Prevent Cross Contamination Research Articles

Assessing Consumer Food Safety Knowledge and Practice at Temporary Events

ObjectivesMeat and poultry products are implicated as the likely source in 29% of reported foodborne illnesses and 22% of foodborne illness-linked deaths. A subset of meat-related foodborne illnesses occur at temporary events (TEs) such as sporting events or large social gatherings. This is likely due to their lack of food safety infrastructure, trained food preparers, and conventional food preparation facilities. Previous studies suggest that most food preparers at pre-game tailgate events (66%) do not use thermometers when cooking. The literature has limited data that evaluates attitudes and behaviors of people who attend these types of events. The purpose of this study was to determine if an in-person, hands-on food safety intervention is an effective approach in changing sustained self-reported behaviors of consumers.Materials and MethodsTrained instructors provided information on handwashing, cleaning and sanitizing, thermometer use, and indicating meat doneness to customers (n = 107) of the Penn State University Meat Lab. Instructors used a semi-structured script and group-based learning to deliver consistent information while leaving room for more personalized dialogue and questions. Four educational stations were utilized to conduct hands-on demonstrations and empower participants while they applied newly acquired skills. Self-reported food safety behavior data was collected prior to providing food safety information and 1 and 4 mo following the intervention.Results50.8% of participants reported thermometer use when cooking meat prior to being presented with information for home thermometer use (n = 107). Of the participants that responded after 1 mo (n = 41), 77.4% reported using temperature to determine doneness for meat preparation. A paired t test on thermometer use frequency revealed a significant increase (p 0.05) between 1 and 4 mo post intervention (n = 32).Retention of knowledge was measured on a 1 (not knowledgeable) to 5 (very knowledgeable) Likert scale. A paired t test of participants from the pre and 1 mo post assessment showed knowledge significantly increased (p 0.05) between 1 and 4 mo for cross contamination and cleaning and sanitizing (n = 32).After 1 mo, 92.7% of participants reported changing food safety behaviors as a result of the intervention (n = 41). Improvements were reported in the following areas: cleaning and sanitizing (39.5% of participants), using a food thermometer (36.8%), handwashing (13.2%), cooking to the proper temperature (13.2%), preventing cross contamination (10.5%), other (10.5%), and unspecified (2.6%) (n = 41).ConclusionResults from this training indicate that hands-on stations centered around TE-specific risk factors can significantly increase knowledge and self-reported safe practices of TE participants and sustain them through 4 mo. As many food preparers at TEs have not received professional food safety training, education and skill-building that leads to proper food safety behaviors is crucial in reducing the amount of improper food safety behaviors at TEs. The practicality and effectiveness of this intervention makes it an ideal option for educating future TE-specific audiences.

