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Hygiene issues associated with food service potholders and oven mitts
Abstract
Food service kitchen oven mitts and potholders are indispensable forms of personal protective equipment (PPE). As mitts and potholders are often contaminated with both raw and cooked food soils that support microbial survival and growth, it has been suggested that they present a possible risk to food safety. To ascertain the extent to which these items might contribute to cross-contamination, 10 dirty oven mitts and 3 dirty potholders obtained from a variety of establishments in the US were surveyed for microbial populations. Aerobic plate counts (APC) as high as 7 × 106 colony forming units (CFU) were found on outer surfaces. Potholders taken from a hospital kitchen were found to have approximately 106 CFU coliforms and B. cereus. Overall, samples examined were seen to have high coliform, B. cereus, and Pseudomonas spp. counts with occasional C. perfringens found. Interior surfaces of mitts, while lower than exterior (geometric mean APC 1.2 × 105 versus 6.0 × 104), were also found to be contaminated with S. aureus. While no E. coli, Listeria spp. or Salmonella spp. were found, indications are that food service PPE offering thermal protection can become contaminated and may, in turn, contaminate hands and food, unless frequently cleaned or sanitized.
... Use of barriers to transmission such as deli papers, utensils or gloves have differing efficacies and limitations with respect to risk reduction. Various types of gloves are employed in the food industry to protect the food worker from occupational exposures related to food product or process, as well as prevent pathogen or spoilage organism transmission in the other direction from the worker to the product (London et al. 1992; Lund et al. 2000; Michaels 2001a; Michaels et al. 2002b). No reports of deli or bakery paper failure to prevent transmission are known to exist, whereas utensils are commonly associated with hygiene failures (Bryan 1978; Bryan 1988; Bean & Griffin 1990; Bean et al. 1996; Olsen et al. 2000). ...
... ry and infection control agencies use similar approaches. Filtration is used for enumeration of bacteria in water. Swabs are taken from different surfaces to assess the effectiveness of hygienic practices including cleaning. For example, the critical areas harbouring pathogens were personal protective equipment including oven mitts and potholders (Michaels et al . 2002). Floor mats and footbaths were contaminated with L. monocytogenes , a pathogen of particular significance in cook-chill processing (Klausner & Donnelly 1991). Surfaces can be inoculated or challenged with an indicator organism, subjected to cleaning and then swabbed. Meredith et al . (2001) used this approach to study the potential spr ...
Food service systems allow the decoupling of food production from service and offer economies of scale. However, the multiple steps in processing introduce additional safety risks in comparison with the traditional preparation. Operators need to be aware of the preservation principles and the type of data available in food safety research. This paper provides justification and describes the link between different types of studies in the field: surveys of background microflora, challenge studies, food safety design, predictive modelling, hazard analysis critical control point (HACCP) and good manufacturing practices (GMP). The needs and directions for further research are identified.
R eliably producing food product involves full knowledge and con-trol of process hazards. 1 Employing statistical process controls to keep time and temperature, viscosity and other physical prop-erties within upper and lower standard limits means that the processes are considered centerlined. With the food production line or food serv-ice operation running smoothly within acceptable statistical parameters, management can feel that the process is under control. 2 Don't be fooled. There are out-of-control elements giving you a false sense of security that are potentially damaging to your process. I'm talking about food-handling gloves. The proper use of gloves in food processing and food service is predicated on the maintenance of glove integrity. 3 Faith is placed in gloves to satisfy the twin safety objectives of protecting workers and preventing food product contamination at a rea-sonable cost. This is accomplished by keeping food soils and hazards associated with such soils or residues off of workers' skin (hands), and more importantly, by keeping potential human pathogens associated with workers and their hands out of food. 4 By definition, glove failure is a deviation away from intended control limits; oth-erwise, bare hands would be the norm. Foodborne pathogens reside within a variety of reservoirs, the raw food, food workers themselves, the food worker's hands, the food worker's family, etc. Risk is only reduced by frequent, appropriate and effective appli-cation hygiene measures, mindful of the potential for recontamination. The uses of barriers to transmission such as deli papers, utensils or gloves all have differing effica-cies and limitations with respect to risk reduction. Various types of gloves are employed in the food industry, both to protect the food worker from occupational exposures related to food product or process, as well to prevent pathogen or spoilage organism transmission in from the worker to the product. 