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Foodborne Illness

06.jul.05, Food Safety Network, Food Safety Network

Introduction

Foodborne illness outbreaks, traced to a variety of different foods, can occur anywhere in the world. Health Canada tracks outbreaks and publishes the statistics in their annual report "Foodborne and Waterborne Disease in Canada". It is estimated that for every 1 case of foodborne disease reported 350 cases are unreported. The number of people in Canada who contract foodborne illness per year is estimated to be 2.2 million.

Food safety is an increasingly important public health issue. Governments all over the world are intensifying their efforts to improve food safety in response to an increasing number of food safety problems and rising consumer concerns.

Foodborne illnesses are defined as diseases, usually infectious or toxic in nature, and caused by agents that enter the body through the ingestion of food. Every person is at risk of foodborne illness.

Magnitude of foodborne illness

Foodborne diseases are a widespread and growing public health problem, both in developed and developing countries.

* Most foodborne diseases are sporadic and often not reported. Foodborne disease outbreaks have the potential to affect a large number of people. For example, in 1994, an outbreak of salmonellosis due to contaminated ice cream occurred in the USA. This outbreak affected an estimated 224,000 persons. In 1988, an outbreak of hepatitis A, resulting from the consumption of contaminated clams, affected approximately 300,000 individuals in China.

*Listeriosis and pathogenic E. coli have emerged over the past two decades as important foodborne diseases. The frequency of these outbreaks is relatively low, but the health effects can be severe and life threatening to the young, elderly, and immuno-compromised.

Pathogenic Escherichia coli strains, such as E. coli O157:H7, produce a potent (vero-) toxin which causes haemorrhagic infections in the colon, resulting in bloody diarrhea. Further life-threatening complications may evolve such as kidney failure. E. coli O157:H7 outbreaks are commonly linked to undercooked ground beef, however sprouts, lettuce and unpasteurized juice have also caused outbreaks.

Listeria monocytogenes is the cause of listeriosis which has a fatality rate of up to 30%. Infection can result in meningitis. Listeria is a concern for pregnant women. In the first 3 months of pregnancy listeriosis can cause spontaneous miscarriage and later in pregnancy it can result in a baby that is stillborn or very ill. Many types of foods have been implicated in listeriosis cases. Often a long refrigeration period seems to have contributed to outbreaks as the bacteria can survive and grow at low temperatures for long periods of time.

* Cholera is a major public health problem in developing countries causing enormous economic losses. The disease is caused by the bacterium Vibrio cholerae. Water and contaminated foods can be the vehicle of infection. Rice, vegetables, millet gruel and various types of seafood have been implicated in outbreaks of cholera. Symptoms may include abdominal pain, vomiting and profuse watery diarrhoea. Without proper fluid replacement, these symptoms may lead to severe dehydration and possibly death.


Other food safety problems:

* Naturally occurring toxins, such as mycotoxins, marine biotoxins, cyanogenic glycosides and toxins occurring in poisonous mushrooms can cause severe intoxication. Mycotoxins, such as aflatoxin and ochratoxin A, are found at measurable levels in many staple foods; the health implications of long-term exposure of such toxins are poorly understood.

* Bovine spongiform encephalopathy (BSE, or "mad cow disease"), is associated with variant Creutzfeldt-Jakob Disease (vCJD) in humans. Consumption of bovine products containing brain tissue is the most likely route for transmission of the agent to humans.

* Persistant organic pollutants (POPs) are compounds that accumulate in the environment and the human body. Examples of these chemicals are dioxins and PCBs (polychlorinated biphenyls). Dioxins are unwanted byproducts of certain industrial processes and waste incineration. Exposure to POPs may result in a wide variety of adverse effects in humans.

* Metals, such as lead and mercury, can cause neurological damage in infants and children. Exposure to cadmium can cause kidney damage and is usually seen in the elderly. These (and POPs) may contaminate food through pollution of air, water and soil.


Costs of foodborne diseases

* Food contamination creates an enormous social and economic burden on communities and their health systems. In the USA, diseases caused by the major pathogens alone are estimated to cost up to $35 billion US annually (1997) in medical costs and lost productivity. The re-emergence of cholera in Peru in 1991 resulted in the loss of US $500 million in fish and fishery product exports that year.

Modern intensive agricultural practices contribute to increasing the availability of affordable food. The use of food additives can improve the quality, quantity and safety of the food supply. However, appropriate controls are necessary to ensure their proper and safe use along the entire food chain. Pre-market review and approval followed by continuous monitoring are necessary to ensure the safe use of pesticides, veterinary drugs and food additives.

