What is foodborne disease and what are the control measures for foodborne illness outbreaks?

and last updated on December 11, 2020 06:05 PM


Author: Dr. Jeff Farber

Foodborne illness is caused by the ingestion of contaminated food by an individual. There are two main types of foodborne illnesses. The first, generally referred to as food poisoning, occurs when a person ingests a food that contains a foodborne pathogen and illness results. The second type is commonly referred to as “foodborne intoxication” and occurs when a pre-formed toxin, made by a microorganism, is ingested by the person, resulting in illness. Common examples of food poisoning organisms include Listeria monocytogenes, Salmonella enterica and Campylobacter spp. Examples of food intoxication include Staphylococcus aureus and Bacillus cereus intoxications, as well as the seafood toxins such as paralytic shellfish toxin/poisoning and domoic acid. Although many people think that you only have mild diarrhea, stomach cramps and/or vomiting with foodborne illness, this can be far from the truth. In fact, there can be very dangerous “sequelae” or complications arising after the initial foodborne infection. Some examples include arthritis after a Salmonella infection, neurological disorders such as Guillain-Barré syndrome after a Campylobacter infection and kidney complications/failure from hemolytic-uremic syndrome (HUS), which can occur as a result of an initial E. coli O157:H7 infection. Death can also occur after a foodborne illness. For example, in high-risk individuals, the mortality rate of a Listeria monocytogenes infection can approach close to 40% in outbreak situations, such as was observed in the deli-meat outbreak which occurred in Canada in 2008.

Control of Foodborne Illness:
Everyone has a role to play in preventing or controlling foodborne illness. This includes consumers, the food industry and governments. The food industry has the primary responsibility for producing safe food, while governments provide the regulatory oversight needed to ensure that the food industry is following the correct practices and procedures that will lead to a safe food supply.

I. Food Industry Controls
Controls performed by the food industry can generally be broken down into pre-harvest and post-harvest controls.

i) Pre-Harvest:
Recently, foodborne illnesses due to fruits and vegetables appear to be increasing. Some examples of control measures for produce that can be done at the pre-harvest stage on the farm (referred to as on-farm food safety) include the use of properly treated water, monitoring the health and hygiene of farm workers, improved on-farm sanitation, and restricting the access of livestock and other animals to crops and to surface waters. Good hygienic practices by farm workers involved in the cultivation, harvesting, processing, or packaging of fresh produce are also very important in terms of reducing the likelihood of contamination at the farm level. The availability of toilets and hand-washing facilities for farm workers is also an important control measure. Other pre-harvest examples besides the produce area, include the need for quality assurance programs at egg farms and programs to keep shellfish harvest beds free of sewage contamination.

ii) Post-Harvest:
Food companies processing ready-to-eat (RTE) food should have effective good manufacturing practices (GMPs) and a HACCP (Hazard Analysis and Critical Control Points) system in place to minimize all potential sources of food contamination. These should address the potential for foodborne pathogens such as L. monocytogenes to be present in the environment of their processing establishment. In this regard, the importance of sanitation should not be overlooked. RTE food processors should also strongly consider introducing within their food safety systems one or more validated controls for the elimination of foodborne pathogens from their products (e.g., use of a post-lethality treatment). Furthermore, environmental and end-product sampling plans and the use of microbiological testing as a verification tool to demonstrate the effectiveness of the control measures put in place to address pathogens such as L. monocytogenes are recommended. Food processing plants should also carry out regular environmental sampling to verify the effectiveness of their sanitation programs. The use of pasteurization, high-pressure processing, canning, cooking, irradiation, and other steps to kill pathogens in food processing are important tools that the food industry should be using.

iii) Foodservice:
There are many foodborne outbreaks that occur in restaurants. Examples of some control measures for restaurants include training for restaurant managers and food workers about food safety and sanitation measures, having standardized procedures and cooking protocols in place, having a certified kitchen manager on site at all times, emphasizing proper hand-washing procedures and facilities, and making sure that policies and procedures are in place to make sure that ill employees do not come into work. One can encourage food workers not to work when they are ill, for example, by providing paid sick leave.

iv) Retail:
The key factors involved in the control of foodborne pathogens at retail include the prevention of cross-contamination, practicing proper sanitation and controlling time and temperature. Cleaning and sanitizing is the number one control available to minimize the spread of pathogens at retail, while temperature is the number one control available to minimize the growth of pathogens at retail. Employee training is also critical. In China, food service workers must pass an annual health examination, and are subject to mandatory training in sanitation requirements relevant to their positions. The resulting Health Certificate is updated annually.

