Pathogens in Food
Although the US has one of the safest food supplies in the world, Americans still suffer from foodborne illnesses. According to the CDC, an estimated 48 million people get sick, 128,000 are hospitalized, and 3,000 die from foodborne diseases each year in the United States.
What causes foodborne illness?
To get sick from a foodborne illness, we have to eat foods or beverages that are contaminated with harmful agents. These are mostly caused by disease-causing microbes, or pathogens, such as viruses, bacteria, parasites, or molds. Think E. Coli, salmonella, and norovirus (on cruise ships), which are usually the ones that we hear about in the media. This foodborne illness chart
Actions lists the most common pathogens, their incubation period and symptoms. As you go through this chart, think about strategies to prevent these diseases in an ECE setting, which would also apply in a home setting.
Now, pathogens are live microorganisms that when ingested, will continue to grow and multiply in our intestines, thereby causing an infection. The good news is that these can be destroyed by cooking, which is why cooking food to the appropriate temperature is very important in preventing foodborne illness. However, in some cases, it’s not ingesting a pathogen that causes illness, instead it’s consuming a chemical or a toxin, which cannot necessarily be killed by cooking. Examples of chemical hazards are fertilizers, sanitizers, cleaning agents that foods may come in contact with. Toxins may be something that is naturally present in the food, or it’s produced by bacteria or fungi. An example would be E. Coli O157:H7 which produces the Shiga toxin, which can be deadly.
How does food become contaminated?
What is the role of government?
The government sets standards and regulations for how food should be handled. There are several government agencies: the Environmental Protection Agency (EPA), US Dept. or Agriculture (USDA) and the Food and Drug Administration (FDA), that regulate the use of additives, agricultural chemicals, inspect farms, food processing and storage facilities, monitor domestic and imported foods for contamination, and investigate outbreaks of foodborne illness, with the most recent one being the recall of red onions for possible contamination with salmonella.
For more information on food recalls, visit The USDA’s Food Safety and Inspection ServiceLinks to an external site.
What is the role of food manufacturers and retailers?
The Hazard Analysis Critical Control Point (HACCP) system helps prevent foodborne illness. At every step of food production, processing, and transport, potential sources of contamination are identified and checkpoints are established to prevent illness. These critical control points, such as controlling how food is stored and how it’s cooked, are monitored and corrected, if needed, to prevent or eliminate contamination. More on the HACCP system in the next section.
What should we, as consumers, do to prevent foodborne illness?
Even though government, food manufacturers, and retailers have a responsibility in ensuring a safe food supply, once food is in our homes, it’s ultimately up to us to practice safe food handling. In this week’s discussion board assignment you will have to consider your own food preparation habits and determine how well you’re protecting your family against foodborne illness. In addition to our textbook, the section on what consumers can doLinks to an external site. and the additional videos in this module go over how to minimize contamination risks.
https://www.airforcemedicine.af.mil/News/Photos/igphoto/2001954890/
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Foodborne Illness Foodborne illness is a serious threat to health. Sometimes called “food poisoning,” foodborne illness is a common public health problem that can result from exposure to a pathogen or a toxin via food or beverages. Raw foods, such as seafood, produce, and meats, can all be contaminated during harvest (or slaughter for meats), processing, packaging, or during distribution, though meat and poultry are the most common source of foodborne illness. For all kinds of food, contamination also can occur during preparation and cooking in a home kitchen or in a restaurant. For example in 2009, the Marshall Islands reported 174 cases presenting with vomiting and diarrhea. After an epidemiological investigation was completed, they identified the cause to be egg sandwiches that had been left at room temperature too long resulting in the growth of foodborne toxins in the egg sandwiches.1
In many developing nations, contaminated water is also a major source of foodborne illness. Many people are affected by foodborne illness each year, making food safety a very important issue. Annually, one out of six Americans becomes sick after consuming contaminated foods or beverages.2 Foodborne illness can range from mild stomach upset to severe symptoms, or even fatalities. The problem of food contamination can not only be dangerous to your health, it can also be harmful to your wallet. Medical costs and lost wages due to salmonellosis, just one foodborne disease, are estimated at over $1 billion per year.
At Risk Groups
No one is immune from consuming contaminated food but, whether you become seriously ill depends on the microorganism, the amount you have consumed, and your overall health. In addition, some groups have a higher risk than others for developing severe complications to foodborne disease.
