Fall is often associated with changing leaves, cooler temperatures, football games and holiday gatherings. It is also the beginning of a period when foodborne illness risks can shift significantly.
The foods served during fall celebrations create several opportunities for contamination. Large quantities of turkey, chicken, beef, stuffing, casseroles, gravies and other foods are prepared for family gatherings. Food may be transported from one location to another, placed on buffet tables and left at room temperature for extended periods. At the same time, the approach of colder weather creates conditions in which norovirus outbreaks become increasingly common.
Foodborne illness does not disappear when summer ends. Some pathogens remain a year round threat, while others become more prominent as people spend more time indoors and gather in larger groups.
CDC estimates that approximately 48 million Americans develop foodborne illness each year, resulting in about 128,000 hospitalizations and 3,000 deaths. Norovirus causes more foodborne illnesses than any other pathogen, while non typhoidal Salmonella is responsible for the most deaths among the major foodborne pathogens.
Understanding which illnesses are most important during the fall, what causes them and how they spread can help consumers reduce their risk.
1. Norovirus
Norovirus deserves particular attention as fall begins because its activity typically increases as the year progresses toward winter. Norovirus is an extremely contagious virus that causes acute gastroenteritis, producing inflammation of the stomach and intestines. Although people often call it the “stomach flu,” norovirus is unrelated to influenza.
CDC estimates that norovirus causes approximately 19 to 21 million illnesses in the United States each year. The virus is responsible for approximately 2,500 reported outbreaks annually. Although outbreaks can occur throughout the year, they are most common from November through April. That seasonality makes late fall an important transition period.
What causes norovirus?
People become infected when they swallow norovirus particles. The virus can spread when an infected person prepares food, touches food with contaminated hands, or contaminates surfaces that other people subsequently touch.
Food can also become contaminated before it reaches the kitchen. Leafy greens, fresh fruits and vegetables and shellfish, particularly raw oysters, are among foods associated with norovirus illness.
Norovirus is particularly difficult to control because very small amounts of the virus can cause illness and infected people can contaminate food even when they do not appear seriously ill.
Symptoms
Norovirus typically causes:
- Diarrhea
- Vomiting
- Nausea
- Stomach pain
Fever, headache and body aches can also occur.
Symptoms generally develop within 12 to 48 hours after exposure. Most people recover within one to three days. The greatest immediate concern is dehydration, particularly among young children, older adults and people with underlying medical conditions.
Preventing Norovirus
Handwashing is one of the most important defenses. People should wash their hands thoroughly with soap and water before preparing food and after using the bathroom or caring for someone who is sick. Alcohol based hand sanitizer should not be considered a substitute for handwashing when norovirus is involved.
People who are sick should not prepare food for others. Surfaces contaminated by vomit or diarrhea should be cleaned and disinfected promptly.
The seasonal increase in norovirus activity means these precautions become particularly important as families begin gathering indoors during Thanksgiving and the winter holidays.
2. Salmonella
Salmonella remains one of the most important foodborne bacteria throughout the year. Fall gatherings can create additional opportunities for exposure because poultry, eggs, meat and large shared meals are common components of seasonal celebrations.
CDC identifies non typhoidal Salmonella as one of the five leading causes of foodborne illness in the United States and the leading cause of foodborne illness deaths among the major pathogens.
What causes Salmonella infection?
Salmonella bacteria can contaminate a wide range of foods. Common sources include raw or undercooked chicken, turkey and other meats, eggs, unpasteurized milk and juice, and contaminated fruits and vegetables.
Fall turkey preparation deserves particular attention. Raw poultry can contain Salmonella. Handling the bird can contaminate hands, cutting boards, countertops, utensils, and other foods. The danger does not necessarily come from eating the turkey itself. Cross contamination can spread bacteria throughout the kitchen before the bird ever enters the oven.
Large holiday meals can also create temperature control problems. Food prepared several hours before guests arrive may remain at room temperature while people wait to eat.
