Cross-contamination in the kitchen: estimation of transfer rates for cutting boards, hands and knives

Pork is the most commonly consumed meat in Vietnam, and Salmonella enterica is a common contaminant. This study aimed to assess potential S. enterica cross-contamination between raw and cooked pork in Vietnamese households. Different scenarios for cross-contamination were constructed based on a household survey of pork handling practices (416 households). Overall, 71% of people used the same knife and cutting board for both raw and cooked pork; however, all washed their hands and utensils between handling raw and cooked pork. The different scenarios were experimentally tested. First, S. enterica was inoculated on raw pork and surfaces (hands, knives and cutting boards); next, water used for washing and pork were sampled to identify the presence and concentration of S. enterica during different scenarios of food preparation. Bootstrapping techniques were applied to simulate transfer rates of S. enterica cross-contamination. No cross-contamination to cooked pork was observed in the scenario of using the same hands with new cutting boards and knives. The probability of re-contamination in the scenarios involving re-using the cutting board after washing was significantly higher compared to the scenarios which used a new cutting board. Stochastic simulation found a high risk of cross-contamination from raw to cooked pork when the same hands, knives and cutting boards were used for handling raw and cooked pork (78%); when the same cutting board but a different knife was used, cross-contamination was still high (67%). Cross-contamination between was not seen when different cutting boards and knives were used for cutting raw and cooked pork. This study provided an insight into cross-contamination of S. enterica, given common food handling practices in Vietnamese households and can be used for risk assessment of pork consumption.

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Cross-Contamination and Transfer Rates of Bacteria on the Cutting Boards

Journal of Food Science and Engineering ◽

10.17265/2159-5828/2012.09.069 ◽

2012 ◽

Vol 2 (9) ◽

Author(s):

Michiru Kishimoto ◽

Chiaki Kojima ◽

Ayaka Maeda ◽

Ayako Morinaga

Keyword(s):

Cross Contamination ◽

Transfer Rates ◽

Cutting Boards

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Quantification of cross-contamination of Campylobacter jejuni during food preparation in a model kitchen in China

Journal of Food Protection ◽

10.4315/jfp-20-280 ◽

2020 ◽

Author(s):

Yao Bai ◽

Xiao-Hui Lin ◽

Jiang-Hui Zhu ◽

Sheng-Hui Cui ◽

Li-Xia Guo ◽

...

Keyword(s):

Campylobacter Jejuni ◽

Cold Water ◽

Scientific Evidence ◽

Hot Water ◽

Cross Contamination ◽

Case Control Studies ◽

Food Handling ◽

Transfer Rates ◽

The Cross ◽

Cutting Boards

Numerous outbreak investigations and case-control studies of campylobacteriosis have provided evidence that handling Campylobacter -contaminated chicken products is a high risk factor for infection and illness. In this study, the cross-contamination and transfer rates of Campylobacter jejuni from chicken to ready-to-eat foods were determined in various food-handling scenarios. Skinless raw chicken breasts were artificially contaminated with Campylobacter jejuni and diced on three kinds of texture cutting boards. Whether cold water or cold water with detergent or hot water was used, statistically significant differences were found between the transfer rate of Campylobacter jejuni to unwashed and washed cutting boards or hands, respectively. When both kitchen knife and cutting board were reused after dicing the artificially contaminated chicken, the transfer rates of Campylobacter jejuni to cucumber cut on bamboo, wooden and plastic cutting board were 16.28%, 12.82% and 5.32%, respectively. The transfer rates from chicken to bread, a large lift-up water faucet handle and a small twist faucet handle via unwashed hands were 0.49%, 4.64% and 3.14%, respectively. This research provides scientific evidence that various types of contaminated kitchen-ware and cook’s hand are vital potential vehicles for the cross-contamination of Campylobacter from raw chicken to ready-to-eat food, and emphasizes the importance of timely and properly cleaning to prevent cross-contamination during food handling, therefore a high quality consumer education to reduce the risk of foodborne infection is urgent and necessary.