Other challenges, which need to be addressed to help ensure food safety, include the globalization of trade in food, urbanization, changes in lifestyles, international travel, environmental pollution, deliberate contamination and natural and manmade disasters. The food production chain has become more complex, providing greater opportunities for contamination and growth of pathogens. Many outbreaks of foodborne diseases that were once contained within a small community may now take on global dimensions.


Is food handling a problem?

"Research shows that improper food handling in the home causes a major proportion of foodborne illnesses." This isn't quite true.

Of the 23,322 known cases of foodborne illness in Canada between 1990 and 1993, 18,450 or 79 per cent were of unknown origin. Of the cases of known microbiological origin, 70 per cent were traced to food service; 11 per cent were traced to the home; four per cent were retail in origin.

Data on foodborne illness cases due to mishandling reveals that of the cases of known microbiological origin, 61 per cent were due to mishandling at the food service level; 11 per cent in the home; six per cent at retail; and six per cent on farms or dairies.

Our surveillance capabilities are weak. Certainly, they are not strong enough to support statements such as, "Research shows that improper food handling in the home causes a major proportion of foodborne illnesses." We simply do not know.

For producers the point may seem academic - except that on-farm food safety programs are being contemplated and in some sectors implemented across Canada. If consumers ask producers to bolster their food safety capabilities ideally we would be able to say not only are producers enhancing consumer confidence, but that the incidences of foodborne illness are going down.


Food safety in Canada

Consumer health and safety concerns continue as a major challenge to the food industry.
The 1990s have seen the emergence of microbial foodborne illnesses as a significant public health problem - and certainly as a media phenomenon. Ever since the 1993 Jack-in-the-Box outbreak of E. coli O157:H7 linked to undercooked hamburgers, there has been an explosion of health and food-related coverage extending all the way back to the farm gate. The result is that any agricultural and food production practice is now under the microscope of public scrutiny.

Canadian regulators have been slow to act. For example, in the fall of 1998, the U.S. Food and Drug Administration implemented mandatory labelling for unpasteurized apple cider and warned certain consumers not to eat alfalfa sprouts. Both of these actions were due to the occasional presence of bacterial pathogens which can make people extremely ill, especially the very young and very old.

Similar actions have not been taken by Canadian regulators, although the risk remains, irrespective of geography. This was painfully evident with the October 1998 outbreak of E. coli O157:H7 in southwestern Ontario related to unpasteurized cider; and continual outbreaks related to alfalfa and other sprouts. Yet, when the next outbreak arrives, it will be the brand name that suffers. This occurred with a samonella outbreak traced to Schneider's packaged Lunchmates. More than 800 people were affected, mostly children.

So what are the components of a great food safety system? What would allow a government-type to legitimately say that we have the safest food in the world? The answer is as complex as it seems intuitive. Here are five key components.

Effective and rapid surveillance systems
If government and consumers demand programs to enhance the safety of the food supply, there should be a system of surveillance. The numbers of sick people and of incidence of contaminated food would show whether or not a particular program is working. The FoodNet system of active surveillance in the U.S. is a good model for such a system and should be incorporated into Canadian efforts.

Effective communication about the nature of risk
It's not enough to say, "We have safe food," especially when outbreaks of foodborne illness are documented on an almost daily basis. Instead, all players in the farm-to-fork continuum including farmers, processors, distributors, retailers, consumers and others, need to talk about the risks inherent in any food production system and ways to reduce that risk.

A credible, open and responsive regulatory system
Those same players want to know what the rules are and they want those rules to be fair. Ontario Bill 87, the Food Safety and Quality Act, goes some way toward such objectives, as did the creation of the Canadian Food Inspection Agency at the federal level.

Demonstrable efforts to reduce levels of uncertainty and risk
Programs have been created to improve food safety practices on the farm, right through to the kitchen. For example, Ontario Greenhouse Vegetable Growers have worked with the Food Safety Network for the past three years to create, implement and monitor a food safety program for greenhouse cucumbers and tomatoes. On-site visits have been conducted with each of the 220 members and the primary areas of focus are water quality, worker hygiene, cleanliness of equipment, proper storage and transportation of the product. The growers group has taken a hands-on and intensive individual approach to food safety, providing information and instruction to operators on how to identify and address potential microbial issues while following Hazard Analysis and Critical Control Point (HACCP) principles.
Similar efforts have been undertaken with the processing vegetable growers in Ontario and we are now working with Ontario fruit and vegetable growers. Such programs received funding from the provincial government but were delivered by the growers themselves in conjunction with researchers in the field.

Evidence that actions match words
Having a program is nice, but discerning customers will demand the data that such a program is actually working. Regardless of who conducts the testing or inspection, such results need to be public, for researchers and others to offer a critical perspective. This will allow the effectiveness of Canadian standards with those of other countries to be compared. Problems could be identified and rectified in order to assure consumers that perhaps some food is safe.


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