Assessing Consumer Food Safety Knowledge and Practice at Temporary Events

ObjectivesMeat and poultry products are implicated as the likely source in 29% of reported foodborne illnesses and 22% of foodborne illness-linked deaths. A subset of meat-related foodborne illnesses occur at temporary events (TEs) such as sporting events or large social gatherings. This is likely due to their lack of food safety infrastructure, trained food preparers, and conventional food preparation facilities. Previous studies suggest that most food preparers at pre-game tailgate events (66%) do not use thermometers when cooking. The literature has limited data that evaluates attitudes and behaviors of people who attend these types of events. The purpose of this study was to determine if an in-person, hands-on food safety intervention is an effective approach in changing sustained self-reported behaviors of consumers.Materials and MethodsTrained instructors provided information on handwashing, cleaning and sanitizing, thermometer use, and indicating meat doneness to customers (n = 107) of the Penn State University Meat Lab. Instructors used a semi-structured script and group-based learning to deliver consistent information while leaving room for more personalized dialogue and questions. Four educational stations were utilized to conduct hands-on demonstrations and empower participants while they applied newly acquired skills. Self-reported food safety behavior data was collected prior to providing food safety information and 1 and 4 mo following the intervention.Results50.8% of participants reported thermometer use when cooking meat prior to being presented with information for home thermometer use (n = 107). Of the participants that responded after 1 mo (n = 41), 77.4% reported using temperature to determine doneness for meat preparation. A paired t test on thermometer use frequency revealed a significant increase (p < 0.05) in frequency pre and 1 mo post intervention (n = 41), and no significant change (p > 0.05) between 1 and 4 mo post intervention (n = 32).Retention of knowledge was measured on a 1 (not knowledgeable) to 5 (very knowledgeable) Likert scale. A paired t test of participants from the pre and 1 mo post assessment showed knowledge significantly increased (p < 0.05) for lessons addressing cross-contamination, cleaning and sanitizing, and handwashing (n = 41). A similar test showed sustained knowledge (p > 0.05) between 1 and 4 mo for cross contamination and cleaning and sanitizing (n = 32).After 1 mo, 92.7% of participants reported changing food safety behaviors as a result of the intervention (n = 41). Improvements were reported in the following areas: cleaning and sanitizing (39.5% of participants), using a food thermometer (36.8%), handwashing (13.2%), cooking to the proper temperature (13.2%), preventing cross contamination (10.5%), other (10.5%), and unspecified (2.6%) (n = 41).ConclusionResults from this training indicate that hands-on stations centered around TE-specific risk factors can significantly increase knowledge and self-reported safe practices of TE participants and sustain them through 4 mo. As many food preparers at TEs have not received professional food safety training, education and skill-building that leads to proper food safety behaviors is crucial in reducing the amount of improper food safety behaviors at TEs. The practicality and effectiveness of this intervention makes it an ideal option for educating future TE-specific audiences.

Operating Theatre Mannerisms &amp; Etiquette: Revisited!

Operating Theatre Mannerisms &amp; Etiquette: Revisited!

Modified Roller Tube Method for Precisely Localized and Repetitive Intermittent Imaging During Long-term Culture of Brain Slices in an Enclosed System

Cultured rodent brain slices are useful for studying the cellular and molecular behavior of neurons and glia in an environment that maintains many of their normal in vivo interactions. Slices obtained from a variety of transgenic mouse lines or use of viral vectors for expression of fluorescently tagged proteins or reporters in wild type brain slices allow for high-resolution imaging by fluorescence microscopy. Although several methods have been developed for imaging brain slices, combining slice culture with the ability to perform repetitive high-resolution imaging of specific cells in live slices over long time periods has posed problems. This is especially true when viral vectors are used for expression of exogenous proteins since this is best done in a closed system to protect users and prevent cross contamination. Simple modifications made to the roller tube brain slice culture method that allow for repetitive high-resolution imaging of slices over many weeks in an enclosed system are reported. Culturing slices on photoetched coverslips permits the use of fiducial marks to rapidly and precisely reposition the stage to image the identical field over time before and after different treatments. Examples are shown for the use of this method combined with specific neuronal staining and expression to observe changes in hippocampal slice architecture, viral-mediated neuronal expression of fluorescent proteins, and the development of cofilin pathology, which was previously observed in the hippocampus of Alzheimer's disease (AD) in response to slice treatment with oligomers of amyloid-β (Aβ) peptide.

Modified Roller Tube Method for Precisely Localized and Repetitive Intermittent Imaging During Long-term Culture of Brain Slices in an Enclosed System.