Symptoms
Salmonella infection commonly causes:
- Diarrhea, which can sometimes be bloody
- Fever
- Stomach cramps
- Vomiting
Symptoms generally begin six hours to six days after infection.
Most people recover without specific treatment, but infection can become serious and may require hospitalization. Young children, older adults and people with weakened immune systems are at greater risk of severe illness.
Preventing Salmonella
Raw poultry should be handled carefully to prevent contamination of ready to eat foods. Do not wash raw turkey or chicken. Washing poultry can spread bacteria through splashing water.
Use separate cutting boards and utensils for raw meat and foods that will not be cooked. Wash hands with soap and water after handling raw poultry.
Most importantly, cook poultry to a safe internal temperature. A food thermometer is more reliable than judging doneness by color. Leftovers should also be refrigerated promptly rather than sitting on the dining table for hours.
3. Campylobacter
Campylobacter is another major cause of bacterial foodborne illness. CDC estimates that nearly 1.9 million people in the United States become ill from Campylobacter each year. It is the leading bacterial cause of diarrheal illness in the country.
Campylobacter infections are more common during summer than winter, meaning the overall seasonal risk generally declines as fall progresses. That does not make the pathogen irrelevant during autumn. Poultry remains a common source, and the foods associated with fall gatherings can still create opportunities for infection.
What causes Campylobacter infection?
People most commonly become infected by eating raw or undercooked poultry. Other sources include contaminated foods, untreated water, and contact with animals carrying Campylobacter.
Cross contamination is an important pathway. Raw chicken juices can contaminate a cutting board or countertop, and bacteria can subsequently be transferred to salad ingredients, bread, utensils or other foods.
Symptoms
Campylobacter commonly causes:
- Diarrhea, which may be bloody
- Fever
- Stomach cramps
- Nausea
- Vomiting
Symptoms usually begin two to five days after exposure. Most people recover within approximately a week.
Campylobacter is also notable because some infected people develop longer term complications, including irritable bowel syndrome, arthritis, and Guillain Barré syndrome.
Preventing Campylobacter
The most important protection is thoroughly cooking poultry. Consumers should also prevent raw poultry from contacting foods that will be eaten without cooking. Hands, utensils and food preparation surfaces should be washed after raw chicken or turkey is handled.
A thermometer is particularly useful because poultry can appear cooked before the interior reaches a temperature sufficient to destroy dangerous bacteria.
4. Clostridium perfringens
Clostridium perfringens is particularly relevant to fall and holiday meals because it is associated with foods prepared in large quantities and held at unsafe temperatures. CDC identifies C. perfringens among the five leading causes of foodborne illness in the United States.
Unlike many foodborne pathogens, the problem is often not simply whether food was cooked. The way food is cooled, stored and served can be equally important.
What causes C. perfringens illness?
C. perfringens bacteria can grow in foods that are cooked in large quantities and then held at temperatures that allow bacterial multiplication. Meat, poultry, gravies and other foods prepared in large batches are common sources.
Holiday gravy provides a good example. A large pot of gravy or a casserole may be prepared well before dinner and then left on a counter or buffet table. If food remains in the temperature range that permits bacterial growth for too long, C. perfringens can multiply.
Another problem occurs when large quantities of leftovers are placed into a refrigerator in a deep container. The center of the food may cool much more slowly than the surface.
Symptoms
C. perfringens typically causes:
- Diarrhea
- Stomach cramps
Vomiting and fever are not common.
Symptoms generally begin six to 24 hours after consuming contaminated food and usually last less than 24 hours. The illness can nevertheless be extremely unpleasant, particularly when several people at a holiday gathering become sick simultaneously.
Preventing C. perfringens
Temperature control is the key. Keep hot foods hot and cold foods cold. Refrigerate leftovers promptly rather than allowing them to remain on the counter for extended periods. Large quantities of food should be divided into shallow containers so that they cool more rapidly. When reheating leftovers, make sure they are heated thoroughly before serving.
