Would those Nigerians benefit from B.C.'s FOODSAFE program?

Yesterday, I wrote about food handling practices in street food vendors in Nigeria, and how the research suggested that they food handlers would be well-served by some formal education and training, potentially provided or designed by the government for quality and consistency assurance. B.C. has such a program in place, and last year a group of researchers from one of the province's regional health authorities and the B.C. Centre for Disease Control did a study to determine the level of success of the program.

The researchers did a telephone survey, similar to that performed by the artisan cheese researchers mentioned previously, and looked at worker's knowledge and attitudes about food safety, as well as their (self-reported) hand washing practices. It's worth noting, before we get too far in, that in 2013, once you took FOODSAFE, you were certified for life. There was no expiry date on the certification, and no upgrades or re-training was required.

Unsurprisingly, the research found that workers with FOODSAFE training had scores that were "significantly higher" than untrained workers, and that they also had "significantly better hand washing practices". They also found that after 15 years of being certified, knowledge scores "significantly decreased". It's worth noting that this study interviewed nearly 700 individuals to achieve their data, as compared to the relatively low "n" value of the artisan cheese study.

Linear regression model showing years since
FOODSAFE taken (McIntyre, et al. 2013)

While the fact that trained FOODSAFE workers had a better grasp on food handling and hygiene practices, and hand washing techniques is not at all surprising, it was interesting to note the statistically significant trend in knowledge loss over time. As the regression model to the right shows, the longer it had been since FOODSAFE was taken, the worse the knowledge scores were. The provincial authorities took notice of this study: as of July, 2013 (this study was published in March, 2013), all FOODSAFE certifications have a five year expiry date (for those taken before July, 2013, the expiry date is July, 2018).

The study results mimic what other research has shown: specific, formal, food handling education increases the skills and abilities of workers to provide safe food to consumers. However, it also shows that just giving the education isn't enough to maintain the knowledge base; there is no "set it and forget it" approach that will maintain public health. When considering the quandary of the Nigerians, and their demonstrated need for food handling and hygiene training for street vendors, it's worth keeping the need for recurring training in mind. Granted, one-off training is better than nothing, but it's clearly not the best approach.

Source: McIntyre, L., Vallaster, L., Wilcott, L., Henderson, S.B., Kosatsky, T. (2013). Evaluation of food safety knowledge, attitudes and self-reported hand washing practices in FOODSAFE trained and untrained food handlers in British Columbia, Canada. Food Control, 30, 150-156.

Street food in Nigeria: how safe is it?

Street food is becoming more popular throughout the world. It's not just us first-world people who watch "The Great Food Truck Race" on the Food Network, but globally people are seeking new ways to provide inexpensive, ready-to-eat food products to consumers on the go.

Typically, reducing a food service into a "mobile" location brings with it some inherent food safety challenges: new electricity sources need to be identified, water usage has to be limited to that which can be contained in freshwater and grey water tanks, there's not a lot of storage space, etc. With a good food safety plan, all of these challenges can be reduced. However, therein lies the rub: do mobile food service operators have the food safety acumen to develop a good food safety plan?

A group of Nigerian researchers looked to answer this very question by surveying 160 street food vendors to study food safety behaviors and hygiene practices. What they found wasn't great, if I'm being honest. Nothing in the study made me want to hop aboard a flight to southwestern Nigeria for some street meat. Nearly 62% of respondents had no formal food safety training at all, which was reflected in their hygiene practiced and attitudes toward keeping consumers safe. A stunning 3.8% of respondents "always" store food in the refrigerator, while 76% don't store food at refrigerated temperatures, and 16% don't have any food storage facilities at all.

In terms of personal hygiene, only 17% of respondents "always" washed their hands after using the toilet (though 79% responded that they did so "often"). Unfortunately, 77% of respondents admitted to using a reusable household towel to dry their hands after washing, instead of single-use paper towel.

Given the hygiene behaviors identified during the survey, it's very likely that there's a correlation between worker knowledge on how to prevent food-borne illnesses and formalized food safety training. While socioeconomic factors can reduce an individual's access to this type of training, and their ability to take time away from the workforce to participate, some sort of state-funded option could go a long way toward correcting some of these behaviors. Further, inspections and legislation surrounding street food (full disclosure: I don't know what's already in place in Nigeria) could ensure that vendors have refrigerated storage where necessary, and access to soap and paper towels for hand washing.


Source: Aluko, O.O., Ojeremi, T.T., Olaleke, D.A., & Ajidagba, E.B. (2014). Evaluation of food safety and sanitary practices among food vendors at car parks in Ile Ife, southwestern Nigeria. Food Control, 40, 165-171.

How deep does the E. coli go?