Who is most at risk? Young children, elderly people, and pregnant women all have a higher chance of becoming very sick after consuming contaminated food. Other high-risk groups include people with compromised immune systems due to HIV/AIDS, immunosuppressive medications (such as after an organ transplant), and long-term steroid use for asthma or arthritis. Exposure to contaminated food could also pose problems for diabetics, cancer patients, people who have liver disease, and people who have stomach problems as a result of low stomach acid or previous stomach surgery. People in all of these groups should handle food carefully, make sure that what they eat has been cooked thoroughly, and avoid taking any chances that could lead to exposure.
2 Foodborne Illnesses and Germs. (2018). Centers for Disease Control and Prevention. Updated January 23, 2018.
1 Thein CC, Trinidad RM, Pavlin B. (2010). A Large Foodborne Outbreak on a Small Pacific Island. Pacific Health Dialogue, 16(1).
https://www.cdc.gov/foodsafety/foodborne-germs.html
https://www.ncbi.nlm.nih.gov/pubmed/20968238
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Causes of Foodborne Illness
There are many myths about foodborne illness and food poisoning:
Myth Fact
1. A food with enough pathogens to make you sick will look, smell, or taste bad.
1. A food with enough pathogens to make you sick may look, smell, or taste good.
2. Really fresh food cannot make people sick. 2. Really fresh food can cause food poisoning if it is not properly handled.
3. Only dirty kitchens can make people sick. 3. Even clean kitchens can make people sick.
4. Properly cooked food can never cause food poisoning.
4. Food poisoning can occur even when foods are properly cooked.
Table 2.1 Food poisoning myths. Source: The BC Cook Articulation Committee. Chapter 3. Causes of Foodborne Illness. Food Safety, Sanitation and Personal Hygiene. CC BY 4.0
Foodborne illnesses can be caused by any of: ● Contaminants ● Improper food handling practices ● Food allergies
Understanding each of these is critical in ensuring that food safety is maintained.3
Food contaminants can be: ● Chemical, such as cleaning agents or pesticides ● Physical, such as hair, bandages, or glass ● Biological, such as pathogens and microbes introduced from infected workers,
unsanitary work surfaces, or contaminated water
Biological causes of foodborne illness
Biological contaminants are by far the greatest cause of illness. Many of the risks associated with biological contaminants can be controlled or removed by effective food handling practices, so it is critical that the safe food handling and prevention procedures be followed.
Microbes are all around us. They are living things, often too small to be seen without a microscope. Many microbes are beneficial, but some can cause illness or even death. These harmful microbes are called pathogens.
3 BC Centre for Disease Control. Retrieved August 3, 2022.
https://opentextbc.ca/foodsafety/chapter/causes-of-foodborne-illnesses/
https://opentextbc.ca/foodsafety/chapter/causes-of-foodborne-illnesses/
https://creativecommons.org/licenses/by/4.0/
http://www.bccdc.ca
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Bacteria
Bacteria are present in many of the foods we eat and the body itself. Most bacteria are not harmful, and some are even very beneficial to people, but some types of bacteria are pathogenic and can cause illness. Campylobacter, E.coli, Listeria, and Salmonella are examples of pathogenic bacteria. Foods that contain these bacteria must be handled correctly and cooked appropriately.
Figure 2.2. Salmonella. Source: Image by NIH NIAID / CC BY 2.0
Viruses
Viruses frequently cause illness, and are found in food, but do not grow or multiply in food. Most foodborne illness caused by viruses happens because the person handling the food has transmitted the virus to the food through improper food handling or poor sanitation. The most common form of contamination from handled foods is the norovirus, which is also known as the Norwalk-like virus, or the calicivirus. Sources include raw shellfish from polluted water, salads, sandwiches, and other ready-to-eat foods handled by an infected person. The norovirus causes gastroenteritis and within one to three days it leads to symptoms, such as nausea, vomiting, diarrhea, stomach pain, headache, and a low-grade fever.
https://commons.wikimedia.org/wiki/File:Salmonella_Bacteria_(5613656967).jpg
https://creativecommons.org/licenses/by/2.0/deed.en
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Figure 2.3. Viruses in the Human Body. Source: Image by Allison Calabrese / CC BY 4.0
Parasitic Protozoa
Food-contaminating parasitic protozoa are microscopic organisms that may be spread in food and water. Several of these creatures pose major problems to food production worldwide. They include Anisakis, microscopic worms that invade the stomach or the intestines. Sources of this parasite include raw fish. This parasite can result in the Anisakis infection, with symptoms that begin within a day or less and include abdominal pain, which can be severe.