The following have been identified as ‘key’ components in the control of pathogens at retail, including L. monocytogenes:
i) sourcing from inspected suppliers indicates that the food has passed the initial government inspection for food safety;
ii) avoiding/minimizing contamination and cross-contamination at each stage of retail receiving and handling;
iii) cleaning and sanitizing, as mentioned above, are the number one controls available to the retail sector to minimize the spread of pathogens;
iv) temperature control is vital, as refrigeration temperatures inhibit or slow the growth of foodborne pathogens; v) the appropriate durable life should be displayed on products;
v) product rotation should be done such that foods with an earlier best-before date should be offered for sale and consumed before food with a later best-before date;
vi) employee training, including personal hygiene practices; and
vii) implementation of a HACCP-based approach to minimize the spread and growth of pathogens, including L. monocytogenes, at the retail level.

II. Consumers:
Educational material directed at the consumer should be continuously updated and evaluated for its effectiveness. Consumers should be taught the basics of food safety, for example - cook, chill, clean and separate. Cleaning anything that comes into contact with food will help eliminate bacteria and reduce the risk of foodborne illness. This includes your hands, kitchen surfaces, utensils and reusable grocery bags. It is important to keep cold food cold and hot food hot, so that your food never reaches the "temperature danger zone." This is where bacteria can grow quickly and cause food poisoning. Cooking food properly is the best way to make sure it is safe to eat. The importance of preventing cross-contamination in the kitchen should also be emphasized. For certain pathogens such as L. monocytogenes, educational efforts should be directly targeted to at-risk groups such as pregnant women, people with weakened immune systems and the elderly (> 65 years of age).

III. Government
Governments develop food safety standards and policies to help minimize the risk of foodborne illnesses. Agencies oversee the food industry to ensure that it meets its food safety responsibilities, and conduct targeted surveys of foods for specific pathogens. Governments may also conduct either passive and/or active surveillance of human illnesses, and to investigate the source of any food-related illnesses, especially when an outbreak is suspected. In addition, governments may provide reference laboratory services, perform risk-based inspections, conduct food safety investigations, and perform health risk assessments and conduct recall actions when required. Governments can also brief the medical community, public health officials, the food industry and consumers on issues related to contaminated foods and foodborne outbreak investigations, as well as to develop educational material for both consumers and the food industry.

About the Author

Dr. Jeff Farber recently stepped down as the Director of the Bureau of Microbial Hazards, in the Food Directorate of Health Canada, where he worked for over 25 years. Dr. Farber is responsible for over 150 publications and numerous book chapters, and has edited four books. He was Associate Editor of the International Journal of Food Microbiology for many years and has been on a number of journal editorial boards.

Dr. Farber has been instrumental in advancing the development of policy responses for emerging microbial food safety issues in both Canada and at a global level. Dr. Farber is a past President of the International Association for Food Protection, and a member and treasurer of the International Commission on Microbiological Specifications for Foods (ICMSF). He is also a member of the Agriculture, Food and Nutrition Working Group of the New York Academy of Sciences and was recently appointed to the USFDA Food Advisory Committee.

Dr. Farber has received numerous personal and team awards, the most recent being a Science and Technology award from the Canadian Meat Council. He recently accepted a new position, and is currently employed as a Full Professor in the Department of Food Science at the University of Guelph, in Guelph, Ontario, where he is head of the Master’s in Food Safety and Quality Assurance program and the Director of the Canadian Research Institute for Food Safety.