3-6 TO GLOVE OR NOT TO GLOVE Hand hygiene means different things to different people. Some food workers think that it means just rinsing hands under the faucet, while other workers know enough to wash, rinse and dry. 7 We know that usu-ally less than 50% of food workers wash when necessary. A recent UK Food Standards Agency survey showed that one-third of caterers fail to wash hands after using the toilet. 8 Efficacy of a thor-ough hand washing sequence using antimicrobial soap, lathering well, rins-ing and drying may be greater than 3-log reduction (99.9%). Combined with alco-hol sanitizer treatment this can be raised even further. For example, long ago it was shown that Salmonella spp. can sur-vive for several hours on fingertips, but that handwashing followed by hand dry-ing with paper towels effectively reduced the risk of transmission to food. 9 If it were only that simple. There are impor-tant parts of the hand that are typically missed during the hand washing process. Thumbs, palms, spaces between fingers and fingertips, including the fingernail area, are areas where contamination is most likely to remain. The nail region presents special problems because more than 95% of hand flora resides in these areas. 10 Toilet paper poke-through results in fecal contamination of this part of the hand, commonly used hand hygiene protocols render this intervention largely ineffective, thereby additionally requir-ing fingernail brush use. 11-13 It is uncer-tain what role that the fingernail region plays in foodborne transmission of human pathogens and depending on glove strength at finger tips, whether glove use would increase or decrease the probability of transmission, when the nail region is heavily contaminated. It is known, for example, that artificial nails are linked to poor hand washing prac-tices, more glove tears and to out-breaks. 14-15 In gloves that trap heat and moisture, the potential exists to liquefy nail contamination and release it when punctured. This brings up the impor-tance of maintaining the glove barrier. Glove use has been proposed as a risk reduction strategy by public health authorities. 16-17 Even though gloves have also been shown to transfer or amplify risk, the U.S. FDA believes that hand-washing with soap and water or even use of alcohol hand sanitizers may not be enough to prevent transmission of viral and protozoan microorganisms via the Understanding the
The cleanliness of plates and dishes washed in two different types of machines was investigated. Both machines were one-tank dishwashers; one of them used water and detergent, the other used plastic granules, water and detergent as the cleaning medium. The mechanical effect of plastic granules, water and detergent cleaned the dishes better than water and detergent alone. For easily removed soil, as characterized in the international standards ANSI/NSF 3 and DIN 10512, both dishwashing machines resulted in clean dishes. Dishes covered with a more adhesive soil were clean only after washing in the granule-assisted washer. The importance of cleaning plates and dishes, in order to avoid cross-contamination and the spread of infection, is discussed.
Microorganisms have been frequently found in dishwaters despite high temperatures and pH levels. Therefore, this study investigates the dishwater in dishwashing processes to determine the survival rate of a heat-resistant test organism, Enterococcus faecium. The experiments are conducted in a 2-L beaker, and the temperature and the pH are varied in the spans typical for hand dishwashing and mechanical dishwashers (45–65C and pH 7–9). Tryptic soy is added to the beaker to study the influence of nutrition (which normally exists in dishwater). A three-log reduction of E. faecium after 50 min at 65C is noted and compared with 300 min at 55C, at pH 7. For 45C, no reduction of E. faecium is observed. The findings emphasize the importance of maintaining a high temperature in dishwaters during dishwashing processes.
The infected food handler can be responsible for the transmission of infectious intestinal diseases (IID) caused by foodborne pathogens. It is believed that personal hygiene practices with varying levels of complexity can help prevent foodborne pathogens from entering the food chain. Overall, it has been difficult to reach a consensus among stakeholders on precisely which intervention measures should be employed in food handling environments to effectively reduce IID rates. Through a study of over 300 reports of outbreaks attributed to ill or asymptomatic food handlers, hazards and contributory factors responsible for foodborne illness outbreaks were identified. With the use of the risk analysis software platforms of Analytica®, @Risk, and GoldSim®, models were created to explore measures of hygiene effectiveness. Through the use of appropriate models, results of various personal hygiene intervention measures were explored for the development of preventive management strategies, designed to improve food-handling practices at various levels of the food chain. These included exclusion of ill food handlers, vaccination for hepatitis A virus, handwashing combined with drying, wearing of gloves, and use of instant hand sanitizers and fingernail brushes. This was accomplished by modeling pathogen transfer and transmission routes from food handler via foods, beverages and common contact surfaces using GoldSim® and Monte Carlo simulations. A lottery model was also created to understand risk as an interrelated overlapping extremes driven system, comprised of the three components of hygiene frequency, efficacy and cross-contamination. Data gaps were identified with respect to areas where considerable variability and uncertainty exists in order to establish research priorities.