The B.C. Sewerage System Regulation (B.C. Reg. 326/2004) restricts individuals from placing sewerage systems within 30m from a well supplying a domestic water system, unless a "professional" provides written confirmation that doing so would not cause a health hazard. While setting a minimum setback level gives sewage practitioners and homeowners a baseline for ensuring the safety of their water supply (and that of their neighbors), it doesn't take into account the multitude of factors that can limit or extend the transport of disease-causing bacteria from a sewage system to a water system.

While "professionals" (essentially engineers) can reduce this setback distance, it's not clear how much research and information gathering goes into doing so. In my experience, professionals will provide support for a reduced setback because of secondary or tertiary treatment methods, or because they've looked at the soils and feel that lateral transport is going to be minimal. A study in last month's issue of the Journal of Environmental Health looked at the ability of E. coli to move through sandy loam soil (specifically that from North Carolina) to a water table in situ. They looked at 30cm, 45cm, and 60cm vertical separation between ground level and the water table, and took samples daily to identify whether those individual soil separation distances were sufficient to reduce the load of E. coli prior to the effluent coming into contact with the water.

Using a 64% sand / 30% silt / 6% clay mixture of soil (that was obtained in the field by the researchers), the researchers applied 200mL of an artificial wastewater solution to each soil column daily. The artificial wastewater (which contained nutrients like potassium, sodium, and phosphate) was spiked with E. coli that was obtained from human urine. With this application, they found that 30cm and 45cm of vertical separation were inadequate to mitigate the bacterial content to acceptable levels, with 45cm reducing the levels somewhat, but not below the recommended standard of 200cfm/100mL. 60cm of vertical separation, on the other hand, was found to be most efficient at removing E. coli to levels where the water table would not be adversely affected.

While this research was done with a specific soil type, and did not include extenuating factors that could impact the amount of bacteria that was able to move through the soil, it does provide some great data on what sort of vertical separation is required when designing onsite sewerage systems. It's the type of relatively low-cost research that should be done more often by both regulators and practitioners to ensure that the best sewerage systems (and those that are most cost effective) are being installed in areas that are potentially sensitive. When "professionals" (as defined in the Regulation) are determining whether or not to reduce the minimum setback to a well, this is the type of data that should be consulted prior to making that determination. One can use mathematical models to determine rates of flow, but they might not adequately determine the actual decrease in bacterial concentrations. Having actual in situ research that shows how wastewater moves through a specific soil composition, and how effective it is at reducing bacteria, would give professionals the confidence to reduce minimum setbacks without putting themselves at any professional liability risk.

Source: Amoozegar, A., Graves, A., Lindbo, D., Rashash, D., & Stall, C. (2014). Transport of E. coli in a sandy soil as impacted by depth to water table. Journal of Environmental Health, 76(6), 92-100.

Food safety of artisan cheese in Ontario

There have been a couple notable outbreaks associated with cheese in Canada in the past: Gort's Gouda had the recent (and well-publicized) outbreak of E. coli, 2002 and 2008 both had outbreaks of Listeria associated with both raw and pasteurized cheese products, and 1998 had a nation-wide Salmonella outbreak which was traced back to cheese found in commercially-available lunch packs. For the most part, commercially-produced cheese items are quite safe. They're made with pasteurized milk products, and undergo processing that's well-studied and well-documented. In B.C., the B.C. Centre for Disease Control has dairy specialists on-staff who routinely inspect cheese plants for best practices and adherence to policies and guidelines.

There is also a growing movement for "local" and "artisan" products, which include cheeses. To determine the perceptions around food safety and attitudes about "food safety management programs" in cheese making, a group of researchers from the University of Guelph in Ontario put together an interview for artisan cheesemakers in the area. Their sample size was pretty small (of 50 cheesemakers that were identified, they were only able to get 11 to agree to participate, and of those, only 6 would let their employees speak with the researchers), but the interview questions were based on recommendations from existing research and incorporated a "Risk Assessment Framework".

Using private, anonymous telephone interviews, the researchers spent approximately 30 minutes speaking with each of the employees and managers from the cheese companies. While they found that nearly all of the respondents were aware of biological risks to food safety in cheese manufacturing, most perceived chemical and physical hazards as a low concern. Of all potentially hazardous biological agents, Listeria was named as the main one, due to its ability to multiply at fridge temperatures, its prevalence in raw milk, and because of awareness from past outbreaks. Interestingly, more than half of the respondents were proponents of using raw milk in cheese manufacturing because of the perceived increase in product quality, customer demand, and the ability of European countries to do so safely.

