Background and Purpose: Adverse effects of lead and mercury on human health due to environmental and occupational exposures require a public health attention. These metals can cause severe harm to vulnerable populations such as children and pregnant women. The probability of chronic and harmful exposure is higher in occupational settings. Monitoring the levels of these two metals in blood is an important tool to identify and quantify exposure to these metals in the environment. Monitoring data provides vital information required for management of health risk posed by these metals. The purpose of this study was to perform a comparative analysis of blood lead levels and blood mercury levels within the province of British Columbia on the health services data obtained from BC Centre of Disease Control. The primary objective was to compare the levels of lead and mercury in blood among different health authorities of British Columbia. The secondary objective was to compare the levels of lead and mercury among different age groups and gender.
Methods: The blood lead and mercury concentrations used for the analysis were provided by Environmental Health Services at the British Columbia Centre for Disease Control (BCCDC). The data comprised of blood analyses that were ordered by physicians during the period of 2009-2010 for reasons not disclosed. Access to this data was provided by Dr. Reza Afshari with the permission of Dr. Tom Kosastsky for the completion of this project only. Statistical analysis of data was performed using Microsoft Excel 2013 and SAS University Edition Analytic Software. Various descriptive and inferential statistical tests were performed on the data to determine the differences of blood mercury and lead levels among different genders, Health Authorities and age groups.
Results: The levels of blood mercury and lead concentrations were not significantly different in males and females in province (p-value 0.5543 for mercury; p-value 0.5336 lead). However, it was found that blood levels of lead were higher in Interior Health and “Unknown” category (p<0.02), while blood mercury levels were significantly higher in coastal health authorities (highest in Vancouver Coastal Health Authority, followed by Fraser Health Authority and Vancouver Island Health Authority) (p<0.001). For both toxic metals, levels were highest in age group of 50 and above. (p<0.0001 for mercury, p<0.02 for lead).
Conclusion: The statistical analysis of lead and mercury data was useful in characterizing the exposure among Health Authorities, age and sex of the people tested in province of British Columbia. Analysis of mercury data has generated clear patterns inferring association between coastal Health Authorities and elevated mercury levels. Vancouver Coastal Health had highest median mercury levels 4.02 μg/L higher than other health authorities (p<0.0001). Analysis of lead data established a pattern among physicians suggesting that they are more likely to order a test if the patient is under 18 years of age. Median levels were found to be highest in Interior Health Authority and “Unknown”, Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2016., Peer reviewed, Lead, Mercury, Pregnancy, Children, British Columbia, Blood lead levels, Blood mercury levels, Vancouver Coastal Health, Fraser Health, Interior Health, Northern Health, Vancouver Island Health Authority, Occupational exposure
Background: Hand sanitizers are commonly used as an alternative to washing hands with warm water and soap. There are a variety of different hand sanitizers including gel and foam and they are known to kill several bacteria. Many factors play a role in the effectiveness of hand sanitizers such as the alcohol concentration and the techniques used to apply hand sanitizers. Alcohol based hand sanitizers must have an alcohol concentration of 60 - 70% to be effective. There is currently no legislation regulating hand sanitizers and there is a lack of research focusing on differences between foam and gel hand sanitizers. This research study investigates effectiveness of gel compared to foam hand sanitizers by evaluating the prevalence of Escherichia coli (E.coli) on pigskins.
Methods: To compare the hand sanitizers, microbiological sampling was completed. E.coli was introduced onto 65 pigskins. Five pigskins were used as a baseline to determine the average amount of Colony Forming Units (CFUs) of E.coli present prior to the application of hand sanitizers. One set of the 30 pigskins was applied with gel hand sanitizer, whereas the other 30 was applied with foam hand sanitizer. The pigskins were swabbed with QuickSnap swabs and plated onto 3M Petrifilms. The 65 petrifilms were incubated at 35oC for 48 hours. After incubation, the CFUs of E.coli present on the petrifilm were enumerated. The difference in CFUs was calculated to determine the reduction in E.coli and the overall effectiveness of hand sanitizers.
