If you’ve ever felt queasy following a meal or regretted trying that new restaurant several days later, you are certainly not alone. Roughly 76 million people suffer from food poisoning every year in the United States and while most of the cases result in mild discomfort and sickness, some cases can be much more severe.
Tainted food claims the lives of about 5,000 people per year and the leading cause of food-related deaths is food tainted with harmful bacteria or viruses. The most effective way to avoid food poisoning is to handle and cook foods properly and to avoid any food that has exceeded its expiration date.
Microorganisms Responsible for Food Poisoning Symptoms
Food poisoning occurs when you have consumed food that contains dangerous bacteria, viruses or parasitic organisms and the subsequent symptoms are the result of an immune response meant to remove the invading organisms from your system. The majority of foodborne illness and food-related deaths are attributed to the following eight microorganisms.
- Salmonella— most commonly associated with poultry and eggs, salmonella is one of the most well-known causes of food poisoning. Most people equate salmonella poisoning with undercooked chicken or raw eggs, but the bacteria can be found in raw fruit and vegetables, especially leafy vegetables such as lettuce and cabbage. It may also be spread through contact with someone who is infected.
- Clostridium perfringens— these bacteria can be found in the intestines and is one of the most common forms of bacteria found in tainted food. Most cases of C. perfringens contamination are due to the consumption of foods that have been left out at room temperature for too long. Once a small number of bacteria contaminate the food, they reproduce at a rapid rate and the large numbers of these bacteria are what cause humans to get sick, due to the toxicity of the waste the bacteria produce within the body.
- Campylobacter— found in raw meat, undercooked poultry, untreated water and produce, these bacteria is one of the most common causes of diarrhea. Most people make the common mistake of assuming that frozen food is free of bacteria and while cold temperatures do slow the growth and spread of bacteria, forms such as campylobacter are able to survive in extreme cold. Undercooking meats after they have been frozen is a common means by which campylobacter is spread.
- Staphylococcus aureus— commonly referred to as staph, these bacteria is actually found on our body and in our throats and is normally benign. It is when they make contact with certain food products that they multiply more rapidly and become dangerous due to their massive numbers. Salads, sandwiches and other foods that require no heat to prepare are at risk of staph contamination because the bacteria are often transferred from the food preparer’s hand to the food and not killed before consumption.
- E. coli— there are many forms of E. coli and most of them are completely harmless. Others are extremely dangerous and the cause of massive outbreaks of food poisoning that result in widespread food recalls. E. coli is most commonly found in raw meat and dairy products but can also be contracted from tainted water or any food that has had contact with feces.
- Listeria monocytogenes— this dangerous form of bacteria is able to grow at cooler temperatures, making it impervious to the most common food preservation methods and hitting victims by surprise. It can be found in deli meats, sausages, dairy products, seafood and undercooked meat and poultry. Because it can survive in ice-cold temperatures and causes a severe infection that poses a serious risk to pregnant women, young children and the elderly, foods that are discovered to be contaminated are often recalled immediately.
- Norovirus— the norovirus is one of the leading causes of food poisoning and its symptoms are often mistaken for the flu, causing many cases to go unreported or misdiagnosed. As a communicable disease, it spreads through contact with infected persons or surfaces, but it can also spread through the contamination of shellfish, fruit and vegetables and unheated foods.
- Toxoplasma gondii— unlike the other foodborne illnesses on this list, toxoplasma gondii is the result of a parasite that is transferred through raw meat that has been in contact with feces, contact with a cat that has been on contact with an infected litter box and drinking contaminated water. Symptoms of infection mimic the flu initially and then become progressively more serious. Infections can result in muscle aches, swollen lymph glands, blurred vision and red or irritated eyes. Once contracted, the disease can last for months.
The Most Common Sources of Foodborne Illnesses
With good reason, most people associate foodborne illness with improperly prepared meat and poultry. Beef, pork and chicken are by and large the most common sources of food contamination, but other sources are often ignored due to lack of education. The Center of Science in the Public Interest tracked the instances of foodborne illness in a study involving 50,000 cases to determine which foods were most likely to be sources of contamination. The top ten follow below.
- Leafy green vegetables— most people are unaware of how hospitable leafy vegetables are to bacteria. The reality is that when we consume lettuce and other leafy greens, we are feeding the good bacteria in our digestive tract and overconsumption of greens can cause gas and bloating due to the overgrowth of these bacteria. Bad forms of bacteria also consume these vegetables and tainted greens were responsible for 13,568 of the 50,000 cases studied, which is 24% of non-meat related cases.
- Eggs— caused mostly by poor handling of eggs during and after cooking rather than consumption of raw eggs, roughly 11,164 of the cases studied involved eggs. About half of the cases were the result of tainted restaurant food, calling for the need to enforce stricter standards on the quality of food being served.
- Tuna— responsible for 2,341 cases of food poisoning in the study, tuna can decay quickly after being caught and this invites numerous forms of microorganisms to contaminate the flesh before it is consumed. Many people consume tuna out of the can without cooking it, only increasing the likelihood of infection.
- Oysters— 3,409 cases involved the consumption of oysters, which is a commonly tainted seafood that is often enjoyed raw.
- Potatoes— involved in 3,659 cases, potatoes are commonly contaminated when left out for too long and not properly reheated prior to eating.
- Cheese— 2,761 cases of food poisoning involved the consumption of cheese, which may harbor listeria. Cheese is also commonly used as an ingredient in salads, sandwiches and other foods that are not heated, so its involvement may be incidental in cases where it joined other tainted foods.
- Ice cream— because listeria thrives both in low temperatures and dairy products, ice cream is one of the products most likely to harbor it. 2,594 cases in the study involved ice cream consumption.
- Tomatoes— some of the greatest outbreaks of foodborne illness have been related to tainted tomatoes, which can harbor salmonella, norovirus and other contaminants. Tomatoes were related to 3,292 of the cases included in the study.
- Sprouts— often consumed raw, sprouts may also harbor bacteria and viruses that cause food poisoning. Sprouts were consumed by 2,022 of the patients involved in the study.
- Berries— some bacteria and many forms of fungi thrive on sugar, which abounds in fruits and berries. Unsurprisingly, 3,397 of those who became ill had consumed berries.
How to Prevent Food Poisoning
It is much easier and safer to prevent food poisoning than to endure the symptoms of an infection. Following these tips will greatly reduce your chances of infection and help you prevent the spread of an outbreak.
- Wash all fruits and vegetables before preparing them. Doing so will remove the majority of bacteria and viruses that are residing on the surface, which will greatly reduce your risk of becoming ill when consuming these foods raw.
- Clean your hands thoroughly before preparing any raw food or meal that does not require heating the food. Due to the commonality of staphylococcus on our skin, contact with raw foods will spread the bacteria if we do not wash our hands prior to preparation. It only takes the introduction of a small number of bacteria to a food source to allow it to balloon into a threat.
- Use a meat thermometer to measure the internal temperature of meats prior to serving. Foodsafety.gov recommends heating ground meats, poultry, eggs and leftover portions to an internal temperature of 165 degrees while it is acceptable to cook ham, pork, steaks and lamb to a temperature of 145 degrees.
- When using a knife to cut contaminated foods such as poultry, avoid cross-contamination by keeping the utensil away from other ingredients.
- Pay attention to expiration dates and throw away food that has gone bad. It is possible for bad foods to spread contaminants to good foods in the same manner that mold moves from one object to another.