Quantification and variability analysis of bacterial cross-contamination rates in common food service tasks.
This study investigated bacterial transfer rates between hands and other common surfaces involved in food preparation in the kitchen. Nalidixic acid-resistant Enterobacter aerogenes B199A was used as a surrogate microorganism to follow the cross-contamination events. Samples from at least 30 different participants were collected to determine the statistical distribution of each cross-contamination rate and to quantify the natural variability associated with that rate. The transfer rates among hands, foods, and kitchen surfaces were highly variable, being as low as 0.0005% and as high as 100%. A normal distribution was used to describe the variability in the logarithm of the transfer rates. The mean +/- SD of the normal distributions were, in log percent transfer rate, chicken to hand (0.94 +/- 0.68), cutting board to lettuce (0.90 +/- 0.59), spigot to hand (0.36 +/- 0.90), hand to lettuce (-0.12 +/- 1.07), prewashed hand to postwashed hand (i.e., hand washing efficiency) (-0.20 +/- 1.42), and hand to spigot (-0.80 +/- 1.09). Quantifying the cross-contamination risk associated with various steps in the food preparation process can provide a scientific basis for risk management efforts in both home and food service kitchens.
Chen
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Y
Food Risk Analysis Initiative, Rutgers-the State University of New Jersey, New Brunswick 08901-8520, USA.
Jackson
K M
KM
Chea
F P
FP
Schaffner
D W
DW
D000818:Animals; D002645:Chickens; D015169:Colony Count, Microbial; D021902:Enterobacter aerogenes; D005069:Evaluation Studies as Topic; D005260:Female; D005506:Food Contamination / Q000517:prevention & control; D005511:Food Handling; D005516:Food Microbiology; D006225:Hand / Q000382:microbiology; D006801:Humans; D007700:Kinetics; D018545:Lactuca / Q000382:microbiology; D008297:Male; D008460:Meat / Q000382:microbiology; D012308:Risk Management; D016008:Statistical Distributions