Results: The data was analyzed by using the statistical software, NCSS. Statistical analysis showed that the findings were statistically significant and the null hypothesis (Ho: no difference in CFUs of E.coli between foam versus gel alcohol-based hand sanitizers) was rejected with a power of 0.9997 at p-value of 0.00000. This indicates that there is a difference in the ability to reduce E.coli between gel and foam hand sanitizers and gel sanitizers appeared to be more effective.
Conclusion: These results indicate that there was a difference in the effectiveness between foam and gel hand sanitizers in reducing E.coli that was inoculated onto pigskins. However, consumers should be aware that hand sanitizers do not completely eliminate all pathogens. Though gel hand sanitizers are more effective, they should only be used when there are no other methods of keeping hands clean., Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2016., Peer reviewed, E.coli, Escherichia coli, Foam, Gel, Hand Sanitizer, Pigskin, Public health
Background: Water quality in live retail shellfish holding tanks are vital in increasing shellfish quality and reducing risk of shellfish-associated outbreaks. Poor holding tank water conditions may not only cause mortality of shellfish, but also allow for harmful pathogens to contaminate the shellfish, proliferate in the holding tanks, and ultimately potentially affect consumer health. Shellfish are processed and handled at a variety of levels at the retail stage. Therefore, the purpose of this research project is to compare water quality in live retail shellfish holding systems between processing plants and retail food markets. Differences may indicate a need for attention at a particular level in order to effectively and efficiently reduce mortality and disease among shellfish, and thus potentially humans as well. Methods: 30 water samples were taken from the two types of locations with the help of the Department of Fisheries and Oceans (DFO), Ministry of Agriculture, and the BCCDC. These samples were tested for parameters including temperature, pH, nitrites, turbidity, and dissolved oxygen using a LaMotte Fresh Water Aquaculture Kit and a HACH 2100P turbidimeter. A two-tailed t-test was used to compare the means of each of the parameters among the two types of locations with live shellfish holding tanks. Results: The mean values for all parameters in both retail and processing met the requirements set by the BCCDC. However, temperature and dissolved oxygen showed statistically significant differences between retail markets and processing facilities. Nitrites, pH, and turbidity showed no statistically significant differences between the two types of locations. Conclusion: Differences in dissolved oxygen may have been due to salt levels, failing recirculation systems, or high levels of organic matter from sanitation issues. Differences in temperature may have been due to differences in holding tank size, or inconsistencies from using two different thermal measuring devices. High levels of nitrites were a concern as well due to overcrowding of holding tanks. More attention may be needed for these issues, especially during certain seasons such as Chinese New Years, in order to lower the risk to public health., Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2016., Peer reviewed, Shellfish, Holding tanks, Water quality, Processing facility, Retail food market, Food safety, Public health
Background and Purpose: Personal service establishments are abundant such as piercing shops, tattoo parlours, spas and now float spas. Sensory deprivation tanks were popular in the 1980s and have come back as a new way to relax, reduce pain and relieve stress and to provide a complete deprivation of the senses. The sanitation of these tanks have caused concern in the public health field as bacteria and parasites can easily live and proliferate in the tank water. Environmental Health Officers (EHOs) have to keep up to date with new or returning technology in order to provide information to the public and to ensure their safety. This research project investigated EHOs with differing years of employment in the field, geographic working location and age and their knowledge of sensory deprivation tanks.
Methods: A survey created in Google Forms and Survey Monkey was disseminated through e-mail who then forwarded an e-mail to all EHOs in BC. The survey asked demographic questions, health and safety, sanitation and disinfection and general knowledge of floatation tanks. A t-test and ANOVA was used to analyze the data.
Results: Three comparisons were tested: first was the number of years an EHO has worked in the field and their test score; second was their age and test score; and last was their geographic location and test score. The null hypotheses were not rejected as the p-value was found to be greater than 0.05 for all of the variables analyzed.
Discussion: Overall, there was weak knowledge in EHOs and due to the small sample size there was weak statistical significance between the associations found regarding the number of years an EHO has worked in the field, their age and geographic location where they work compared to their test scores.
