Food poisoning is either bacterial or viral. There are multiple variations of each type, however, the most common are:

Bacillus cereus
A type of bacteria commonly found in meats, rice and seafood products. Symptoms generally last for 24 hours and are a result of consuming foods that have had inadequate refrigeration or are not cooked to the correct temperature. You may begin to feel unwell in as little as a few hours after consuming the contaminated food or drink. Unlike many other types of food poisoning, diarrhea is not usually a common symptom.

E-Coli
A very common form of food poisoning found in the intestines of both animals and humans. E-coli forms a healthy part of the gut, but some strains can be harmful to your health. Symptoms can last up to 10 days, and E-Coli is highly contagious if the infected person does not take precautions to thoroughly wash their hands after use of the toilet or before preparing food. Animals can also carry E-Coli and transmit to humans. It’s common to also be infected by E-Coli from drinking contaminated water or even swimming in contaminated water. More severe cases of E-Coli infection can lead to kidney failure or blood in the stools.

Listeria
A serious strain of bacteria that can be life-threatening in particular people, including the elderly, pregnant women and young babies. It is one of the rarer forms of food poisoning, with 1,600 Americans suffering from listeria each year. Around 260 deaths are attributed to listeria per annum. Quite surprisingly, symptoms may take over two months to first appear. If a pregnant woman eats food that contains listeria, it is possible for her to pass listeria to her baby, which may lead to miscarriage or stillbirth. Left untreated, listeria can lead to complications such as brain damage, heart complications, and septicemia.

Salmonella
One of the most common causes of food poisoning, salmonella is often carried through undercooked food, cross-contamination, or by contaminated water. Much like E-Coli, salmonella exists in the intestines of animals and humans, which in dairy and meat products can cause infection through contact with feces. Commonly infected foods are raw eggs, poultry, meat, and seafood. Even fruit and vegetables may carry salmonella by coming into contact with contaminated water.

Viral

Rotavirus
Most commonly affects children under the age of two years old. In fact, by the age of five, almost every child would have contracted rotavirus. Rotavirus can not only be spread by contaminated food, but also by coming into contact with contaminated objects or people. This is why outbreaks are common in child care centers or public playgrounds. An immunity is built up from the first contraction of rotavirus as a baby or child and continues to build upon each subsequent contraction. For this reason, rotavirus is uncommon in adults.

Hepatitis A
First symptoms of hepatitis A do not appear until around a month after infection. The duration of symptoms also ranges for a lengthy period of time of between two months and anywhere up to six months. Hepatitis A is a unique version of food poisoning in that it directly affects the liver, resulting in a common symptom of jaundice, which is the yellowing of the skin. Hepatitis A is common in third-world countries, and a vaccine is highly effective in its prevention.

Norovirus
This is the most common form of food poisoning in contaminated food within the US. Each year, up to 23 million cases of gastroenteritis in the US are due to norovirus. Humans are the only carriers of norovirus. It acts similar to the flu, having the ability to cause major outbreaks as it is highly contagious. To put things into perspective, it is thought that nearly 60% of all foodborne illnesses are caused by norovirus.