Cultured rodent brain slices are useful for studying the cellular and molecular behavior of neurons and glia in an environment that maintains many of their normal in vivo interactions. Slices obtained from a variety of transgenic mouse lines or use of viral vectors for expression of fluorescently tagged proteins or reporters in wild type brain slices allow for high-resolution imaging by fluorescence microscopy. Although several methods have been developed for imaging brain slices, combining slice culture with the ability to perform repetitive high-resolution imaging of specific cells in live slices over long time periods has posed problems. This is especially true when viral vectors are used for expression of exogenous proteins since this is best done in a closed system to protect users and prevent cross contamination. Simple modifications made to the roller tube brain slice culture method that allow for repetitive high-resolution imaging of slices over many weeks in an enclosed system are reported. Culturing slices on photoetched coverslips permits the use of fiducial marks to rapidly and precisely reposition the stage to image the identical field over time before and after different treatments. Examples are shown for the use of this method combined with specific neuronal staining and expression to observe changes in hippocampal slice architecture, viral-mediated neuronal expression of fluorescent proteins, and the development of cofilin pathology, which was previously observed in the hippocampus of Alzheimer's disease (AD) in response to slice treatment with oligomers of amyloid-β (Aβ) peptide.

Impact of unhygienic conditions during slaughtering and processing on spread of antibiotic resistant Escherichia coli from poultry

Antibiotic resistance in Escherichia coli is a global health concern. We studied all possible routes of cross contamination of broiler meat with resistant E. coli from broiler feces at poultry shops. Various sample categories namely poultry feces, meat (n=225 for each), slaughterer hands, consumer hands, slaughterer knife, canister, tap water, carcass, feed and drinking water (n=50 for each) were collected from local poultry processing market. Samples were screened for prevalence of E. coli, resistance of isolates against ten antibiotics and presence of tetracycline- resistance genes in the isolates. Fecal samples had greatest colony count (4.1×104 CFU/g) as compared to meat (1.9×104 CFU/g) samples. Samples of consumer hands (6%) and tap water (12%) had less prevalence percentages of E. coli as compared to slaughterer hands (92%) and drinking water of broiler (86%). Isolates of eight sample categories had high resistant rate (≥90%) against oxytetracycline. On average, about 94% of the isolates from various sample categories possessed multidrug-resistance (MDR). Tetracycline-resistance genes (tetA and tetB) were identified in all sample categories except isolates of consumer hands and tap water. The distribution of tetracycline-resistance genes was significantly greater in fecal isolates (42%) than meat isolates (25%). The study depicted the spread of resistant E. coli in broiler meat through all studied routes of contamination of slaughtering periphery. This problem can be mitigated by strict monitoring of antibiotics use at poultry farms, prevention of cross contamination by adopting hygienic slaughter and vigorously screening the market meat for resistant E. coli.

Dynamic changes in free-chlorine levels within a commercial post-harvest wash and prevention of cross-contamination between shredded lettuce batches

The dynamic changes in free-chlorine levels within a commercial shredded lettuce washing process and implications for preventing cross-contamination by human pathogens during processing has been determined. The commercial lettuce processing line incorporated a pre-wash in Wash Tank 1 followed by a biocidal wash in Wash Tank 2. Within the commercial wash process, the free-chlorine concentration fluctuated in a cyclic pattern (ranging from 4 to 27 ppm) in Wash Tank 1 but was depleted within Wash Tank 2 (low as 0.1 ppm). Despite the variation in free-chlorine levels the Oxidation Reduction Potential of the wash tanks remained stable and consequently there was no significant correlation to free-chlorine levels and ORP (r2 = 0.37). From analysis of the spent wash water it was found the Chemical Oxygen Demand (COD) was significantly higher in Wash Tank 1 (>5000 mg/l) compared to Wash Tank 2 (800–1001 mg/l). Significantly, both wash tanks operated below the chlorine demand that partly explained the inability to maintain constant free-chlorine levels. In laboratory studies, the spent wash water (containing disinfection byproducts) from the Wash Tanks supported inactivation of Salmonella (>3 log cfu reduction), Listeria monocytogenes (>4 log cfu reduction) and Escherichia coli O157:H7 (1–3 log cfu reduction). By adding chlorine beyond the chlorine breakpoint it was possible to achieve >4 log cfu reduction of the aforementioned pathogens, in addition to minimizing cross-contamination events between batches. The study has illustrated that commercial wash tanks for leafy greens operate below the chlorine breakpoint and hence maintaining specific free chlorine levels would be an unsuitable monitoring metric. Although disinfection byproducts contributed to antimicrobial capacity of the wash tank water it would be challenging to designate a specific limit of free-chlorine for purpose of process monitoring.