These precautions are especially important during Thanksgiving, Christmas and other gatherings where large quantities of food are prepared in advance.
5. Shiga Toxin Producing E. coli
Shiga toxin producing E. coli, commonly called STEC, is another major foodborne pathogen. Some strains can cause severe illness, particularly when infection progresses to hemolytic uremic syndrome, a potentially life threatening complication that can cause kidney failure.
CDC includes STEC among the five leading causes of foodborne illness in the United States. Approximately 5 to 10 percent of people diagnosed with an E. coli infection develop hemolytic uremic syndrome.
What causes E. coli infection?
Common sources include raw or undercooked ground beef, unpasteurized milk and juice, raw vegetables, raw sprouts and contaminated water.
Ground beef is particularly relevant during fall football parties and family gatherings. A hamburger can look brown on the outside while remaining insufficiently cooked in the center. Because ground beef can distribute bacteria throughout the entire product during grinding, the interior must reach a safe temperature.
Symptoms
STEC infections can cause:
- Severe stomach cramps
- Diarrhea, which is often bloody
- Vomiting
Symptoms commonly begin three to four days after exposure.
A major warning sign is bloody diarrhea, particularly when accompanied by severe abdominal pain. People with suspected STEC infection should contact a healthcare professional. Certain treatments, including some antibiotics and anti diarrhea medications, may not be appropriate for patients with STEC because of the potential relationship with hemolytic uremic syndrome.
Preventing E. coli infection
Cook ground beef thoroughly using a food thermometer. Prevent raw ground beef from contacting foods that will not be cooked. Use separate utensils and plates for raw and cooked meat. Wash hands after handling raw ground beef.
Consumers should also pay attention to recalls involving ground beef and other products because contaminated foods can remain in household refrigerators or freezers after they have been removed from store shelves.
Listeria: Less Common but Potentially More Dangerous
Listeria monocytogenes does not rank among the five pathogens responsible for the greatest number of foodborne illnesses overall, but it deserves special attention during fall because it can cause disproportionately severe disease.
CDC describes Listeria infection as relatively rare but potentially serious. Pregnant women, newborns, adults 65 and older and people with weakened immune systems are at greatest risk.
What causes listeriosis?
Listeria can contaminate many foods. CDC identifies foods including certain soft cheeses, deli meats, hot dogs, smoked fish, raw milk and other refrigerated ready to eat products as potential sources.
One important characteristic of Listeria is that the bacteria can grow at refrigerator temperatures. That means refrigeration does not necessarily eliminate the hazard.
Symptoms
Invasive listeriosis can cause fever, muscle aches, fatigue and headache. More serious infections can cause stiff neck, confusion, loss of balance and seizures. Pregnant women may experience only mild symptoms, but infection can cause miscarriage, stillbirth, premature delivery or life threatening infection of the newborn. The seriousness of listeriosis is why people at increased risk should pay close attention to food recalls and recommendations concerning high risk foods.
Why Fall Food Preparation Creates Special Risks
The illnesses described above are not all uniquely seasonal. The important point is that fall activities can create conditions that favor particular transmission routes.
Holiday meals often involve large quantities of food. Large quantities create problems with cooling and reheating. A giant pot of soup, a large casserole, turkey, stuffing or gravy may take considerably longer to cool than smaller portions.
Fall gatherings also mean more people eating the same food. If one dish becomes contaminated, dozens of people may be exposed. Buffet service creates another challenge. Food may sit out while guests socialize, return for second helpings and continue eating over several hours.
The approach of colder weather also increases indoor gatherings. This is particularly important for norovirus because the virus spreads efficiently from person to person and through contaminated food and surfaces.
The Most Important Prevention Strategy: Control the Five Major Risks
Food safety can seem complicated because there are dozens of pathogens and numerous ways food can become contaminated. The basic principles, however, are straightforward.
Clean
- Wash hands thoroughly with soap and water before preparing food and after handling raw meat, poultry or eggs.
