BCIT Environmental Public Health Journal
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DPD-based colorimetric quantification of free available chlorine (FAC) in floatation tank conditions
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Background: Floatation tanks are quickly gaining traction as a form of relaxation, with numerous spas emerging in the Lower Mainland and beyond. The tanks are filled with a solution of magnesium sulphate, recycled between client uses. Thus, there exists a potential for microbiological contamination and subsequently, disease transmission. Health inspectors in BC may be involved the approval and inspection process for floatation tank spas; therefore, it is important to ensure that floatation tank environments are not a vehicle for disease. As a preventative measure, guidelines are in place for the halogenation of tank water at a level of 3-5 ppm free available chlorine (FAC). However, there is no standard method for the accurate and reliable quantification of FAC in high salinity environments. This study characterized the effect of high salinity on FAC readings from the HACH Pocket Colorimeter™, and derived a conversion factor to obtain an accurate reading for inspectors in the field. Methods: Floatation tank environments were simulated using USP-grade Epsom salts, Clorox™ bleach, and a hot water bath set at approximately 34°C (93°F). Assuming an initial concentration of 5.25% sodium hypochlorite, the bleach was serially diluted to obtain concentrations from 1-8 ppm. The final dilution step involved the addition of either 34°C water or an Epsom salt solution (MgSO4) at a specific density of 1.220 to create two solutions with identical amounts of bleach - one with and one without salt. The solutions were tested for chlorine two minutes later through the addition of DPD - a colorimetric dye that results with FAC - and measuring the colour intensity using the Pocket Colorimeter II. A percentage recovery was derived using the ratio between measured FAC with and without salt, Results: There was a statistically significant difference (p=0.05) between measured chlorine levels with and without salt as determined by a paired t-test. Further analysis via ANOVA and a post-hoc multiple comparison test (Scheffe's) indicated a dose-response relationship - increasing the amount of hypochlorite in an Epsom solution results in a statistically significant increase in measured FAC between the following groups: 1-2 ppm, 3-5 ppm, and 6-8 ppm of added hypochlorite. Linear regression revealed a strong correlation (0.97) between measured chlorine with and without salt. Conclusions: The HACH Pocket Colorimeter II™ can be used to estimate the amount of FAC in a floatation tank solution using a conversion factor of 0.79; to obtain an accurate measurement, divide the FAC reading in salt by 0.79
 
Association between knowledge of the pneumococcal vaccine, vaccination status and recommendations for vaccination
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BACKGROUND Pneumococcal disease caused by Streptococcus pneumoniae has a high morbidity rate in elderly individuals aged 65 or older. Previous studies have demonstrated that low vaccination rates with the 23-valent pneumococcal polysaccharide vaccine (pneumovax) are due to a lack of awareness and knowledge about the vaccine in the general population. This study measured the association between the public’s knowledge of the pneumococcal vaccine, vaccination status, the type and number of health care facility visits per participant in the past year and number of advertisements seen for the vaccine. METHODS This study used a survey to test the knowledge of its participants on the pneumococcal vaccine and associated the results with nominal data such as vaccination status and recommendation for vaccination by their primary health care providers. The survey tested the participants using 15 true or false questions that assessed their knowledge on the pneumococcal vaccine and pneumococcal disease. RESULTS No association was found between the knowledge individuals have on the pneumococcal vaccine and whether their health care provider recommended the vaccine (p=0.467). However, a statistical difference in knowledge between individuals who are vaccinated and individuals who are not vaccinated was found (p=0.039 (CHI), p=0.011 (ANOVA)). There was also a positive association found between vaccination status and primary health care provider recommendation for the pneumococcal vaccine (p=0.001). No association was found between vaccination status and number of visits to a primary health care provider in the past year (p=0.149). Using an ANOVA analysis, it was found that there was a difference in number of advertising types seen for each vaccination status group (p=0.011). CONCLUSION Based on the results, it can be concluded that individuals who are vaccinated have more knowledge on the pneumococcal vaccine, but their knowledge is not affected by a recommendation to receive the vaccine from their primary health care provider. This suggests that health care providers are not providing sufficient information about the vaccine to their patients when they recommend it. Despite this knowledge gap, the association between vaccination status and primary health care provider recommendation for the vaccine indicates that individuals are more likely to get vaccinated when their primary health care provider recommends it. However, more visits to the provider annually did not influence the vaccination status of the patient. In addition, results from the ANOVA analysis suggest that participants who saw more vaccine advertisements were more likely to be vaccinated.
 