In response to continued concerns regarding Listeria cross-contamination during the slicing of deli meats, a series of specially prepared grade 304 and 316 stainless steel kitchen knife blades was inoculated with a six-strain Listeria monocytogenes cocktail (10(8), 10(5), and 10(3) CFU per blade) composed of two weak, two medium, and two strong biofilm-forming strains. The blades were then attached to an Instron 5565 electromechanical compression analyzer and used to slice whole chubs of delicatessen turkey breast, bologna, and salami to entirety (30 slices) at a cutting speed of 8.3 mm/s. Homogenates of the slices in University of Vermont Medium were surface or pour plated with modified Oxford agar and then enriched. Listeria transfer from knife blades inoculated at 10(8) CFU per blade was logarithmic, with a 2-log decrease seen after 8 to 12 slices and direct counts obtained thereafter out to 30 slices. However, blades containing 10(5) and 10(3) CFU per blade typically yielded direct counts out to only 20 and 5 slices, respectively. Normalizing data on a log scale for the first 10 slices resulted in significantly greater Listeria transfer and "tailing" from grade 304 as opposed to grade 316 stainless (P < 0.05) for all three products. After 1 year of use, surface roughness values as determined by surface profilometry were significantly greater (P < 0.001) for grade 304 than for grade 316 stainless blades. Cutting force and blade sharpness were not significantly different (P > 0.05) within stainless steel grade (P < 0.05) for each product. However, significant differences in cutting force were seen between salami and turkey (P < 0.05) for grades 304 and 316 stainless, respectively. In addition to compositional differences in the deli meats and knife blades, wear and scoring on the blade likely affected Listeria transfer during slicing.
Aeromonads deposited on pork during a carcass-breaking process were recovered on hydrophobic grid membrane filters placed on ampicillin-dextrin-ethanol agar. Isolates from 85 honey-yellow colonies from filters on that medium were Aeromonas hydrophila (95%) or Vibrio sp. (5%). Presumptive aeromonads, coliforms, and Escherichia coli in swab samples from product passing through a sheep carcass-breaking process were enumerated by hydrophobic grid membrane filtration techniques with a detection level of 1 CFU/100 cm2. Total aerobic counts were determined by a spread plate procedure with a detection level of 1 CFU/cm2 The numbers of aerobes, coliforms, and E. coli in the product were apparently unaffected by the carcass-breaking process, although coliforms and E. coli appeared to be redistributed from shoulder to loin and leg portions. However, the numbers of aeromonads on product increased by about two orders of magnitude as a result of the process. Few bacteria were recovered from most cleaned, large items of equipment, but aerobes, coliforms, and aeromonads were recovered at log total numbers of 5.25, 3.96, and 3.26, respectively, from most of 25 samples from bars supporting a conveyor belt. Also, aerobes, coliforms, E. coli, and aeromonads were recovered from 25 supposedly cleaned steel mesh gloves at log total numbers of 10.14, 5.54, 4.73, and 8.30, respectively. Those findings indicate that inspection of cleaned equipment and microbiological sampling of only food-contacting surfaces, as is the current practice at meat plants, cannot provide assurance that the cleaning of carcass-breaking equipment is adequate. Instead, enumeration of indicator organisms on product passing through a process seems to be required as well, with subsequent sampling of equipment to identify sources of contaminants if increases in numbers during processing are observed. For surety of adequate cleaning, enumeration of several types of indicator organism may be necessary, as increases during processing in the numbers of organisms that are present in relatively large numbers on product entering a process may be difficult to detect.
