Adequate Hand Washing and Glove Use Are Necessary To Reduce Cross-Contamination from Hands with High Bacterial Loads

2016 ◽  
Vol 79 (2) ◽  
pp. 304-308 ◽  
Author(s):  
ANDREW L. ROBINSON ◽  
HYUN JUNG LEE ◽  
JUNEHEE KWON ◽  
EWEN TODD ◽  
FERNANDO PEREZ RODRIGUEZ ◽  
...  
Keyword(s):  
Food Service ◽  
Enterobacter Aerogenes ◽  
Hand Washing ◽  
Cross Contamination ◽  
Bacterial Reduction ◽  
Bacterial Counts ◽  
Transfer Rates ◽  
Service Setting ◽  
Service Environments

ABSTRACT Hand washing and glove use are the main methods for reducing bacterial cross-contamination from hands to ready-to-eat food in a food service setting. However, bacterial transfer from hands to gloves is poorly understood, as is the effect of different durations of soap rubbing on bacterial reduction. To assess bacterial transfer from hands to gloves and to compare bacterial transfer rates to food after different soap washing times and glove use, participants' hands were artificially contaminated with Enterobacter aerogenes B199A at ~9 log CFU. Different soap rubbing times (0, 3, and 20 s), glove use, and tomato dicing activities followed. The bacterial counts in diced tomatoes and on participants' hands and gloves were then analyzed. Different soap rubbing times did not significantly change the amount of bacteria recovered from participants' hands. Dicing tomatoes with bare hands after 20 s of soap rubbing transferred significantly less bacteria (P < 0.01) to tomatoes than did dicing with bare hands after 0 s of soap rubbing. Wearing gloves while dicing greatly reduced the incidence of contaminated tomato samples compared with dicing with bare hands. Increasing soap washing time decreased the incidence of bacteria recovered from outside glove surfaces (P < 0.05). These results highlight that both glove use and adequate hand washing are necessary to reduce bacterial cross-contamination in food service environments.

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

2001 ◽  
Vol 64 (1) ◽  
pp. 72-80 ◽  
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.

Linking Quantitative Exposure Assessment and Risk Management Using the Food Safety Objective Concept: An Example with Listeria monocytogenes in Different Cross-Contamination Scenarios

2006 ◽  
Vol 69 (10) ◽  
pp. 2384-2394 ◽  
Author(s):  
F. PÉREZ-RODRÍGUEZ ◽  
E. C. D. TODD ◽  
A. VALERO ◽  
E. CARRASCO ◽  
R. M. GARCÍA ◽  
...  
Keyword(s):  
Risk Management ◽  
Listeria Monocytogenes ◽  
Food Safety ◽  
Hand Washing ◽  
Cross Contamination ◽  
Transfer Rates ◽  
Management Interventions ◽  
Scenarios Analysis ◽  
Washing Method ◽  
Risk Managers

A practical approach was used to achieve specified food safety objectives (FSOs) by incorporating risk assessment methodology. A series of cross-contamination scenarios at the retail level were evaluated in a spreadsheet and ranked according to their level of risk, and the degree to which they exceeded an FSO for Listeria monocytogenes (100 CFU/g) was determined. Percentiles and analyses of variance were used to identify which scenarios would be most likely not to achieve the FSO. It was also possible to incorporate into the model the effect of additional risk management interventions (e.g., hand washing method) by using “what if” scenarios analysis. The highest risk corresponded to the use of the same gloves to handle contaminated meat and then sliced ham compared with the safer method of using different gloves to handle each product. Nevertheless, in all scenarios bacterial concentrations could be higher than 108 CFU/g. A significant lack of knowledge regarding the transfer rates of L. monocytogenes was revealed, which provided the model with an important uncertainty component. The “what if” scenarios analysis based on the scenario representing handling food with bare hands followed by hand washing (scenario 2) revealed that the hand washing procedure had less impact than expected. This study illustrates the use of scenarios to model the most effective food processes and thus provide risk managers with appropriate information on which to base their decisions.