Evaluation of public health interventions in shellfish tag compliance rates
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Background: The recent Vibrio parahaemolyticus outbreak in the summer of 2015 highlighted that shellfish tags are one of the key pieces of information used to trace back and determine the source of a foodborne outbreak or illness associated with raw or uncooked shellfish. According to the Canadian Food Inspection Agency, all shellfish tags must meet the requirements stated in the Section 7.3 of the Canadian Shellfish Sanitation Program (CSSP). Non-compliant tags may hinder national and regional regulatory agencies from identifying problems in harvest locations and at the processors, and further impede provincial control measures. As a result of the national outbreak, the BC Center for Disease Control (BCCDC), Ministry of Agriculture and the Canadian Food Inspection Agency (CFIA), as well as health authorities and Environmental Health Officers (EHO) have been involved in a variety of actions and interventions to improve compliance. These include efforts to promote education and to improve control and surveillance of V. parahaemolyticus and other shellfish associated illnesses. This study examined the effectiveness of health agencies’ interventions to improve shellfish tag compliance rates to Section 7.3 of the CSSP by comparing the numbers of shellfish tags in compliance before and after the interventions that were implemented in 2016. Methods: 120 randomly selected shellfish tags were grouped into “Before” and “After” interventions. By assessing the date of processing, 60 tags collected before September 2016 were placed into the “Before” group. Another 60 tags collected after September 2016 were placed into the “After” group. Within each group, shellfish tags were individually analyzed to determine whether the tag met or exceeded the required quality, information, and type and quantity criteria. Shellfish tags were considered “Compliant” if they completely fulfill 10 components embodied in the criteria, whereas shellfish tags that failed to meet all the components were labeled “Non-compliant”. Results: Based on the statistical analysis conducted on the data, there was a greater proportion of compliant shellfish tags post-intervention compared to pre-intervention. The Pearson’s Chi-square test confirmed that there was a statically significant association (p-value = 0.000) between the numbers of shellfish tags in compliance and the interventions that were implemented after the outbreak. Conclusion: The results have demonstrated that the interventions implemented by numerous regulatory authorities resulted in greater compliance to Section 7.3 of the CSSP. Public health regulators including the Ministry of Agriculture and the CFIA, as well as BCCDC and EHOs should continuously be involved in a variety of actions, such as promoting education at the processor and retail level and also implementing interventions to improve compliance. By doing so, successful interventions and increased compliance rates will lead to rapid identification of shellfish-related illnesses or outbreaks and facilitate control measures that can expeditiously remediate public health issues.
 
Determining the accuracy of colorimetric pH testing compared to potentiometric methods
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Background: Bacterial growth in foods can be prevented by applying various controls to the food product, including adjusting the acidity of the food. Research has indicated that a pH level of 4.6 or lower will be effective to prevent most bacterial growth. In order to verify this level has been achieved pH test strips (colorimetric) or a digital calibrated pH meter (potentiometric) can be used. This study attempted to quantify the degree of accuracy that pH test strips have compared to the calibrated pH meter. Method: MColorpHastTM pH indicator strips with a pH range of 0-14 were tested against a calibrated Extech pH100 meter. In this study 40 samples of rice were acidified to varying levels. Each sample was measured with both colorimetric and potentiometric method. Results were compared to determine the level of accuracy of the pH test strips. As well, test strips were used to measure pH in a variety of different coloured preserves. Results: A two-tailed test showed that there was a statistically significant difference between the readings from the pH test strips and the digital pH meter (P=0.0003). Conclusion: Based on the results, it can be concluded that both methods of measurement are not equally accurate. A calibrated pH meter will give more accurate readings of pH levels and should be used in most cases to confirm food safety with a high degree of confidence. In testing dark coloured jellies and preserves, pH test strips should not be relied on as they will be stained by the food, making the colorimetric reading difficult to determine accurately.
 
Environmental health officers and climate change adaptation in British Columbia
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Background: The average annual temperatures in British Columbia have been steadily increasing in recent history and are expected to continue to rise. Climate change impacts have a significant effect on public health, and adaptation to these changes is necessary. Environmental health officers (EHOs) are in a position to deliver climate change adaptation programs in public health. The purpose of this study was to assess EHO perception of climate change adaption and identify knowledge or policy gaps. Methods: A self-administered online survey created used Google Forms was distributed through e-mail and social media to EHOs in BC. The survey asked for demographics information, beliefs about climate change, adaption, and public health. Chi-square tests and descriptive statistics were used to analyze results. Results: There was a significant association found between working in a mixed urban and rural environment and the incorporation of climate change adaptation into practice and the belief that climate change has impacted public health in BC. No association was found between years of experience and incorporation of adaptation. Conclusion: While EHOs generally recognize the public health impacts of climate change, there are many barriers preventing EHO involvement in climate change adaptation.
 