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Transfer of Salmonella enterica Serovar Typhimurium from Beef to Tomato through Kitchen Equipment and the Efficacy of Intermediate Decontamination Procedures

Journal of Food Protection ◽

10.4315/0362-028x.jfp-15-531 ◽

2016 ◽

Vol 79 (7) ◽

pp. 1252-1258 ◽

Cited By ~ 6

Author(s):

E. GKANA ◽

A. LIANOU ◽

G.-J. E. NYCHAS

Keyword(s):

Foodborne Pathogens ◽

Salmonella Enterica ◽

Fruits And Vegetables ◽

Salmonella Enterica Serovar Typhimurium ◽

Tap Water ◽

Pathogenic Microorganisms ◽

Cross Contamination ◽

Raw Meat ◽

Serovar Typhimurium ◽

Cutting Boards

ABSTRACT It is well established that a high percentage of foodborne illness is caused by failure of consumers to prepare food in a hygienic manner. Indeed, a common practice in households is to use the same kitchen equipment for both raw meat and fresh produce. Such a practice may lead to cross-contamination of fruits and vegetables, which are mainly consumed without further processing, with pathogenic microorganisms originating from raw meat. The present study was performed to examine the transfer of the pathogenic bacterium Salmonella enterica serovar Typhimurium from inoculated beef fillets to tomatoes via contact with high-density polyethylene (PE), stainless steel (SS), and wooden (WD) surfaces and through cutting with SS knives. Furthermore, the following decontamination procedures were applied: (i) rinsing with tap water, (ii) scrubbing with tap water and liquid dish detergent, and (iii) using a commercial antibacterial spray. When surfaces and knives that came into contact with contaminated beef fillets were not cleaned prior to handling tomatoes, the lowest level of pathogen transfer to tomatoes was observed through PE surfaces. All of the decontamination procedures applied were more effective on knives than on surfaces, while among the surface materials tested, WD surfaces were the most difficult to decontaminate, followed by PE and SS surfaces. Mechanical cleaning with tap water and detergent was more efficient in decontaminating WD surfaces than using commercial disinfectant spray, followed by rinsing only with water. Specifically, reductions of 2.07 and 1.09 log CFU/cm2 were achieved by washing the WD surfaces with water and detergent and spraying the surfaces with an antibacterial product, respectively. Although the pathogen's populations on SS and PE surfaces, as well as on tomatoes, after both aforementioned treatments were under the detection limit, the surfaces were all positive after enrichment, and thus, the potential risk of cross-contamination cannot be overlooked. As demonstrated by the results of this study, washing or disinfection of kitchen equipment may not be sufficient to avoid cross-contamination of ready-to-eat foods with foodborne pathogens, depending on the decontamination treatment applied and the material of the surfaces treated. Therefore, separate cutting boards and knives should be used for processing raw meat and preparing ready-to-eat foods in order to enhance food safety.

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Quantification and Variability Analysis of Bacterial Cross-Contamination Rates in Common Food Service Tasks

Journal of Food Protection ◽

10.4315/0362-028x-64.1.72 ◽

2001 ◽

Vol 64 (1) ◽

pp. 72-80 ◽

Cited By ~ 201

Author(s):

YUHUAN CHEN ◽

KRISTIN M. JACKSON ◽

FABIOLA P. CHEA ◽

DONALD W. SCHAFFNER

Keyword(s):

Food Service ◽

Enterobacter Aerogenes ◽

Scientific Basis ◽

Food Preparation ◽

Contamination Rate ◽

Cross Contamination ◽

Transfer Rates ◽

Washing Efficiency ◽

The Cross ◽

Contamination Events

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.

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Quantification of Campylobacter Species Cross-Contamination during Handling of Contaminated Fresh Chicken Parts in Kitchens

Applied and Environmental Microbiology ◽

10.1128/aem.72.1.66-70.2006 ◽

2006 ◽

Vol 72 (1) ◽

pp. 66-70 ◽

Cited By ~ 106

Author(s):

Petra Luber ◽

Sigrid Brynestad ◽

Daniela Topsch ◽

Kathrin Scherer ◽

Edda Bartelt

Keyword(s):