The mode of transmission of Staphylococcus saprophyticus, a urinary tract pathogen, was investigated in three related studies. The presence of this organism was sought, during a period of 1 year, in 1331 specimens of various foods, in 920 beef and pork carcasses and on 107 cultures which had been inoculated directly from abattoir workers' protective gloves. Staphylococcus saprophyticus was found to contaminate 16.4% of the various food samples with a high prevalence of 34% in raw beef and pork. It was common in both domestic and imported raw meat products. There was no seasonal variation in the presence of S. saprophyticus in the samples obtained from carcasses. The bacterium was found in 69% of all cultures from the workers' protective gloves. We conclude that S. saprophyticus, originating from slaughtered animals, contaminates food and eventually colonizes the human intestinal tract.
In a retrospective study carried out on about 730 patients with chronic renal failure who underwent ambulatory hemodialysis from January 1991 to June 1994, 49 patients were found to have developed acute hepatitis C, as confirmed by seroconversion for anti-HCV antibodies without blood transfusion in the preceding 6-month period. Epidemiological survey disclosed that two patients undergoing dialysis at consoles separated by one console developed acute hepatitis C in October 1992, and another three patients at adjacent consoles also developed acute hepatitis C within 2 weeks in April/May, 1993. It was found that some negligent nurses could have withdrawn needles from these patients one after another without changing gloves at the termination of the dialysis procedure. After reeducation of the staff members and introduction of a new type of adhesive pad to be placed on the needle wounds at the time of needle withdrawal, no new case of acute hepatitis C occurred for more than 1 year, suggesting nosocomial spread of HCV infection among hemodialysis patients in a mode that is preventable with very strict aseptic precautions.
One of the risks for contamination of edible product in the pre-inspection area of processing lines in meat plants is cross contamination. This can occur directly as a result of carcass-to-carcass contact or indirectly via knives or the hands of butchers. Standard procedures require that operators rinse their hands and knives to remove any visible contamination. In New Zealand, protective gloves are not allowed in the pre-inspection area because they are considered a potential risk for cross contamination until the carcasses have passed the final meat inspection. However, the risk of injury to the bare hands is as high in this area as in other parts of the plant, where such gloves are permitted. There is therefore a need to evaluate the risk of bacterial cross contamination via bare hands and via protective gloves. The present study compared bacterial adherence to bare hands and to gloves after rinsing for 5 s in a shower of water at 40 degrees C and after rinsing gloves in hotter water (60 degrees C) following simulated contact with the hide of a recently slaughtered animal. Under laboratory conditions there were no statistically significant differences between bacterial adherence to bare hands or to gloves rinsed in water at 40 degrees C or 60 degrees C.
We describe two cases of malaria occurring in a malaria-free zone in two in-patients, two weeks after a case of Plasmodium falciparum malaria, acquired in Burkina Faso, had been admitted to the same ward. After reviewing the techniques used by nursing staff, we conclude that transmission probably occurred via gloves contaminated following manipulation of venous cannulae and drip lines of the patient with Burkina Faso-acquired malaria and which had not been discarded before manipulating the intravenous lines of the other two patients. Nosocomial transmission of unusual and potentially life-threatening infections should be taken into consideration in those settings where compliance with universal precautions is not rigorous.
National Institute for Occupational Safety and Health 1999: Most Teen Worker Injuries in Restaurants Occur in Fast Food
- Disease Center
- Control
Center for Disease Control (1999). National Institute for Occupational Safety and Health 1999: Most Teen Worker Injuries
in Restaurants Occur in Fast Food. NIOSH Publications,
Updated 4-7-2000. www.cdc.gov/nisoh/teenfast.html.
Food and Drug Administration of the United States: Food Code. Definitions Applicability of Terms Defined Statement of Application and Listing of Terms
- Fda
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Defined Statement of Application and Listing of Terms.
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Oven Mitts Used in Commercial. Food Service: National Sanitation Foundation Protocol
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National Sanitation Foundation Protocol. Protocol P149
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Food and Drug Administration of the United States Food Code: Cleaning of Equipment and Utensils Equipment Food-contact Surfaces Non Food-contact Surfaces and Utensils
- Fda