Scientific and practical approaches to minimization of risks of cross contamination in the conditions of combined production of parenteral medicines

The complexity of organizing the production of high-tech parenteral medicines, as well as the need to provide their competitiveness and price affordability require the introduction of the integrated management concept that takes into account the use tools of quality management, project management and risk management.Aim. To develop scientific and practical approaches to minimize the risks of cross contamination in the conditions of combined production of parenteral medicines in accordance with the ICH Q9 requirements.Materials and methods. The data of scientific literature, legal acts regulating the risk management issues in the conditions of combined production were studied; Ishikawa chart, control cards were used for identification and assessment of risk.Results. Using the control card construction the risks of cross contamination were assessed in the conditions of combined production of parenteral medicines on the example of the risk of air pollution, their causes in the critical stages were analyzed, the feasibility of the introduction of the system of the measures developed aimed at preventing and reducing the risk of cross contamination was substantiated.Conclusions. The introduction of the system of the measures developed to prevent cross contamination risks will promote the increase of the quality level for pharmaceutical products due to the minimization of contamination of the combined production of parenteral medicines at JSC “Farmak”.

Bacterial contamination of medical doctors’ white coats as contributing factor to hospital acquired infections

This study was carried out to determine the degree of contamination by bacterial agents on the white coats in hospital setting. Multistage method was used to select respondents across cadre, sex and department for the questionnaire. Cuffs, sleeve and mouths of pocket of doctors’ white coats were swabbed using wet sterile swab stick. The swabs were analyzed using standard procedure for bacterial contamination. The study revealed that 77.7% of the coats were contaminated with Staphylococcus aureus (45.1%), Staphylococcus epidermidis (26.2%), Klebsiella pneumoniae (22.6%), Pseudomonas aeruginosa (3.7%) and Enterococcus faecalis (2.4%). White coats of male resident doctors were more contaminated than that of the female resident doctors, while white coats of doctors from the Department of Surgery had the highest degree of contamination than other Departments. There was a significant difference between the age of white coats, usage, frequency of washing and number of white coats per doctor (P 0.05). Conclusively, doctors’ white coats were highly contaminated with pathogenic aerobic bacteria. Proper maintenance and handling practices of the white coats are precautions to be taken in order to minimize the degree of bacterial contamination and to prevent cross contamination of healthcare associated infection pathogens in hospital setting. Keywords : Medical doctors, White coats, Bacteria, Hospital, Infection, Healthcare.

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

&#x0D; 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 &amp; 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.&#x0D;

Bacterial adhesion capacity on food service contact surfaces

The aim of this study was to analyse the adhesion of E. coli, P. aeruginosa and S. aureus on food contact materials, such as polyethylene terephthalate, silicone, aluminium, Teflon and glass. Surface roughness, streaming potential and contact angle were measured. Bacterial properties by contact angle and specific charge density were characterised. The bacterial adhesion analysis using staining method and scanning electron microscopy showed the lowest adhesion on smooth aluminium and hydrophobic Teflon for most of the bacteria. However, our study indicates that hydrophobic bacteria with high specific charge density attach to those surfaces more intensively. In food services, safety could be increased by selecting material with low adhesion to prevent cross contamination.