Risk Assessments ◽

Chicken Breast ◽

Cross Contamination ◽

Case Control Studies ◽

Transfer Rates ◽

Colony Counting ◽

Outbreak Investigations ◽

The Mean ◽

Bread Roll ◽

Cooked Meat

ABSTRACT Numerous outbreak investigations and case-control studies for campylobacteriosis have provided evidence that handling Campylobacter-contaminated chicken products is a risk factor for infection and illness. There is currently extremely limited quantitative data on the levels of Campylobacter cross-contamination in the kitchen, hindering risk assessments for the pathogen commodity combination of Campylobacter and chicken meat. An exposure assessment needs to quantify the transfer of the bacteria from chicken to hands and the kitchen environment and from there onto ready-to-eat foods. We simulated some typical situations in kitchens and quantified the Campylobacter transfer from naturally contaminated chicken parts most commonly used in Germany. One scenario simulated the seasoning of five chicken legs and the reuse of the same plate for cooked meat. In another, five chicken breast filets were cut into small slices on a wooden board where, without intermediate cleaning, a cucumber was sliced. We also investigated the transfer of the pathogen from chicken via hands to a bread roll. The numbers of Campylobacter present on the surfaces of the chicken parts, hands, utensils, and ready-to-eat foods were detected by using Preston enrichment and colony counting after surface plating on Karmali agar. The mean transfer rates from legs and filets to hands were 2.9 and 3.8%. The transfer from legs to the plate (0.3%) was significantly smaller (P < 0.01) than the percentage transferred from filets to the cutting board and knife (1.1%). Average transfer rates from hands or kitchen utensils to ready-to-eat foods ranged from 2.9 to 27.5%.

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Simulation of Cross-Contamination and Decontamination of Campylobacter jejuni during Handling of Contaminated Raw Vegetables in a Domestic Kitchen

Journal of Food Protection ◽

10.4315/0362-028x-71.12.2448 ◽

2008 ◽

Vol 71 (12) ◽

pp. 2448-2452 ◽

Cited By ~ 24

Author(s):

LAY-CHING CHAI ◽

HAI-YEN LEE ◽

FARINAZLEEN MOHD GHAZALI ◽

FATIMAH ABU BAKAR ◽

PRADEEP KUMAR MALAKAR ◽

...

Keyword(s):

Campylobacter Jejuni ◽

Tap Water ◽

Hot Water ◽

Wash Water ◽

Most Probable Number ◽

Cross Contamination ◽

Probable Number ◽

Transfer Rates ◽

Log Reduction ◽

Potential Risk Factors

Campylobacter jejuni was found to occur at high prevalence in the raw salad vegetables examined. Previous reports describe cross-contamination involving meat; here we investigated the occurrence of cross-contamination and decontamination events in the domestic kitchen via C. jejuni–contaminated vegetables during salad preparation. This is the first report concerning quantitative cross-contamination and decontamination involving naturally contaminated produce. The study was designed to simulate the real preparation of salad in a household kitchen, starting with washing the vegetables in tap water, then cutting the vegetables on a cutting board, followed by slicing cucumber and blanching (heating in hot water) the vegetables in 85° water. Vegetables naturally contaminated with C. jejuni were used throughout the simulation to attain realistic quantitative data. The mean of the percent transfer rates for C. jejuni from vegetable to wash water was 30.1 to 38.2%; from wash water to cucumber, it was 26.3 to 47.2%; from vegetables to cutting board, it was 1.6 to 10.3%; and from cutting board to cucumber, it was 22.6 to 73.3%. The data suggest the wash water and plastic cutting board as potential risk factors in C. jejuni transmission to consumers. Washing of the vegetables with tap water caused a 0.4-log reduction of C. jejuni attached to the vegetables (most probable number/gram), while rapid blanching reduced the number of C. jejuni organisms to an undetectable level.

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Assessing the cross contamination and transfer rates of Salmonella enterica from chicken to lettuce under different food-handling scenarios

Food Microbiology ◽

10.1016/j.fm.2010.04.011 ◽

2010 ◽

Vol 27 (6) ◽

pp. 791-794 ◽

Cited By ~ 49

Author(s):

Sadhana Ravishankar ◽

Libin Zhu ◽

Divya Jaroni

Keyword(s):

Salmonella Enterica ◽

Cross Contamination ◽

Food Handling ◽

Transfer Rates ◽

The Cross

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Kitchen Practices Used in Handling Broiler Chickens and Survival of Campylobacter spp. on Cutting Surfaces in Kampala, Uganda

Journal of Food Protection ◽

10.4315/0362-028x-67.9.1957 ◽

2004 ◽

Vol 67 (9) ◽

pp. 1957-1960 ◽

Cited By ~ 13

Author(s):

IRENE WANYENYA ◽

CHARLES MUYANJA ◽

GEORGE WILLIAM NASINYAMA

Keyword(s):

