Is Food Poisoning Contagious?
Food Poisoning & Stomach Flu: Similar, But Still Different Beasts
There’s a large misunderstanding about food poisoning that needs to be addressed right off the top: food poisoning and the stomach flu are different beasts. Stomach flu, which is normally a gastrointestinal illness known as norovirus, is also called the stomach virus, winter virus, winter vomiting bug, and other names. The stomach flu and food poisoning are thought to be one and the same because they have very similar symptoms, but they are in fact distinct.
The best way to know whether you’ve got food poisoning or stomach flu is by working backward from the time you start showing symptoms. If it’s less than 6 hours since you ate a questionable meal (perhaps a meal at a restaurant, or one with fish or other undercooked meats), it’s most likely food poisoning. If it’s more than 12 hours since a questionable meal, or you’re quite certain that you haven’t become sick from food, then it’s most likely stomach flu.
Let’s look at how else the two differ.
Is food poisoning contagious? No.
| FOOD POISONING | STOMACH FLU | |
|---|---|---|
| CAUSES | Contaminated foods | Contaminated foods or surfaces contaminated from another person with stomach flu |
| IS IT CONTAGIOUS? | NO | YES, under very particular circumstances. You are contagious from the time you start showing symptoms to 48-72 hours after symptoms disappear. More info below. |
| HOW DOES IT SPREAD? | Only through contaminated food | Particles from diarrhea or vomit enter through the mouth (fecal-oral transmission). Mouth closed = 100% safe. |
| SYMPTOMS | Diarrhea Fever Vomiting Nausea Severe stomach cramps Fatigue Headache | |
| HOW LONG UNTIL SYMPTOMS APPEAR? | 1 – 6 hours | 12 – 48 hours |
| HOW LONG DO SYMPTOMS LAST? | 24-48 hours Full timeline below. | 24-72 hours Full timeline below. |
| PREVENTION TECHNIQUES SEE BELOW | #2 CLEAN FOODS #4 CLEAN HANDS | #1 CLEAN AIR #2 CLEAN FOODS #3 CLEAN SURFACES #4 CLEAN HANDS |
| TREATMENT | Stay hydrated with water and/or Gatorade, and slowly introduce bland foods like cereals, breads, fruits and vegetables into your diet as you feel ready. | |
| WHEN SHOULD YOU SEEK MEDICAL TREATMENT? | If symptoms are excessive to the point of not being able to maintain any liquids, or if symptoms persist for longer than 72 hours. | |
If you never open your mouth, you’re 100% safe!
Food poisoning spreads only through food, so if you don’t open your mouth to eat, you can’t get food poisoning. It’s really as simple as that.
And the stomach flu is an enteric virus, which means it’s spread through “the fecal-oral route”. In other words, you need to swallow virus particles originating from either a patient’s feces or vomit in order to become sick. Breathing these particles in through your nose doesn’t count; they must enter through the mouth in order to make it down to the small intestine, where the virus incubates. Therefore mouth closed = totally safe.
Of course, keeping your mouth closed 24/7 is not very practical, so here are the 4 best ways to stay healthy and safe from disease.
How to avoid getting food poisoning or stomach flu – The Big Four
Take these four precautions and you’ll be 99.9%+ safe from getting either food poisoning or the stomach flu.
#1 CLEAN AIR
This one is much simpler than you’d think, because unless someone is vomiting or experiencing diarrhea while you’re in the room (when the virus will be airborne), the air will be clean. Virus particles settle extremely quickly, so unless the act is happening before your eyes, you’re safe from airborne transmission. It’s impossible to get sick by breathing the same air as someone with food poisoning or the stomach flu.
One important precaution to take here is to always close the toilet lid before flushing so potentially viral particles aren’t thrust up and into the bathroom.
#2 CLEAN FOODS
Food is the only way to contract food poisoning (surprising, huh), and a major method that stomach flu spreads. There are 2 major ways to keep yourself safe here:
- Wash your fruits and vegetables thoroughly. Wash them in a similar way that you wash your hands (though without soap) to get rid of any possible bacteria or virus particles. Note that just like with washing your hands, you’re washing the particles away and down the drain, not killing them, so using hot water is no more effective than cold water.