Evaluation of one-way valves used in medical devices for prevention of cross-contamination

One-way valves used in day use devices (used on multiple patients throughout a day without reprocessing between patients) are intended to reduce the potential for cross-contamination between patients resulting from the backflow of patient fluids. One-way valves are typically designed to withstand high levels of back pressure before failure; however, they may not be explicitly designed as a means of infection control as used in medical device applications. Five different medical grade one-way valves were placed in low pressure configurations. After flushing in the intended direction of flow, bacteriophage, bacteria, or dye was placed patient side for 24 hours. The upstream device side of the valve was then evaluated for microbial growth or presence of visible dye. Leakage (ie, backflow) of the microorganisms occurred with a variety of one-way valve designs across a range of fluid properties tested. This study describes testing of the one-way valves (component-level testing) for the potential of cross-contamination. Although day use medical device systems may use numerous other factors to prevent patient cross-contamination, this work demonstrates that one-way valves themselves may not prevent leakage of contaminated fluid if the fluid is able to reach the upstream side of the one-way valve.

Food safety knowledge among food service staff in hospitals in Jordan

This study aimed to measure food safety knowledge among food service staff in hospitals in Jordan. A total of 532 food service personal (dietitians, cooks and food workers) from 37 hospitals (public, private, and university hospitals) were conveniently selected to participate in this cross sectional study. The participants completed a questionnaire composed of two parts (general characteristics and food safety knowledge). The overall food safety knowledge of food service staff is fair with a mean score of 56.3 out of 90 points (62.5%). Respondents had sufficient knowledge on “cross contamination prevention and sanitation” aspect, while they had very poor to good knowledge on “foodborne pathogens and related symptoms and illnesses”, “safe storage, thawing, cooking, holding and reheating of the foods”, “health problems that would affect food safety” and “personal hygiene” aspects. There were no significant associations between the total food safety knowledge score and age, educational level, marital status, income, experience, nature of work and attending course(s) on food safety. Respondents from public hospitals and who believed that HACCP is not important for food safety had significantly lower food safety knowledge score than those from private sector (OR: 3.3, CI: 1.76–6.01) and those who believed that HACCP is important (OR: 3, CI: 1.64–5.36), respectively. Food workers and respondents who have experience ≤48 months had significantly lower food safety knowledge score than dietitians (OR: 2.6, CI: 1.33–5.2) and those who have experience > 48 months (OR: 1.9, CI: 1.06–3.51), respectively. There is an urgent need for tailored food safety education and training programs that improve food safety knowledge of food service staff in hospitals in Jordan.

Experimental effect of ozone upon the microbial flora of commercially produced dairy fermented products

Ozone was used to control spoilage microorganisms during the manufacturing of dairy products. Ozone stream was applied onto the surface of freshly filled yoghurt cups just before storage for curd development in order to prevent cross contamination from spoilage airborne microorganisms. Accordingly, brine solution was bubbled with ozone for various periods of time and used for ripening of white (feta type) cheese. Both products were subjected to a continuous monitoring of microbial load and also tested for their sensorial properties. In ozonated yoghurt samples there was a reduction in mould counts of approximately 0.6Logcfu/g (25.1%) by the end of the monitoring period in relation to the control samples. In white cheese ripened with ozonated brine (1.3mg/L O3, NaCl 5%) it seems that ozone treatment during the two months of observation reduced some of the mould load but without offering any advantages over the use of traditional brine (NaCl 7%). However, some sensorial alterations were observed, probably due to the organic load in the brine which deactivates ozone in early stages of application. It is concluded that, if the factors of time and concentration of ozone are configured properly, ozonation could be a promising approach safeguarding the production of some dairy products.

A longitudinal evaluation of food safety knowledge and attitudes among Ontario high school students following a food handler training program