Cryptosporidium lives in the intestines of infected animals. Another common source is drinking water, when heavy rains wash animal wastes into reservoirs. One major problem with this pathogen is that it is extremely resistant to disinfection with chlorine. Cryptosporidium causes the disease cryptosporidiosis, with symptoms that begin one to twelve days after exposure and include watery stools, loss of appetite, vomiting, a low-grade fever, abdominal cramps, and diarrhea. For HIV/AIDS patients and others with weakened immune systems, the disease can be severe, and sometimes can lead to death.
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Fungi
Fungi grow on decaying organic matter. Many fungi are harmless or beneficial, but some, such as mold that grows on spoiled food, can be harmful and remain even after cutting or scraping the visible mold off the food.
Figure 2.4. Moldy nectarines. Roger McLassus 1951 / CC BY-SA 3.0
Warm, humid, or damp conditions encourage mold to grow on food. Molds are microscopic fungi that live on animals and plants. No one knows how many species of fungi exist, but estimates range from ten- to three-hundred thousand. Unlike single-celled bacteria, molds are multicellular, and under a microscope look like slender mushrooms. They have stalks with spores that form at the ends. The spores give molds their color and can be transported by air, water, or insects. Spores also enable mold to reproduce. Additionally, molds have root-like threads that may grow deep into food and be difficult to see. The threads are very deep when a food shows heavy mold growth. Foods that contain mold may also have bacteria growing alongside it.
Some molds, like the kind found in blue cheese, are desirable in foods, while other molds can be dangerous. The spores of some molds can cause allergic reactions and respiratory problems. In the right conditions, a few molds produce mycotoxins, which are natural, poisonous substances that can make you sick if they are consumed. Mycotoxins are contained in and around mold threads, and in some cases, may have spread throughout the food. The Food and Agriculture Organization of the United Nations estimates that mycotoxins affect 25 percent of the world’s food crops. They are found primarily in grains and nuts, but other sources include apples, celery, and other produce.
https://commons.wikimedia.org/wiki/Mold#/media/File:Moldy_nectarines.jpg
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The most dangerous mycotoxins are aflatoxins, which are produced by strains of fungi called Aspergillus under certain temperature and humidity conditions. Contamination has occurred in peanuts, tree nuts, and corn. Aflatoxins can cause aflatoxicosis in humans, livestock, and domestic animals. Symptoms include vomiting and abdominal pain. Possible complications include liver failure, liver cancer, and even death. Many countries try to limit exposure to aflatoxins by monitoring their presence on food and feed products.4
Food Intoxication and Food Infection
Have you ever had the “24-hour flu”? Probably not, because there’s no such thing. Many people who think they have the 24-hour flu have had a foodborne illness caused by some type of pathogen. A rapid reaction is normally caused by food intoxication. A slower reaction is normally caused by a food infection. Here’s how to tell the difference between the two:
● Food intoxication occurs when bacteria grow in food and produce a waste product called a toxin (poison). When the food is eaten, the toxins are immediately introduced into the body, causing a rapid reaction. Example: Staphylococcus
● Food infection occurs when food contains living pathogens that grow in the human intestinal tract after the food is eaten. Because the bacteria continue to multiply in the body and cause infection, the reaction will be slower. Example: Salmonella
Improper Food Handling Practices
The top 10 causes of foodborne illness are the following: 1. Improper cooling 2. Advance preparation 3. Infected person 4. Inadequate reheating for hot holding 5. Improper hot holding 6. Contaminated raw food or ingredient 7. Unsafe source 8. Use of leftovers 9. Cross-contamination 10. Inadequate cooking
Food Allergies
Food allergies are specific to individuals, but can be life threatening, and can be prevented by a thorough understanding of the allergy issue, knowledge of ingredients used in the preparation of foods, including pre-prepared foods, and care in ensuring separate cooking utensils, cookware,
4 US Department of Agriculture, Food Safety and Inspection Service. Molds on Food: Are They Dangerous? (2013).Updated August 22, 2013.
https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/safe-food-handling/molds-on-food-are-they-dangerous_/ct_index.