- Be smart when you cook. As you can see in the list of high-risk foods below, there are some pretty delicious foods on that list. Does that mean you should eliminate them from your diet entirely? Absolutely not. Instead, just ensure that your meats and fish (including shellfish like oysters) are cooked thoroughly and that you aren’t consuming unpasteurized or questionable dairy. And there’s no need to be over-cautious with it: dairy products are still perfectly consumable for days or even weeks after their published expiry date, so unless you have a really strong feeling that something is amiss, you’re probably fine.
Oh, and just to be safe, never prepare food for others until at least 48 hours after all your symptoms have disappeared!
#3 CLEAN SURFACES
When cooking, sometimes we place high-risk foods like raw meats on the same dishes as cooked foods, or we use the same utensils to handle both. This is the easiest way to cross contaminate one food to another without knowing it, so always be sure to use separate dishes and utensils when dealing with high-risk foods.
It’s also important to thoroughly clean surfaces that a person with stomach flu may have come into contact with (these inanimate objects that carry viruses are called fomites), since touching a fomite and then touching your mouth is a very common way to catch the stomach flu.
Common fomites include:
- Everything in the bathroom (think toilet flushers, sinks, countertops, etc.)
- Door handles
- Bedding and clothing a sick person used or wore during the time they were sick
- Any items they handled while being sick
- If they vomited anywhere else but in the bathroom (such as in a bucket next to their bed), any object within a 3-foot radius of that point. (The 3-foot radius is important because stomach flu particles, which are released when a sick person defecates or vomits, travel up to 3 feet before settling on a surface.)
These virus particles can survive for 7 days or more if not cleaned effectively, so launder all bedding and clothing and clean all surfaces and objects using this bleach solution, which has been proven to be extremely effective in eliminating stomach flu particles.
Making your bleach cleaning solution: You want your bleach solution to be at a strength of 5,000 ppm chlorine. To do that, you’ll need to dilute your stock household bleach (normally 5.25% sodium hypochlorite at a concentration of 50,000 ppm chlorine) to 10% with water. Expressed as a ratio, that’s 9 parts water to 1 part bleach, or ¼ cup bleach to 2 ¼ cups water.
Using more bleach doesn’t help to kill the virus any better – it only wastes bleach, and makes your home more toxic than it needs to be.
#4 CLEAN HANDS
This is the biggest of them all! Keeping your hands clean is by far the best precaution you can take against getting sick, and it’s as simple as washing them with soap and water for a thorough 20 seconds. Remember that, just like we said above about fruits and vegetables, you’re washing the particles away and down the drain, not killing them, so using hot water is no more effective than cold water. Also, antibacterial hand sanitizers don’t kill the stomach flu virus (since it’s a virus and not a bacteria), so don’t take any shortcuts: just wash your hands with soap and water for 20 seconds multiple times per day, including after using the bathroom and before every meal, of course. Is that too much to ask for?
And don’t put your hands in/near your mouth!
I can’t stress this enough: You cannot catch the stomach flu simply by touching an infected surface. You need to put your hand in your mouth for it to spread, so washing your hands is the best way to stop the spread.
HOW LONG DOES FOOD POISONING LAST?
Food poisoning symptoms tend to be more severe and shorter-lived than those of the stomach flu. On average, food poisoning symptoms last 24-48 hours, while it’s not uncommon for stomach flu symptoms to last up to 72 hours.
Here’s a typical timeline for both food poisoning and stomach flu.
A Typical Timeline of Food Poisoning
Hour 0: You ingest the food poisoning bacteria from eating undercooked meat, unpasteurized dairy, unwashed fruits/vegetables, or contaminated fish or shellfish. It’s possible to contract it from other foods as well, but these four categories make up the vast majority of cases.
Hours 1-6: Symptoms begin to appear. Symptoms almost always include diarrhea and vomiting, and could also include a fever, nausea, stomach cramps, fatigue, and headaches. Prepare yourself: it’s going to be a miserable couple of days.
Hours 7-30: The food poisoning is at its maximum. You feel awful, but as long as you’re drinking water (and not expelling it via diarrhea or vomit immediately), you’re going to be okay. These first 24 hours are the roughest.