In terms of risk assessment and mitigation, all respondents were aware of their individual company's biosecurity policies and procedures (such as putting on clean boots before entering the facility), and typical sanitation regimes. However, more than half of those interviewed expressed concerns with the cost of these risk management programs, including the cost of having workers performing "excessive documentation" rather than being on the production floor making cheese. The respondents also spoke to the cost of formal education around best practices and food safety, but realized the value of these education programs, and felt that the cost was outweighed by the benefits they provide. When asked about risk communication, several of those interviewed stated that they didn't think the public was concerned about the safety of their cheese, and that they cared more about "cheese quality".

While the results of this study show that most of those interviewed recognize bacteriological concerns in cheese manufacturing, it also showed that there is still the need for further education around chemical and physical contaminants. Further, while the respondents valued formal food safety education, they felt that HACCP programs took too much time and weren't efficient, especially in small cheese manufacturing plants where there were fewer person-hours of work to go around. There is also a recognized lack of knowledge and commitment to risk communication, with producers thinking that their consumers care more about the quality of the product than its safety.

Since this study looked at such a small subset of the food manufacturing industry (a small number of cheese manufacturers in a geographically small part of Canada), it's hard to say how indicative these results might be of the food processing industry as a whole. However, it certainly highlights how media attention to a specific area of concern (Listeria) can ensure widespread knowledge.


Source: Le, S., Bazger, W., Hill, A.R., & Wilcock, A. (2014). Awareness and perceptions of food safety of artisan cheese makers in Southwestern Ontario: a qualitative study. Food Control, 41, 158-167.

Don't flush your drugs down the toilet, please

It's fairly common knowledge that prescription medication is becoming a concern in wastewater treatment (both municipal, and on-site). The systems that are in place to treat bacteria that is common in sewage aren't set up to deal with the other metabolites that tend to make their way into wastewater. This is increasingly leading to concerns with effluent making its way into drinking water supplies (both ground water, and surface water).

What is studied less often is the impact that illicit drugs have on the quality of wastewater effluent, and how they might affect drinking water quality. These compounds in sewage effluent and influent have the ability to not only impact on public health, but also to impact on the environment. As a biologist, I can only imagine the impact that cocaine and methamphetamine would have on fish and frogs who come into contact with the contaminated water supplies!

A group of French scientists decided to look at illicit drugs in a number of sewage treatment plants to determine how efficient the systems were at reducing the levels of the drugs and their metabolites, and also to identify patterns of illicit drug use in the country. Though the patterns of drug use are certainly of public health interest, they're not really of environmental health interest (although the data could help to identify areas where better sewage treatment would be best placed). The efficacy of "normal" sewage treatment plants at removing illicit drugs from wastewater, however, is of great interest.

The scientists looked at 17 different illicit drugs and their metabolites, including cocaine, methamphetamine, opiates, and cannabis. The indicator for cannabis (THC-COOH) was found in every single influent the researchers looked at. They found morphine, major metabolites of cocaine, and methadone and its metabolites in 75% of influents, but found methamphetamine and amphetamine, heroin and its metabolites, and minor metabolites of cocaine in less than 10% of influents. The study goes on to further discuss what compounds were found in influent/effluent, and in what amounts, and how this can be related to patterns of drug usage throughout France, but as mentioned above, the environmental health concern is more about how efficient the sewage treatment plants are in removing the drug compounds.

While THC-COOH was found in all of the influent samples, it was also noted to be the easiest of the illicit drugs to remove, regardless of sewage treatment plant technology. Methadone and its metabolite EDDP, on the other hand, appeared to be very difficult to remove from the wastewater. Falling somewhere in between were cocaine and its metabolites, and morphine. Based on the data, it appeared as though low-load activated sludge was more effective at removing the drug compounds than medium-load activated sludge or biofilters (likely due to the longer retention time associated with low-load activated sludge).

The results of the study should be of interest to public health practitioners, and to those involved with making decisions surrounding wastewater treatment. Treatment methods that are common in municipal sewage treatment plants just aren't effective for a large number of illicit drugs and their metabolites. Performing similar "sewage epidemiology" studies in specific geographic regions would allow local governments to identify the compounds of concern in their specific area, and work on identifying treatment methods that may be somewhat more successful than activated sludge. From a terrestrial biology perspective, working together with public health practitioners could lead to a mutually beneficial outcome: reduction of illicit drug metabolites in sewage effluent will lead to safer drinking water, and safer habitats for aquatic and terrestrial animals alike.


Source: Nefau, T., Karolak, S., Castillo, L., Boireau, V., & Levi, Y. (2013). Presence of illicit drugs and metabolites in influents and effluents of 25 sewage water treatment plants and map of drug consumption in France. Science of the Total Environment, 461-462, p.712-722.