How long does it take for food poisoning to take effect?

When food is prepared improperly, it can contain harmful organisms that cause considerable distress to the human body. Food poisoning can arise from the harvesting and processing of ingredients, from the way they are stored or from improper preparation--especially if the food is served raw. Symptoms of food poisoning include nausea, diarrhoea, stomach cramps, fever and physical weakness. They begin to appear anywhere from several hours to several days after the food is ingested.


The earliest onset of food poisoning occurs with listeria (found in unpasteurised dairy products, lunch meats, hot dogs and produce), noroviruses (found in shellfish and raw produce), Clostridium perfringens (found in gravy and undercooked stew) and Staphylococcus aureus (found in meat and cream). They can appear anywhere from 1 to 48 hours after contact.


Some contaminants take a few days to act on the body before symptoms appear. The best-known is Salmonella, which can be found in meat, chicken products and milk; food poisoning symptoms appear one to three days after being consumed. Rotavirus and shigella, both found in raw produce, have a similar timetable. Campylobacter, found in meat and poultry that has come into contact with fecal matter, manifests after two to five days. E. coli virus, found in contaminated beef and unpasteurised milk, takes one to eight days before manifesting symptoms. Vibrio vulnificus--found in shellfish such as mussels and oysters--also appears within one to seven days.


In some cases, food poisoning may take weeks before symptoms start to appear. Hepatitis A, for example, doesn't appear for almost four weeks; it can be found in shellfish, produce and similar raw foods. Giardia lamblia, which appears in raw vegetables, manifests after 7 to 14 days. These origins of food poisoning can be difficult to pinpoint sometimes because of the length of time between eating the food and exhibiting the symptoms.


Once food poisoning manifests, it can last from a day to a week and a half. The biggest danger during this period is dehydration from loss of fluids (vomiting and diarrhoea dry you out quickly). You may have a hard time keeping food down. Try to drink as much water as you can, or suck on ice cubes if you have problems swallowing. Eat bland, easy- to-digest foods such as crackers and broth when you can in order to keep your strengthen up. In instances when you can't swallow liquid for more than 24 hours, contact a doctor immediately. He can arrange for an IV drip or similar means of hydration to keep you stable until the food poisoning runs its course.


Because food poisoning can be delayed significantly, it's important to recall just what you ate over a given time period. Look for raw foods such as oysters and salad or places you may have eaten that didn't look up to code. If you can recall when you ate there and what foods you consumed, you can create a basic timetable to determine what kind of food poisoning is involved.

Most recent