Fast Food ◽

Broiler Chickens ◽

Metal Cutting ◽

Food Preparation ◽

Cross Contamination ◽

Street Vendors ◽

Microbiological Methods ◽

Handling Practices ◽

Cutting Boards ◽

Campylobacter Spp

Cross-contamination during food preparation has been identified as an important factor associated with foodborne illnesses. Handling practices used during preparation of broiler chickens in 31 fast-food restaurants and 86 semisettled street stands (street vendors) were assessed by use of a standard checklist. These establishments used wood, plastic, or metal cutting surfaces during the preparation of broiler chickens. The survival of Campylobacter spp. on kitchen cutting surfaces was determined by inoculating approximately 106 CFU of Campylobacter jejuni onto sterile plastic, wooden, and metal cutting boards. The concentrations of the organisms were then assessed in triplicate on each type of cutting board over a 3-h period using standard microbiological methods for thermophilic Campylobacter spp. In 87% of food establishments, the same work area was used for preparation of raw and cooked chicken, and in 68% of these establishments the same cutting boards were used for raw and cooked chicken. None of the establishments applied disinfectants or sanitizers when washing contact surfaces. Campylobacter spp. survived on wooden and plastic but not on metal cutting boards after 3 h of exposure. The handling practices in food preparation areas, therefore, provide an opportunity for cross-contamination of Campylobacter spp. to ready-to-eat foods.

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Influence of suspension liquid total solids on E. coli O157:H7 survival and transfer efficacy between green tomatoes and cardboard

Potravinarstvo Slovak Journal of Food Sciences ◽

10.5219/1210 ◽

2019 ◽

Vol 13 (1) ◽

pp. 941-949

Author(s):

Oleksandr Tokarskyy ◽

Mykhaylo Korda

Keyword(s):

Transfer Rate ◽

Positive Transfer ◽

Post Inoculation ◽

Cross Contamination ◽

Organic Residues ◽

Hydrophobic Properties ◽

Transfer Rates ◽

E Coli ◽

Hygroscopic Nature ◽

Peptone Water

The objectives of this study were: a) to determine E. coli O157:H7 survival on tomatoes and cardboard squares post-drying, stored at 25 ºC in humidified environment for four days, in buffered peptone water (BPW), and 0.1% diluted peptone (DP); b) to determine pathogen transfer rates (0, 1.5, or 24-hours drying post-inoculation), from inoculated tomato surfaces to uninoculated cardboard squares and conversely; and c) to evaluate SystemSure Plus ATP luminometer for recognizing contamination on visibly soiled (BPW) or visible clean (DP) cardboard. In tomato inoculation studies, E. coli O157:H7 survived better on the fruit when the inoculum was prepared using DP as compared to BPW. The 1.5-hours post drying counts of 5.34 and 5.76 log10 CFU.mL-1 in the rinsate substantially declined to 1.45 and 1.17 log10 CFU.mL-1 on day four, for DP and BPW, respectively. In cardboard inoculation studies, E. coli O157:H7 persisted for four days, with 1.5-hours post-drying counts and day four counts of 4.53 (DP) and 2.55 log10 CFU.mL-1 (BPW), contrary to 3.81 (DP) and 1.92 log10 CFU.mL-1 (BPW). Under the first impression, the slower die-off of E. coli O157:H7 on cardboard questions the possibility of reusing cardboard boxes due to the potential for cross-contamination. In wet transfer (0 hour drying) trials, both tomato-to-cardboard and cardboard-to-tomato yielded 100% positive transfers irrespective of diluent type. Dry transfer (1.5-hours drying interval post inoculation) from tomato-to-cardboard were 100% positive, but no positives were noted when inoculated, dried cardboard was contacted to tomatoes, irrespective of diluent. Results of transfers with BPW as the diluent showed 100% positive transfer from 24-hours dry tomatoes-to-cardboard, as inoculation spots on the tomatoes remained moist due to hygroscopic nature of solutes in BPW. Conversely, only a 40% positive transfer rate was observed under the same conditions with DP as diluent. No positive transfers were recorded from 24-hours dry cardboard-to-tomatoes, irrespective of diluent type. Though E. coli O157:H7 survived better on the surface of cardboard compared to the surface of tomatoes on day four, the dry transfers were more efficient from tomatoes-to-cardboard than conversely, possibly due to smooth and hydrophobic properties of the tomato, and rough and porous surface of the cardboard. ATP luciferase UltrasnapTM swab test showed 9/9 “pass” results for sterile liquid DP and BPW, while 9/9 “fail” results were observed with liquid peptone and BPW contaminated at ca. 9.0 log10 CFU.mL-1 E. coli O157:H7. Cardboard squares treated and dried, with sterile DP, showed 8/9 “pass” ATP luciferase results, and 1/9 “warning”, while cardboard squares with contaminated DP showed 9/9 “fail” result. Cardboard squares treated and dried, with sterile BPW, showed 7/9 “pass” ATP luciferase results, and 2/9 “warning”, while cardboard squares with contaminated BPW showed 9/9 “fail” result. Luminometer can simplify detection of microbial load, as well as organic residues, helping to check cardboard boxes for cleanness.

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