琼脂上划线来定量马铃薯和钢板上的沙门氏菌。在动态试验中，细菌转移随滑动速度的增加而增加（P = 0.0098），在静态试验中随接触时间的增加而增加（P < 0.0001）。在与不锈钢进行 18 次连续静态接触后，接种马铃薯上的沙门氏菌数量从6.5 Log CFU 减少到~5.5 Log CFU（P < 0.0001）。基于基本变量报告转移结果将提高细菌转移研究对设备设计、清洁/卫生策略和整体食品安全的整体影响。