Quantifying Bacterial Cross-Contamination Rates between Fresh-Cut Produce and Hands

2017 ◽  
Vol 80 (2) ◽  
pp. 213-219 ◽  
Author(s):  
Dane A. Jensen ◽  
Michelle D. Danyluk ◽  
Linda J. Harris ◽  
Donald W. Schaffner
Keyword(s):  
Bacterial Species ◽  
Enterobacter Aerogenes ◽  
Escherichia Coli O157 ◽  
Cross Contamination ◽  
Transfer Rates ◽  
E Coli ◽  
Significant Difference ◽  
Fresh Cut ◽  
Food Safety Risk ◽  
Risk Assessment And Management

ABSTRACT This study quantifies the cross-contamination rates between fresh-cut produce and hands using a nalidixic acid–resistant nonpathogenic Enterobacter aerogenes and cocktails of rifampin-resistant Salmonella or Escherichia coli O157:H7 strains. Volunteers performed the E. aerogenes experiments (n = 20), and one of the authors performed the Salmonella and E. coli O157:H7 experiments multiple times (n =15 and n =10, respectively). Each participant handled 25 g of fresh-cut carrots, celery, or cantaloupe in two different scenarios. In the first scenario, gloved hands were inoculated with 6 log CFU per hand of the bacteria, and in the second scenario, five 25-g pieces of fresh produce were inoculated to a concentration of 6 log CFU/25 g. The glove juice method was used to quantify the bacterial concentration on the gloved hands. About 30% of E. aerogenes on gloved hands was transferred to the carrots and celery, and 18% of E. aerogenes on gloved hands was transferred to the cantaloupe. When carrots or cantaloupe was inoculated with E. aerogenes, 1% was transferred to gloved hands; from inoculated celery, about 0.3% of E. aerogenes was transferred to gloved hands. There was not a significant difference between E. aerogenes and Salmonella cross-contamination rates (P > 0.05). When gloved hands were contaminated with E. coli O157:H7, about 30% was transferred to carrots, about 10% to celery, and about 3% to cantaloupe. When carrots and celery were inoculated with E. coli O157:H7, about 1% was transferred to gloved hands, but from inoculated cantaloupe only about 0.3% was transferred. Direction of transfer (to versus from produce), difference in type of produce, and differences among the bacterial species all had significant effects on the transfer rate. Understanding transfer rates to and from fresh-cut produce will allow for better risk assessment and management of microbial food safety risk related to fresh-cut produce.

Glove Barriers to Bacterial Cross-Contamination between Hands to Food

2001 ◽  
Vol 64 (6) ◽  
pp. 845-849 ◽  
Author(s):  
REBECCA MONTVILLE ◽  
YUHUAN CHEN ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Nalidixic Acid ◽  
Transfer Rate ◽  
Microbial Contamination ◽  
Enterobacter Aerogenes ◽  
Published Data ◽  
Cross Contamination ◽  
Transfer Rates ◽  
Transfer Data ◽  
High Inoculum ◽  
Bare Hand

Human hands are an important source of microbial contamination of foods. However, published data on the effectiveness of handwashing and glove use in a foodservice setting are limited. Bacterial transfer through foodservice quality gloves was quantified using nalidixic acid-resistant Enterobacter aerogenes (a nonpathogenic surrogate with attachment characteristics similar to Salmonella). Five transfer rates were determined: chicken to bare hand, chicken to hand through gloves, bare hand to lettuce, hand to lettuce through gloves (with low inoculum on hands), and hand to lettuce through gloves (with high inoculum on hands). At least 30 observations were made for each percent transfer rate using 30 individual volunteers. The logarithm of percent transfer data were then fit to distributions: chicken to bare hand, normal (0.71, 0.42); chicken to hand through gloves, gamma (5.91, 0.40, −5.00); bare hand to lettuce, logistic (1.16, 0.30); hand to lettuce through gloves (low inoculum), normal (0.35, 0.88); hand to lettuce through gloves (high inoculum), normal (−2.52, 0.61). A 0.01% transfer was observed from food to hands and from hands to food when subjects wore gloves and a 10% transfer was observed without a glove barrier. These results indicate that gloves are permeable to bacteria although transfer from hands to food through a glove barrier was less than without a glove barrier. Our results indicate that gloves may reduce both bacterial transfer from food to the hands of foodservice workers and in subsequent transfer from hands back to food.