Evaluating the cleaning procedures of meat slicers at retail delis in Metro Vancouver
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Background: Ready-to-eat deli meats are widely consumed by the public; however they are also a high risk food for carrying Listeria monocytogenes. Listeriosis, an infection that can result from consumption of Listeria monocytogenes contaminated food, is the leading cause of deaths related to foodborne illness in Canada. Due to structural constraints and inadequate cleaning, mechanical slicers used to process deli meats have been implicated as a major source of Listeria monocytogenes contamination of deli meats. Several governing bodies, including local health authorities have published recommendations on the proper method of cleaning and sanitizing meat slicers to prevent the risk of contamination of deli meats. This study evaluated the compliancy of retail delis in Metro Vancouver to these recommendations and also assessed their knowledge of the risk associated with deli meats. Methods: An in-person, self-administered paper survey was conducted at several retail delis and supermarkets. The survey questions determined the cleaning and sanitation procedures of meat slicers at the establishments and also assed knowledge of the risk associated with deli meats. Both nominal and numerical data was collected and analyzed using a Chi-squre test and a t-test. Results: Based on the data collected, a statistically significant difference was identified between the cleaning procedures practiced by the establishments and those recommended to prevent pathogen transmission through meat slicers. The chi-square test revealed that there is a statistically significant association between the size of the establishment and the adequacy of cleaning procedures, with small-scale delis being less likely to comply with the cleaning practices that are recommended by governing bodies. Conclusion: Cleaning procedures practiced at retail delis and supermarkets are not consistent with those recommended by regulatory agencies to prevent the transmission of pathogens such as Listeria monocytogenes from meat slicers to deli meats. Smaller retail delis are less likely to follow proper cleaning methods than larger supermarket delis. Educational intervention by health authorities may be needed to ensure that food establishments are informed of proper and timely cleaning procedures.
 
Heterotrophic bacteria in botte refill stations
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Background: Heterotrophic bacteria are commonly found in water supplies where there is inadequate or non-existent disinfection. Water coolers are known to have high HPC levels due to the filtered, non-chlorinated water provided. Water bottle refill stations utilize a carbon filter which can act as a food source for HPC. This study measured HPC levels in water samples from bottle refill stations to determine whether there is a difference compared to tap water at BCIT. Method: Standard Method 9060 A was used to collect water from bottle refill stations to compare to non-filtered tap water. Samples were plated using R2A Agar and incubated for 7 days before enumerating HPC from water samples. Samples were collected from specific drinking water fountains that contained Carbon Filters and compared to the nearest tap water source. Results: Mean HPC levels in bottle refill stations were found at 95 cfu/mL while mean HPC levels in tap water were 55 cfu/mL. A two-sample T-test confirmed that the mean HPC levels of bottle refill stations and tap water are statistically significantly different (P= 0.000124). Although the findings were statistically significant, the study’s power was low at 11%. Conclusion: Based on the results, drinking water obtained from bottle-refill stations at BCIT contained on an average higher level of HPC compared to tap water. Overall, HPC levels were below recommended levels in drinking water and not considered to have any harmful effects. To continue the safe use of bottle refill stations, facilities should develop and follow written procedures to maintain stations and ensure regular changing of filters.
 
Knowledge comparison between group childcare centres and family childcares on sanitation of toys
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Background: Childcare facilities (CCFs) are known to have a high potential risk of exposure and transmission of infectious diseases through contact surfaces, such as toys. Research to date suggests that toys are a potential source of cross-infections in CCFs, especially when childcare providers do not practice proper hygiene. Currently, there is a lack of knowledge on the differences in sanitation methods of toys between group and family CCFs. This study compared knowledge of group and family CCFs regarding how to sanitize toys. Methods: Self-administered surveys were distributed to group and family CCFs in Surrey, BC via e-mail. The survey was used to assess the knowledge of childcare providers on sanitation of toys. The survey was evaluated using a scoring system. In addition, each participant answered descriptive questions, such as the existence of sanitation plans and toy cleaning and sanitizing schedules. Results: Group and family CCFs showed no statistically significant differences in knowledge levels on sanitation of toys. The mean score of the knowledge level of group and family CCFs was 65% and 55% respectively. Conclusion: Childcare providers in CCFs play a key role in properly sanitizing toys and preventing transmission of infectious diseases between children. Recognizing knowledge gaps in sanitation can lead to policy development as well as improved educational programs.
 
