Face Masks as Sources of Cross-Contamination during Food Preparation

Amid the COVID-19 pandemic, mask-wearing has become a common practice in the foodservice industry to prevent the spread of respiratory diseases. Like kitchen utensils, a mask may serve as a vehicle for cross-contamination of pathogens during food handling. The objective of this study was to quantify cross-contamination between tasks of handling contaminated chicken and chopping lettuce. Chicken breasts were inoculated with a high or a low level of nonpathogenic Escherichia coli surrogates (ca. 6 or 4 log CFU/ml) and sliced for 1, 5, or 10 min. During slicing, duplicate, single-use medical masks were touched each minute. One mask was immediately sampled, but the second mask was used to contaminate lettuce by touching the mask each minute while chopping the lettuce for 5 min. E. coli were enumerated from the second mask and lettuce. Masks touched while slicing both high- and low-inoculated chicken showed significant contamination (0.8–4.9 log CFU/cm2) after each slicing scenario of 1, 5, or 10 min (P > 0.05). Lettuce was significantly contaminated regardless of inoculation level (1.0–3.2 log CFU/g). Slicing time was a significant factor in some cases (P < 0.05), whereas inoculation level was not (P > 0.05). Data indicate masks can be a source of cross-contamination if not replaced appropriately.