Significance of Tempering Parameters on the E. coli Load of Wheat Grains and Mill Fractions During Milling

Background and Objectives Wheat tempering is a crucial step in wheat milling. This manuscript investigated the significance of tempering parameters on the Escherichia coli contamination level of wheat grains and milling fractions during milling. Findings Higher tempering moisture and time reduced (0.12−0.31 log CFU/g; p < 0.05) the E. coli load of wheat grains. Inoculation level, temperature, and time influenced the extent of E. coli load reduction on wheat grains after tempering (0.59−2.86 log CFU/g; p < 0.0001). These parameters also influenced the E. coli reduction in non‐flour (1.8−3.23 log CFU/g; p < 0.05) and flour (2.17−4.56 log CFU/g; p < 0.05) fractions produced. Inoculation level (19.25%−60.19%) and temperature (5.14%−35.31%) were the main contributors to the total variance of the E. coli load reductions measured in wheat grains and milling fractions. Conclusions Tempering parameters influence the redistribution of E. coli contamination in wheat grains and milling fractions. The presence of high inoculation load along with the use of higher temperature, and longer tempering time increased the load reductions observed. Significance and Novelty This study shows that tempering conditions can be manipulated to mitigate potential E. coli contamination in wheat milling operations.