Assessing the risk of lead exposure to children from drinking water in Metro Vancouver child care facilities
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Background: Environmental lead exposure has been a concern since the early 1970’s. With the reduction of airborne lead for inhalation, ingestion from food and water has become the major route of exposure leading to elevated blood lead levels. Previous research and the recent lead contamination of drinking water in Flint, Michigan demonstrate the vulnerability of young children and potential for exposure through drinking water. The purpose of this study was to assess and characterize the risk of lead contamination of drinking water for Metro Vancouver-area early childhood care facilities, and the effect of flushing fixtures as a control measure. Method: 91 drinking water samples were collected from various fixtures at 16 child care facilities at progressive time points to observe the effects of flushing and re-stagnation on total dissolved lead content. Analysis was performed using Varian AAS-240 coupled with GTA-120 graphite furnace atomic absorption spectroscopy. Results were analysed statistically using Excel 2010 and SAS/STAT® 14.2 software with SAS Studio 3.6 interface. Results: The mean (SD, min-max) lead concentrations of the water samples were 0.69 (2.32, 0.1-11.27) μg/L at zero minutes of flushing, 0.21 (0.44, 0.1-2.19) μg/L after one minute of flushing, 0.15 (0.17, 0.1- 0.87) μg/L after five minutes of flushing, 0.18 (0.17, 0.1 -0.64) μg/L after re-stagnation, and 0.31 (1.20, 0.1-11.27) μg/L overall. One outlier sample had a lead concentration of 11.27 μg/L, which exceeded Health Canada’s maximum allowable concentration of 10 μg/L. The decrease in mean lead concentration between zero minutes and one minute of flushing was statistically significant (p=0.0020). Conclusions: The results indicate that lead contamination of drinking water in child care facilities is present but below regulatory action levels under normal circumstances. The flushing of fixtures for at least one minute was shown to be effective in lowering lead concentrations further. Efforts should be taken to identify facilities at higher risk of lead contamination and to educate operators of flushing as an effective control measure.
 
Efficacy of chlorine sanitizer spray bottles exposed to various temperatures and ambient light
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Background: Gastroenteritis is largely under reported across Canada. It is estimated that one reported case represents on average 313 cases. In addition, improper cleaning is one of the top ten reported causes of food borne illness. Sanitization is important to reduce the number of pathogenic microorganisms present on food contact surfaces to a safe level. Correct concentrations of sodium hypochlorite are to be prepared and used within the range of 100ppm – 200ppm on food contact surfaces. The purpose of this study was to evaluate the rate of degradation of sodium hypochlorite in spray bottles to assess if these solutions need to be prepared fresh daily to achieve efficacy. Two variables seen within a food service establishment were chosen to evaluate the rate of degradation, temperature and ambient light. Method: Room temperature (20˚C), 35˚C and ambient light exposure were tested to evaluate their effect on the degradation of free chlorine in spray bottles over time in days. The experiment was preformed by setting up 3 individual spray bottles at 20˚C with no light, 20˚C with ambient light and 35˚C with no light. The sodium hypochlorite was then sampled and recorded periodically three times a week over a 15-day period to determine the stability of the chorine solutions prepared at around 200ppm. Results: In the order of spray bottles tested, 20˚C no light, 20˚C ambient light and 35˚C no light, a correlation coefficient of -0.3027, -0.8235 and -0.8169 were recorded. In addition, the following test spray bottles held a r-squared value of 0.0916, 0.6781 and 0.6674. A p-value of 0.5094, 0.0249 and 0.0249 were also assessed, with a corresponding power of 8.99%, 73.74% and 71.75%. Conclusions: By calculating the linear regression formula, it was concluded that chlorine solution in spray bottles do not need to be prepared fresh daily. For 200ppm 20˚C no light, 200ppm 20˚C ambient light and 200ppm 35˚C no light, at days 128, 67 and 45, the estimated concentration of sodium hypochlorite will be at the minimum requirement of 100ppm respectively.