Rutgers, the State University of New Jersey, is best known for its innovative research in medical, environmental and food science. Dr. Donald W. Schaffner is Extension Specialist in Food Science and Distinguished Professor at Rutgers University. His research interests include quantitative microbial risk assessment, predictive food microbiology, handwashing and cross-contamination.
Dr. Schaffner’s participation and leadership in expert handwashing committees led to many of the foundational principles at the core of solutions offered by the Handwashing For Life® Institute.
Don was elected a Fellow of IFT in 2010, of the American Academy for Microbiology in 2014 and of the International Association for Food Protection in 2017. He is active in IAFP, IFT, the Society for Risk Analysis (SRA), the American Society for Microbiology (ASM), and the Conference for Food Protection (CFP).
Dr. Don Schaffner is the co-host of a podcast on microbial food safety at http://foodsafetytalk.com.
Dr. Schaffner on setting safe level standards »
Source: Journal of Food Protection: Vol. 64, No. 1, pp. 72-80.
Quantification and Variability Analysis of Bacterial Cross-Contamination Rates in Common Food Service Tasks
YUHUAN CHEN, KRISTIN M. JACKSON, FABIOLA P. CHEA, and DONALD W. SCHAFFNER
Food Risk Analysis Initiative, Rutgers, the State University of New Jersey, New Brunswick, New Jersey 08901-8520, USA
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 post washed 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 foodservice kitchens.
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