Conclusion: More information needs to be provided to all EHOs to keep them updated on new personal service establishments., Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2016., Peer reviewed, Floatation tanks, Sensory deprivation tanks, Environmental health officer, Knowledge, BC, Public health, Personal service establishments, PSE, Float tank, REST tank, Isolation tank
Background and Purpose: Hand washing is one of the most important critical control points in public
premises in preventing the spread of bacteria and viruses. There is vast research on the effectiveness of
alcohol-based hand sanitizers in killing germs. However, the efficacy of alcohol-free hand sanitizers lacks
real-world evidence. With little to no guidelines in which one type of hand sanitizers may be more
appropriate depending on the types of public premise such as food establishments, hospitals, work place, or
schools, Environmental Health Officers(EHOs)/ Public Health Inspectors(PHIs) will need to educate the
public and operators on the effectiveness of these hand sanitizers and their advantages and disadvantages.
The purpose of the study was to compare the effectiveness of alcohol-based hand sanitizers and alcoholfree
hand sanitizers by conducting statistical analyses of the reduction in mean E.coli counts.
Methods: 60 pigskins were prepared (30 for alcohol-based hand sanitizers, 30 for alcohol-free hand
sanitizers), which were inoculated with E. coli, then applied either alcohol-based hand sanitizers or alcoholfree
hand sanitizers. After 48 hours of incubation for E.coli growth, E.coli was counted. The difference in
mean E.coli counts before applying hand sanitizers and after hand sanitizers was calculated, then compared
between the two hand sanitizers.
The mean E.coli reduction count (CFU) from alcohol-based hand sanitizers (30 samples) was 10.200; the
median was 11; the standard deviation was 1.7889; the range was 5.0000.
The mean E.coli reduction count (CFU) from alcohol-free hand sanitizers (30 samples) was 10.233; the
median was 10.5; the standard deviation was 0.8976; the range was 3.0000.
The statistical t-test resulted in p-value of 0.1034.
Conclusion: There was no significant difference between the two types of hand sanitizers. Both the
alcohol-based hand sanitizers and alcohol-free hand sanitizers effectively reduced the number of E.coli
counts (CFU) by averages of 10.2000 (92.7% reduction) and 10.2333 (93.03% reduction) respectively.
While the BC Centre for Disease Control recommends 60 percent alcohol hand sanitizers to prevent the
spread of germs, this research showed that alcohol-free hand sanitizers with sulfactants, allantoin, and
benzalkonium chloride (SAB) formula is just as effective in killing germs. Therefore, EHOs/PHIs can
educate the public and operators on the advantages and disadvantages on the two types of hand sanitizers in
preventing the spread germs during the flu season and give practical advice or guidance on which type of
hand sanitizers would be most appropriate in restaurants for example., Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2016., Peer reviewed, Alcohol-based hand sanitizers, Benzalkonium chloride, E. coli, Alcohol-free hand sanitizers
Background and the purpose: British Columbia’s Guideline for the Sale of Foods at Temporary Food Markets is a document that Environmental Health Officers’ (EHOs) and farmers’ market managers will have to consult with when determining what food products are allowed to be sold in farmers’ markets. This guideline plays a vital role because it indirectly influences EHOs’ and farmers’ market managers’ judgments and the public’s risk exposure to potentially hazardous foods (PHFs) in farmers’ markets. It is necessary to evaluate and compare BC’s guideline with other provinces’ to see where it sits in the spectrum with respect to its permissibility in allowing the sale of PHFs in farmers’ markets, perhaps contributing to the further revision or development of the farmers’ markets guideline or policy.
Methods: An online Google Docs survey consisting of 20 questions was created to ask farmers’ market managers from British Columbia and other provinces in Canada whether their farmers’ markets allow the sale of the five food types: poultry, shell egg, sauerkraut, unpasteurized juice/cider and cheese and how these foods are handled and stored.