scholarly journals Cross-Contamination on Atypical Surfaces and Venues in Food Service Environments

2021 ◽  
Author(s):  
Rebecca Goulter ◽  
Margaret Kirchner ◽  
Benjamin Chapman ◽  
James S. Clayton ◽  
Lee-Ann Jaykus
Keyword(s):  
Foodborne Pathogens ◽  
Food Service ◽  
Foodborne Illness ◽  
Cross Contamination ◽  
The Past ◽  
Food Contact Surfaces ◽  
Contact Surfaces ◽  
To Come ◽  
Service Environments

Cross-contamination of raw food to other surfaces, hands, and foods is a serious issue in foodservice.  With individuals eating more meals away from home, contracting a foodborne illness from a food service establishment is an increasing concern.  However, most studies have concentrated on hands or food contact surfaces and neglected atypical and unusual surfaces (surfaces that are not typically identified as a source of cross-contamination) and venues.  This review seeks to identify atypically cross-contaminated surfaces and atypical venues where cross-contamination could occur that have not been examined thoroughly in the literature.  Most surfaces that could be at risk for cross-contamination are frequently touched, rarely cleaned and sanitized, and can support the persistence and/or growth of foodborne pathogens.  These surfaces include, menus, spice and condiment containers, aprons and coveralls, mobile devices and tablets, and currency, among others.  Venues that are explored, temporary events, mobile vendors, and markets, are usually limited in space or infrastructure, have low compliance to proper handwashing, and provide the opportunity for raw and RTE foods to come into contact with one another. These factors all create an environment where cross-contamination can occur and potentially impact food safety.  A more comprehensive cleaning sanitizing regime encompassing these surfaces and venues could potentially help mitigate the cross-contamination described here.  This review highlights key surfaces and venues that have the potential to be cross-contaminated that have been underestimated in the past or are not fully explored in the literature.  These knowledge gaps demonstrate where further work is need to fully understand the role of these surfaces and venues in cross-contamination and how it can be prevented in the future.

scholarly journals Methods for cleaning & sanitizing food contact surfaces (countertops) to prevent cross contamination in restaurant kitchens

2017 ◽  
Author(s):  
Laura Matthewson ◽  
BCIT School of Health Sciences, Environmental Health ◽  
Helen Heacock
Keyword(s):  
Environmental Health ◽  
Food Service ◽  
Cross Contamination ◽  
Bacterial Reduction ◽  
Step Method ◽  
Cleaning Method ◽  
Food Contact ◽  
Health Officer ◽  
Food Contact Surfaces ◽  
Contact Surfaces