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and food preparation surfaces. Oftentimes, the smallest oversights can have serious consequences, as indicated in the example below:
A customer has indicated they have an allergy to MSG and ordered chicken strips with a sweet and sour sauce. The server tells them that the restaurant doesn’t add MSG to any of its food normally, so the order should be fine. After eating the sauce, the customer experiences tingling lips and hives. In follow up, the manager discovers that the pre-prepared sweet and sour sauce served with the chicken strips contains MSG on the list of ingredients.
This incident could have been prevented if the server was aware of all of the ingredients used in the dish.
Food Safety
A number of government agencies work to ensure food safety and to protect the public from foodborne illness. Food regulatory agencies work to protect the consumer and ensure the safety of our food. Food and drug regulation in the United States began in the late nineteenth century when state and local governments began to enact regulatory policies. In 1906, Congress passed the Pure Food and Drugs Act, which led to the creation of the US Food and Drug Administration (FDA). Today, a number of agencies are in charge of monitoring how food is produced, processed, and packaged.5
The USDA and the FDA enforce laws regarding the safety of domestic and imported food. In addition, the Federal Food, Drug, and Cosmetic Act of 1938 gives the FDA authority over food ingredients. The FDA enforces the safety of domestic and imported foods. It also monitors supplements, food labels, claims that corporations make about the benefits of products, and pharmaceutical drugs. Sometimes, the FDA must recall contaminated foods and remove them from the market to protect public health. For example, in 2011 contaminated peanut butter led to the recall of thousands of jars of a few popular brands.6 Recalls are almost always voluntary and often are requested by companies after a problem has been discovered. In rare cases, the FDA will request a recall. But no matter what triggers the removal of a product, the FDA’s role is to oversee the strategy and assess the adequacy and effectiveness of the recall.
The USDA develops and executes federal policy on farming and food. It also ensures food safety, and in particular oversees the regulation of meat, poultry, and processed egg products. The CDC tracks outbreaks, identifies the causes of food infection and intoxication, and recommends ways to prevent foodborne illness. The Environmental Protection Agency (EPA) works to protect human health and the environment. Two of its many regulatory practices in the area of agriculture include overseeing water quality and the use of pesticides.The EPA approves
6 US Food and Drug Administration. FDA 101: Product Recalls—From First Alert to Effectiveness Checks. (2011).
5 History of Food and Drug Regulation in the United States. (2010). EH.Net Encyclopedia.
http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm049070.htm
http://eh.net/?s=History+of+Food+and+Drug+Regulation+in+the+United+States
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pesticides and other chemicals used in agriculture, and sets limits on how much residue can remain on food. The FDA analyzes food for surface residue and waxes. Processing methods can either reduce or concentrate pesticide residue in foods. Therefore, the Food Quality Protection Act, which was passed in 1996, requires manufacturers to show that pesticide levels are safe for children.
The HACCP Approach
The Hazard Analysis Critical Control Points (HACCP) is a program within the food industry designed to promote food safety and prevent contamination by identifying all areas in food production and retail where contamination could occur. Companies and retailers determine the points during processing, packaging, shipping, or shelving where potential contamination may occur. Those companies or retailers must then establish critical control points to prevent, control, or eliminate the potential for food contamination. The USDA requires the food industry to follow HACCP for meat and poultry, while the FDA requires it for seafood, low-acid canned-food, and juice. HACCP is voluntary for all other food products and can be adapted to food service establishments, including schools. HACCP goes beyond inspecting finished food products. It helps to find, correct, and prevent hazards throughout the production process. These include physical, chemical, and biological hazards.
There are seven universally accepted HACCP principles:
Principle 1: Hazard analysis
A plan is laid out to identify all possible food safety hazards that could cause a product to be unsafe for consumption, and the measures that can be taken to control those hazards. For example, at the cooking step of the production process, one of the identified hazards is the survival of pathogens due to inadequate cooking time or temperature.
Principle 2: Identifying critical control points
Critical control points are the points in the production process where an action can be taken to prevent, eliminate, or reduce a food safety hazard to an acceptable level. For example, the cooking step is considered a critical control point because control measures are necessary to deal with the hazard of pathogens surviving the cooking process.
Principle 3: Establishing critical limits for each critical control point
A critical limit is the limit at which a hazard is acceptable without compromising food safety. For example, critical limits at the cooking stage include specific time and temperature for cooking the product.
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Principle 4: Establishing monitoring procedures for critical control points
Highly detailed monitoring activities are essential to make sure the process continues to operate safely and within the critical limits at each critical control point. For example, monitoring procedures at a cooking critical control point could include taking the internal temperature of the product with a specialized thermometer.