Results: There were 56 farmers’ market managers who participated in this survey (46% from BC and 54% from outside BC). Chi-square results had p-values greater than 0.05 for all the five surveyed categories. Two-tail t test results had p-values less than 0.05 in the raw poultry and sauerkraut categories.
Discussion: Although no association between the location of farmers’ markets in Canada and the sale of the five surveyed food categories, BC farmers’ market managers disallowed the sale of raw poultry and unpasteurized juice more often than markets outside BC whereas fewer BC farmers’ market managers disallowed the sale of eggs and cheese when compared to markets outside BC. A significant difference in the handling and storage practices of raw poultry and sauerkraut was identified between farmers’ market managers in BC and outside BC. Also, BC’s managers were shown to have safer food handling practices to raw poultry, sauerkraut and unpasteurized juice than managers from outside BC.
Conclusion: The types of foods sold in BC and outside BC appeared similar as this survey found no differences between the five surveyed PHF categories allowed for sale. However, handling practices of these foods did vary, and that might be associated with guidelines, or with farmers’ market manager knowledge. Of concern, BC farmers’ market indicated that eggs and juices were sourced and made on farms. These two categories required
more attention and food safety awareness from both EHOs and farmers’ market managers. Overall, the survey responses reaffirmed that review and approval for the sale of potentially hazardous food from EHOs and scrutiny from farmers’ markets managers must be in place to ensure public’s safety as well as minimizing public’s risk exposure to improperly handled PHF sold in farmers’ markets., Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2017., Peer reviewed, Guideline for the Sale of Foods at Temporary Food Markets, Farmers’ market, Potentially hazardous food, British Columbia
Objectives: There is an increasing desire in the culinary industry to use sous vide to prepare meals at low internal temperatures to enhance flavour, texture, and quality. The sous vide method uses specific time and temperature combinations to allow for sufficient microbial destruction. The BCCDC’s Guidelines for Restaurant Sous Vide Cooking Safety in British Columbia suggests time and temperature combinations to help ensure that the required log10 reductions of pathogens are achieved. Concerns for public safety arise when chefs deviate from the guidelines, and therefore may not achieve the appropriate log10 reductions. This study looked at a commonly used sous vide duck breast recipe and determine whether appropriate the appropriate log10 reductions were met. It also examine the efficacy of the sear step and resting period in achieving the log10 reductions.
Methods: After calibration, two batches of 15 duck breasts were prepared using the sous vide method for 80 minutes at 58ºC, the breasts were then seared on a 200°C frying pan for 2 minutes each side, and then subjected to a 4 minute rest period at room temperature. The internal temperature of the breasts was continuously measured using SmartButton thermometers. This data was entered into the AMI Process Lethality Determination Spreadsheet to calculate the log10 reductions. The log10 reductions were analyzed using a one-sample t-test to assess whether the recipe achieved the required 7.0 log10 reductions.
Results: The results showed 14% of the 29 duck breasts achieved a 7.0 log10 reduction after the sous vide step of 80 minutes at 58 ºC. The null hypothesis (Ho: measured log10 reductions of duck breasts = 7.0 log10 reductions) was rejected with 100% power and a p-value of 0.00. The mean was 5.13, therefore it seems as though the log10 reductions were significantly lower than 7.0 log10 reductions. After the sear and the resting period, 52% of 27 duck breasts achieved a 7.0 log10 reduction. Statistical analyses showed that the null hypothesis could not be rejected. The p-value was 0.97 and the power was 0.413. Disregarding cumulative effects, the median log10 reductions achieved only by the sear step was 0.43, and the median log10 reductions achieved solely by the resting period was 0.35.
Conclusion: Due to lack of normality one cannot confidently say this recipe will achieve 7.0 log10 reductions. However, due to the high log10 reductions achieved, it seems plausible for another recipe to provide adequate log10 reductions while maintaining acceptable quality. The sous vide step should be used for the majority of the log10 reductions. Due to a wide variability in the results, the sear and resting period should only be used for small increases in log10 reductions., Peer-reviewed article, Published., Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2017., Peer reviewed, Sous vide, Duck breast, Temperature, SmartButton, Public health, Sear, Foodborne illness