  Background: Cross contamination can occur in restaurant kitchens when food contact surfaces such as countertops are inadequately cleaned between preparation of raw and ready to eat foods. Previous research has demonstrated that washing with detergent and water, rinsing, then applying a sanitizer solution is the most effective cleaning method. The second most effective cleaning method is to use detergent and water alone. In practice, the author has observed kitchen staff using sanitizer alone to clean kitchen countertops. This study surveyed British Columbia restaurant kitchen staff on current practices and makes recommendations to improve cleaning and sanitization practices for the purpose of preventing cross contamination. Methods: A survey was prepared using SurveyMonkey and distributed through Facebook to the author’s contacts in the restaurant industry. The Facebook post included a request for anyone to share the survey link with their contacts who work in BC restaurant kitchens. The survey was shared 21 times by 14 different people. The survey asked questions about restaurant type and position, Foodsafe level, and about cleaning practices such as frequency and cleaning compounds used. Results: When asked what cleaning compounds are most often used to clean work surfaces (countertops) in their restaurant, 56.5% of respondents reported sanitizer solution only, 30.4% of respondents reported soap & water followed by sanitizer solution, and 13.0% reported soap and water only. When asked why sanitizer solution only was used to clean countertops, 46.2% of respondents said it was company policy, 23.1% of respondents said time savings, and 15.4% of respondents indicated that an Environmental Health Officer had recommended sanitizer use and that is what lead to sanitizer alone being used to clean countertops. Conclusions: In practice, some restaurant staff do not use sanitizer effectively and may believe it is a substitute for detergent. Using sanitizer alone is not as effective as using detergent alone. Detergent alone can provide a 2-3 log bacterial reduction. If staff are busy and are only going to use one cleaning step, detergent alone is the best method. Environmental Health Officers should review sanitation plans and talk with operators to determine current cleaning practices in food service establishments. Operators and staff should be re-educated on the importance of the three-step method. It may be beneficial to recommend that sanitizer use be decreased overall to encourage the use of soap and water. It may only be necessary to use sanitizer after high-risk jobs such as preparing raw meat or at the end of the day.  

Hand Washing Frequencies and Procedures Used in Retail Food Services

2008 ◽  
Vol 71 (8) ◽  
pp. 1641-1650 ◽  
Author(s):  
CATHERINE STROHBEHN ◽  
JEANNIE SNEED ◽  
PAOLA PAEZ ◽  
JANELL MEYER
Keyword(s):  
Assisted Living ◽  
Service Industry ◽  
Food Service ◽  
The Elderly ◽  
Hand Washing ◽  
Assisted Living Facilities ◽  
Food Services ◽  
Managerial Control ◽  
Lost Productivity ◽  
Retail Food

Transmission of viruses, bacteria, and parasites to food by way of improperly washed hands is a major contributing factor in the spread of foodborne illnesses. Field observers have assessed compliance with hand washing regulations, yet few studies have included consideration of frequency and methods used by sectors of the food service industry or have included benchmarks for hand washing. Five 3-h observation periods of employee (n = 80) hand washing behaviors during menu production, service, and cleaning were conducted in 16 food service operations for a total of 240 h of direct observation. Four operations from each of four sectors of the retail food service industry participated in the study: assisted living for the elderly, childcare, restaurants, and schools. A validated observation form, based on 2005 Food Code guidelines, was used by two trained researchers. Researchers noted when hands should have been washed, when hands were washed, and how hands were washed. Overall compliance with Food Code recommendations for frequency during production, service, and cleaning phases ranged from 5% in restaurants to 33% in assisted living facilities. Procedural compliance rates also were low. Proposed benchmarks for the number of times hand washing should occur by each employee for each sector of food service during each phase of operation are seven times per hour for assisted living, nine times per hour for childcare, 29 times per hour for restaurants, and 11 times per hour for schools. These benchmarks are high, especially for restaurant employees. Implementation would mean lost productivity and potential for dermatitis; thus, active managerial control over work assignments is needed. These benchmarks can be used for training and to guide employee hand washing behaviors.

scholarly journals Simulating Cross-Contamination of Cooked Pork with Salmonella enterica from Raw Pork through Home Kitchen Preparation in Vietnam

2018 ◽  
Vol 15 (10) ◽  
pp. 2324 ◽  
Author(s):  
Sinh Dang-Xuan ◽  
Hung Nguyen-Viet ◽  
Phuc Pham-Duc ◽  
Delia Grace ◽  
Fred Unger ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Household Survey ◽  
Cross Contamination ◽  
Food Handling ◽  
Transfer Rates ◽  
Handling Practices ◽  
Food Handling Practices ◽  
Cutting Boards ◽  
Insight Into ◽  
Pork Consumption

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.

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

2006 ◽  
Vol 72 (1) ◽  
pp. 66-70 ◽  
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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