Hours 31-54: Symptoms may still be strong, or they may be disappearing – it’s different in every case. By the end of this period, though, from about 48 hours after you started showing symptoms, they should be significantly reduced or gone altogether
Hours 54 and Beyond: Symptoms are most likely gone at this point. If your symptoms haven’t subsided and you still feel like hell in a handbasket, consult a doctor for a personalized opinion.
A Typical Timeline of Stomach Flu
Hour 0: You swallow the stomach flu virus from contaminated food or by handling a contaminated surface and then touching your mouth.
Hours 12-48: Symptoms begin to appear. Just like with food poisoning, symptoms almost always include diarrhea and vomiting, and could also include a fever, nausea, stomach cramps, fatigue, and headaches. Prepare yourself: it’s going to be a miserable few days.
Hours 49-96: The stomach flu is at its maximum. You feel bad, but as long as you’re drinking water (and not expelling it via diarrhea or vomit immediately), you’re going to be okay. These first 48 hours are normally the roughest.
Hours 97-120: Symptoms may still be strong, or they may be disappearing – it’s different in every case. By the end of this period, though, from about 72 hours after you started showing symptoms, they should be significantly reduced or gone altogether
Hours 120 and Beyond: Symptoms are most likely gone at this point, though keep in mind that you’re still contagious for about 3 days after your symptoms disappear, so continue to be cautious and disinfect surfaces to ensure the virus disappears from your home completely. If your symptoms haven’t subsided and you still feel like hell in a handbasket, consult a doctor for a personalized opinion.
Food Poisoning Treatment 101: Stay Hydrated!
Despite the awful feeling of having food poisoning or the stomach flu, the biggest risk they pose to you is actually dehydration. That said, stay hydrated with water and/or Gatorade, and slowly reintroduce food into your diet as you feel comfortable.
If you are vomiting excessively and cannot keep any liquids in your system, get in touch with a medical doctor. Food poisoning and stomach flu pose a greater risk to children, the elderly, and terminally ill people, so if you fall into that category, get in touch with a doctor as soon as you begin exhibiting symptoms.
High-Risk Foods For Food Poisoning & Stomach Flu
- Raw or undercooked meat products
- Fish and shellfish
- Unpasteurized or expired dairy products (milk, cheese, cream, eggs)
- Vegetables and fruits that aren’t well-washed
Food Poisoning & Stomach Flu Myths
Myth: Foods that cause food poisoning look, taste or smell bad.
Truth: most foods that cause food poisoning look, smell and taste perfectly normal.
Myth: Food poisoning is a rare condition that happens when you travel overseas.
Truth: Food poisoning affects 1 in 6 Americans every year, and while it’s possible to contract food poisoning overseas, the vast majority of cases come at home from the mishandling of food.
Myth: Food poisoning is really dangerous.
Truth: While you’ll feel pretty crappy for a few days, both food poisoning and the stomach flu are largely harmless. The biggest risk they pose is dehydration, so always stay hydrated throughout.
It is impossible to contract food poisoning or the stomach flu in any of these ways:
- Being near or breathing the same air as someone who has it.
- Walking past a pool of vomit.
- Having sexual relations with an infected person.
- Having a cut in your skin.
- Sitting on a toilet seat, or catching it through your rectum or genitalia.
- Kissing someone who is not yet showing symptoms.
- Sharing cups or utensils with someone who has the virus but isn’t showing symptoms.
Summary: The big four ways to avoid getting sick from food poisoning or stomach flu
#1 CLEAN AIR
Stay out of the room when someone releases the particles (ie. when they’re defecating or vomiting).
#2 CLEAN FOODS
Wash your fruits and vegetables thoroughly, cook your meats fully, and don’t allow raw foods to cross contaminate cooked foods via dishes or utensils.
#3 CLEAN SURFACES
Any bedding/clothing used by someone with the stomach flu, plus any items and surfaces they were exposed to, should be cleaned with a bleach solution.
#4 CLEAN HANDS
This is the most important action you can take. These illnesses only spread through your mouth, so if your food is clean and you keep your hands clean (in case you touch your mouth), you’re 100% safe.
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