Youth are a unique audience for food safety education, in part due to low food safety knowledge. Although the effectiveness of such education has been explored for primary school and college students, no studies have assessed effectiveness among high school students specifically. We conducted a longitudinal intervention study in Ontario, Canada, between February and May 2015, to measure the baseline food safety knowledge and attitudes of high school students (n = 119; from 8 classes in 4 high schools), and determine whether these factors improved following in-class delivery of a provincial standardized food handler training program. Linear mixed effects regression models were used to model within-student changes in knowledge scores and attitudes over time (i.e., circa 2 and 12 weeks post-intervention), and to investigate associations with student characteristics. At baseline, knowledge and attitudes were poor. Following training, overall knowledge was significantly greater than at baseline, although at three months post-intervention only knowledge of safe times and temperatures for cooking and storing food remained significantly higher than baseline. Following training, students were significantly less interested in learning about how to avoid foodborne disease. Other attitudes, as well as knowledge of cross-contamination prevention and disinfection procedures, remained unchanged. These findings suggest that delivering existing food handler training programs within high schools may be a feasible mechanism for food safety educators to improve students' food safety knowledge, both overall and specific to safe times and temperatures, albeit potentially for short timeframes. Whether knowledge continues to decline beyond three months after training bears further investigation. As well, future research to investigate how students' actual food safety practices may change following such training, and whether improvements in knowledge translate into reduced foodborne disease risk, is warranted.

Content Validation and Semantic Evaluation of a Check-List Elaborated for the Prevention of Gluten Cross-Contamination in Food Services.

Conditions associated to the consumption of gluten have emerged as a major health care concern and the treatment consists on a lifelong gluten-free diet. Providing safe food for these individuals includes adapting to safety procedures within the food chain and preventing gluten cross-contamination in gluten-free food. However, a gluten cross-contamination prevention protocol or check-list has not yet been validated. Therefore, the aim of this study was to perform the content validation and semantic evaluation of a check-list elaborated for the prevention of gluten cross-contamination in food services. The preliminary version of the check-list was elaborated based on the Brazilian resolution for food safety Collegiate Board Resolution 216 (RDC 216) and Collegiate Board Resolution 275 (RDC 275), the standard 22000 from the International Organization for Standardization (ISO 22000) and the Canadian Celiac Association Gluten-Free Certification Program documents. Seven experts with experience in the area participated in the check-list validation and semantic evaluation. The criteria used for the approval of the items, as to their importance for the prevention of gluten cross-contamination and clarity of the wording, was the achievement of a minimal of 80% of agreement between the experts (W-values ≥ 0.8). Moreover, items should have a mean ≥4 in the evaluation of importance (Likert scale from 1 to 5) and clarity (Likert scale from 0 to 5) in order to be maintained in the instrument. The final version of the check-list was composed of 84 items, divided into 12 sections. After being redesigned and re-evaluated, the items were considered important and comprehensive by the experts (both with W-values ≥ 0.89). The check-list developed was validated with respect to content and approved in the semantic evaluation.

広島県内の食鳥処理場におけるカンピロバクター交差汚染防止の検討

広島県内の食鳥処理場で処理された鶏の盲腸内容物のカンピロバクター分離率は12％（13/108）で，分離株はすべてCampylobacter jejuniと同定された．盲腸内容物からカンピロバクターが分離された鶏（以下，保菌鶏群）の処理時のと体やチラー水から本菌が分離された．盲腸内容物から本菌が分離されなかった鶏（以下，非保菌鶏群）の処理時のと体，チラー水のいずれからも本菌は分離されなかった．保菌鶏群の処理後に非保菌鶏群のと体から本菌が分離されたことから，交差汚染を受けている可能性が示唆された．また，冷却後のと体からも本菌が分離されたことから，現在の衛生管理方法ではカンピロバクター汚染は排除できないと考えられた．一方で，保菌鶏群の前に非保菌鶏群を処理すること（区分処理）で交差汚染を防ぐことができた．したがって，区分処理はカンピロバクターの交差汚染防止に効果的であることが示唆された．

Evaluation of Surface Microhardness Following Chemical and Microwave Disinfection of Commercially Available Acrylic Resin Denture Teeth.