- Clean countertops, cutting boards and utensils.
- Handwashing is especially important when preparing food for large groups.
Separate
- Keep raw meat, poultry, seafood and eggs away from ready to eat foods.
- Do not place cooked food back onto the same plate that held raw meat unless the plate has been thoroughly washed.
- Cross contamination can occur without anyone realizing it.
Cook
- Use a food thermometer rather than relying on appearance.
- Ground meats, poultry, egg dishes and leftovers need particular attention.
- Cooking is one of the most effective ways to destroy many bacterial pathogens.
Chill
- Refrigerate perishable food promptly.
- Do not leave holiday dishes sitting at room temperature for hours.
- Large quantities should be divided into smaller, shallow containers so they cool quickly.
Stay informed
- Consumers should pay attention to food recalls and outbreak announcements.
- A contaminated product can look completely normal. It may not smell bad, taste unusual or show any visible sign of contamination.
- Checking recalls is therefore an important part of food safety.
People at Greater Risk Need Additional Precautions
Anyone can develop foodborne illness, but certain people have a higher risk of severe disease. CDC identifies adults 65 and older, children younger than 5, pregnant women and people with weakened immune systems as groups at increased risk. These individuals and the people preparing food for them should be especially careful about food handling.
Listeria presents an especially important concern for these groups. More than half of all reported Listeria infections occur among people 65 and older, according to the CDC.
People at higher risk should also take food recalls seriously and discuss food safety concerns with their healthcare providers when appropriate.
Recognizing When Foodborne Illness Requires Medical Attention
Most foodborne illnesses cause some combination of diarrhea, abdominal pain, nausea, vomiting and fever. Some infections, however, can become serious.
CDC recommends seeking medical attention for symptoms such as bloody diarrhea, diarrhea lasting more than three days, a fever above 102 degrees Fahrenheit, frequent vomiting that prevents keeping liquids down or signs of dehydration.
People should also seek medical advice when symptoms are severe or when they belong to a group at increased risk. Persistent or unusually severe illness should not simply be dismissed as a stomach bug.
Fall Is Not a Break From Foodborne Illness
The transition from summer to fall does not eliminate foodborne illness.
Some seasonal patterns change. Campylobacter infections are more common during summer than winter, while norovirus activity typically increases toward the colder months.
Other pathogens remain significant throughout the year. Salmonella can contaminate poultry, eggs and other foods. C. perfringens can multiply when large quantities of food are improperly cooled or held at unsafe temperatures. STEC can contaminate ground beef and other foods. Listeria can contaminate refrigerated ready to eat foods and can be particularly dangerous for vulnerable populations.
The foods themselves are not necessarily the problem. The risk often depends on how they are produced, stored, prepared, cooked, transported and served. That is particularly important during the fall because meals become larger and gatherings become more frequent.
Final Note
Fall food safety is ultimately about understanding how the season changes exposure opportunities.
Turkey and other poultry can introduce Salmonella and Campylobacter into the kitchen. Large pots of gravy, meat and casseroles can create conditions favorable for C. perfringens if they are improperly held or cooled. Undercooked ground beef can expose people to STEC. Refrigerated ready to eat foods can present a Listeria risk, particularly for vulnerable people. Meanwhile, the arrival of late fall brings increasing norovirus activity and more opportunities for person to person transmission during indoor gatherings.
The good news is that many of the most effective prevention measures are simple.
Wash hands. Keep raw foods separate. Cook foods thoroughly. Refrigerate perishable foods promptly. Keep hot foods hot and cold foods cold. Clean contaminated surfaces. Pay attention to recalls and public health warnings.
Fall meals should be occasions for families and friends to enjoy food together, not opportunities for a preventable illness to spread.
Understanding the pathogens that remain important during the autumn months gives consumers an advantage. Foodborne illness cannot always be detected by looking at a meal, but careful preparation and temperature control can significantly reduce the opportunity for dangerous pathogens to reach the people sitting around the table.
