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Differences Between Food Poisoning & Flu

author image August McLaughlin
August McLaughlin is a certified nutritionist and health writer with more than nine years of professional experience. Her work has been featured in various magazines such as "Healthy Aging," "CitySmart," "IAmThatGirl" and "ULM." She holds specializations in eating disorders, healthy weight management and sports nutrition. She is currently completing her second cookbook and Weight Limit—a series of body image/nutrition-related PSAs.

When a sudden digestive illness has you clutching your stomach, and you are up against vomiting, diarrhea or both, it's natural to wonder whether it's a stomach flu or food poisoning. Stomach flu and food poisoning can produce similar symptoms, but have different causes and different ways of spreading. Learning the differences between stomach flu and food poisoning can help you know when it's important to seek medical care, and aid you in preventing future illness by taking the right kinds of precautions.

What Causes Stomach Flu

The illness many people call “stomach flu” isn't one illness, but rather refers to several viruses that can cause gastrointestinal symptoms such as cramping, vomiting, and diarrhea. Stomach flu outbreaks in communities may be caused by noroviruses, rotavirus, astrovirus or adenovirus. Symptoms of a stomach virus may appear 1 or 2 days after you're exposed and last for up to 5 days.

What Causes Food Poisoning

Food poisoning refers to getting sick after eating food tainted by certain bacteria. Symptoms may be similar to stomach flu, and may include fever, cramping, diarrhea, or vomiting. Symptoms may appear within a few hours after eating contaminated food, and usually within 48 hours.

Some common types of bacteria that cause food poisoning include: Salmonella, often associated with eggs, poultry, and unpasteurized dairy products; E. coli, often associated with undercooked beef, unpasteurized milk, and raw fruits or vegetables; Clostridium perfringens, often associated with foods like casseroles not kept at the proper temperature; Listeria, often associated with dairy products and deli meats; Shigella, often associated with fecal contamination in raw vegetables, salads, and sandwiches; and Staphylococcus aureus, associated with improperly refrigerated meats and deli salads.

How You Catch Stomach Flu

Another key difference is in how you get each type of illness. Stomach flu, also called viral gastroenteritis, may be spread through food that was touched or prepared by someone who is sick, but food isn't the only source. Stomach flu can be spread person to person when you come into contact with bodily fluids such as saliva, vomit, or feces. You also can catch stomach flu by touching a surface that is contaminated with the virus, such as a door knob.

How You Get Food Poisoning

By comparison, you only get food poisoning by eating contaminated food. Typically, food poisoning stems from bacteria in food. Food can become contaminated when improper storage allows bacteria to grow, such as letting potato salad sit out instead of being refrigerated. Food can become contaminated with fecal bacteria when people who handle food fail to wash their hands after using the restroom. You also may get food poisoning when food isn't properly washed, processed, or cooked before it's served.

Preventing Stomach Flu

Because stomach flu and food poisoning have different causes, they also can have different means of prevention. The key to preventing the transmission of stomach flu is good hygiene. Frequent hand-washing after using the restroom, before preparing food, or before eating can help you avoid getting sick from noroviruses and other forms of viral gastroenteritis.

Preventing Food Poisoning

The key to preventing food poisoning lies in how you prepare and store food, as well as good hygiene practices. It's important to ensure that you wash your hands with soap before cooking, serving, or eating food; you wash raw fruits and vegetables before you eat them; you cook meat to a proper temperature to kill bacteria and keep it hot until served; you properly seal and store leftovers; and you keep cooking surfaces and equipment clean.

When to See a Doctor

Stomach viruses and bacterial food poisoning can cause serious illnesses. When you can't keep food or liquids in your body because of vomiting or diarrhea, you may become dehydrated. If left untreated, dehydration can be life-threatening. If your vomiting or diarrhea continues after several days, you should see a doctor. If you see blood in your stool, that's also a warning sign to get medical help.

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