Principle 5: Establishing corrective actions Actions must be taken to bring the production process back on track if monitoring indicates that deviation from critical limits has occurred. In food production, correcting problems before end-stage production is far more effective than waiting until a product is finished to test it. For example: If the required internal temperature has not been reached, a corrective action would require that the product be cooked further. If the cooking temperature cannot be reached, another corrective action would call for the product to be held and destroyed.
Principle 6: Establishing verification procedures
Verification means applying methods, procedures, tests, sampling and other evaluations (in addition to monitoring) to determine whether a control measure at a critical control point is or has been operating as intended. Verification activities also ensure that the monitoring and the corrective actions are done according to a company’s written HACCP program. For example, testing and calibrating thermometers is a verification procedure that is important to ensure accurate readings. The easiest way to test a thermometer’s accuracy is by submerging the probe into a pot of boiling water. If it does not read 100˚C (212˚F) then the thermometer must be adjusted to read the correct temperature.
Principle 7: Record keeping
The company must keep records to demonstrate the effective application of the critical control points and assist with official verification (which is done in Canada by the Canadian Food Inspection Agency). Records must be established to document the monitoring and verification results as well as all information and actions taken in response to any deviations found through monitoring and verification. For example, the employee responsible for monitoring a cooking critical control point completes a cooking log sheet. This sheet includes the date, the start and finish time, the temperature, and the employee’s signature. If a deviation has occurred in the production process, the responsible employee records the details in a deviation log book.
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Preventing Foodborne Illness
Food-handling and Storage Procedures Proper food handling and storage can prevent most foodborne illnesses. In order for pathogens to grow in food, certain conditions must be present. By controlling the environment and conditions, even if potentially harmful bacteria are present in the unprepared or raw food, they will not be able to survive, grow, and multiply, causing illness.
There are six factors that affect bacterial growth, which can be referred to by the mnemonic FATTOM:
1. Food 2. Acid 3. Temperature 4. Time 5. Oxygen 6. Moisture
Each of these factors contributes to bacterial growth in the following ways: ● Food: Bacteria require food to survive. For this reason, moist, protein-rich foods are
good potential sources of bacterial growth. ● Acid: Bacteria do not grow in acidic environments. This is why acidic foods like lemon
juice and vinegar do not support the growth of bacteria and can be used as preservatives
● Temperature: Most bacteria will grow rapidly between 4°C and 60°C (40°F and 140°F). This is referred to as the danger zone (see the section below for more information on the danger zone).
● Time: Bacteria require time to multiply. When small numbers of bacteria are present, the risk is usually low, but extended time with the right conditions will allow the bacteria to multiply and increase the risk of contamination
● Oxygen: There are two types of bacteria. Aerobic bacteria require oxygen to grow, so will not multiply in an oxygen-free environment such as a vacuum-packaged container. Anaerobic bacteria will only grow in oxygen-free environments. Food that has been improperly processed and then stored at room temperature can be at risk from anaerobic bacteria. A common example is a product containing harmful Clostridium botulinum (botulism-causing) bacteria that has been improperly processed during canning, and then is consumed without any further cooking or reheating.
● Moisture: Bacteria need moisture to survive and will grow rapidly in moist foods. This is why dry and salted foods are at lower risk of being hazardous.
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Identifying Potentially Hazardous Foods (PHFs) Foods that have the FATTOM conditions are considered potentially hazardous foods (PHFs). PHFs are those foods that are considered perishable. That is, they will spoil or “go bad” if left at room temperature. PHFs are foods that support the growth or survival of disease-causing bacteria (pathogens) or foods that may be contaminated by pathogens. Generally, a food is a PHF if it is:
● Of animal origin such as meat, milk, eggs, fish, shellfish, poultry (or if it contains any of these products)
● Of plant origin (vegetables, beans, fruit, etc.) that has been heat-treated or cooked ● Any of the raw sprouts (bean, alfalfa, radish, etc.) ● Any cooked starch (rice, pasta, etc.) ● Any type of soya protein (soya milk, tofu, etc.)
PHF Non-PHF
Chicken, beef, pork, and other meats Beef jerky
Pastries filled with meat, cheese, or cream Bread
Cooked rice Uncooked rice
Fried onions Raw onions
Opened cans of meat, vegetables, etc. Unopened cans of meat, vegetables, etc. (as long as they are not marked with “Keep Refrigera
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