Denture disinfection is an indispensable procedure for preventing cross contamination and the maintenance of a healthy oral mucosa in patients rehabilitated with removable dental prosthesis. Nevertheless, they are known to cause changes in the physical and mechanical properties of denture base resins and acrylic resin denture teeth following immersion of a denture in a suitable chemical disinfectant solution or by undergoing microwave irradiation. One such mechanical property indicator for artificial tooth materials is hardness. To assess the surface hardness of acrylic resin teeth of three different commercial brands (Ivoclar, Newace, Acryrock) following chemical (2% glutaraldehyde, 1% sodium hypochlorite) and microwave disinfections. Ten specimens of each of the three commercial brands were made for control and each simulated disinfection type and stored in distilled water at room temperature for 24 hours. After water storage, specimens were immersed in 2% glutaraldehyde and 1% sodium hypochlorite (one and three cycles) at room temperature for 10 minutes. Irradiation with microwave (one and three cycles) was done in domestic microwave for three minutes with the specimens immersed in 150 ml of distilled water. The specimens were stored in distilled water at room temperature for seven days after each disinfection cycle. Vickers hardness measurements were made using a hardness indenter under a load of 50 g force for 10 seconds. Data was subjected to repeated measure two-way ANOVA test and Tukey's test. There were statistically significant differences for the variables disinfection, tooth, and cycle (p<0.05 for teeth & disinfectant interaction, p<0.05 cycle and disinfectant interaction). The mean surface hardness following one microwave disinfection cycle was lower than control, glutaraldehyde and sodium hypochlorite. Comparison among cycles revealed that microhardness was significantly decreased for three cycles of microwave disinfection. It was concluded that there was no significant difference in microhardness when the teeth were subjected to chemical disinfection but three cycles of microwave disinfection produced decrease in the microhardness of different types of artificial teeth.

Evaluation of Efficiency of Different Decontamination Methods of Dental Burs: An In vivo Study.

Introduction:Infection control is very important in dentistry. Both dentist and patients are at risk of communicating diseases during treatment procedures. Dental burs have been identified as a source of cross-contamination between patient and dental personnel.Aim:The present study was done to quantitatively and qualitatively assess the pathogenic contamination of dental burs used for tooth preparation and to determine the effective method of sterilization(autoclave, glass bead sterilizer, hot air oven and surgical spirit immersion) of burs used for crown preparation.Methodology:Dental burs were assessed before and after tooth preparation, also after sterilization burs were evaluated.Conclusion:Findings of our study revealed that among the experimental groups used in the present study, Autoclave and Hot air oven was found to be the relatively best method to sterilize burs. Proper cleaning and sterilization of burs should be strictly employed to prevent cross contamination in clinical practice.

Preincubation of Escherichia coli ATCC 25922 with NaCl Increases Its Attachment to Lettuce Surfaces Compared with Other Chemicals.

The inhibition of microbial attachment to food is important for the prevention of cross-contamination during food processing. The effect of several chemicals that were added in an Escherichia coli growth medium on the attachment of the bacterium to lettuce was investigated. E. coli ATCC 25922, which is reportedly a useful surrogate for E. coli O157:H7 in surface attachment studies, was preincubated in a nutrient broth (NB) containing sodium chloride, potassium chloride, sodium deoxycholate, sodium linear alkylbenzene sulfonate, or sorbic acid. The bacterial cells were placed in contact with cut lettuce in a saline solution at 5℃ for 24 hours. Only the addition of NaCl in the NB influenced the attachment of E. coli, Salmonella enterica subsp. Enteritidis, and Klebsiella pneumoniae to the lettuce. The attachment of E. coli showed the largest significant increase at 2% NaCl. Changes in the attachment levels were not due to surface hydrohobicity or the motility of E. coli cells. Similar results were observed for S. enterica although the variation in the degree of attachment of the latter was quite small. These results suggested that the attachment of E. coli O157:H7 to food surfaces is influenced by the bacterial growth conditions prior to food exposure and prior to the development of the biofilm; furthermore, the environmental NaCl concentration should be controlled during food processing to prevent the cross-contamination of foods with E. coli.