Cross-contamination in the kitchen: estimation of transfer rates for cutting boards, hands and knives.
OBJECTIVE
To quantify cross-contamination in the home from chicken to ready-to-eat salad.


RESULTS
Based on laboratory scenarios performed by de Jong et al. (2008), transfer rates were estimated for Campylobacter jejuni and Lactobacillus casei as a tracer organism. This study showed that transfer characteristics for both micro-organisms were comparable when washing regimes and transfer via items (cutting board, hands and knives) were compared. Furthermore, the study showed that the use of separate transfer rates for transfer from chicken to items and from items to salad will lead to an overestimation of campylobacteriosis risk. Applying good hygienic practices resulted in final levels of bacteria in the salad below the detection limit. Our study showed that it is important to include these data points in model fitting.


CONCLUSIONS
Results obtained in observational studies with Lact. casei can be translated to Camp. jejuni using the transfer rates obtained in this study. Cross-contamination by hands, cutting boards and knives was equally important.


CONCLUSIONS
Cross-contamination should be incorporated in microbiological risk assessments. The present study contributes to this by quantifying transfer of Camp. jejuni and Lact. casei from raw chicken via various contact surfaces into the ready-to-eat product.
van Asselt
E D
ED
Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands. esther.vanasselt@wur.nl
de Jong
A E I
AE
de Jonge
R
R
Nauta
M J
MJ
D000818:Animals; D016123:Campylobacter jejuni / Q000302:isolation & purification*; D002645:Chickens; D015169:Colony Count, Microbial; D003297:Cooking and Eating Utensils; D004866:Equipment Contamination; D005506:Food Contamination / Q000032:analysis* / Q000517:prevention & control; D005511:Food Handling / Q000379:methods; D008962:Models, Theoretical; D014675:Vegetables / Q000382:microbiology*