This photo from the Centers for Disease Control and Prevention shows some of the most common types of bacteria that occasionally get into the food we eat and can make people sick. From top to bottom are campylobacter, salmonella, E. coli 0157:H7, norovirus and staphylococcus aureus.

Some gross things are fun. But some gross things should be avoided.

There have been a few outbreaks recently in which unwanted germs have ended up in food and made a lot of people ill. In severe cases of food poisoning, people can die. Food companies and the government make a big effort to keep these microscopic troublemakers out of our food supply. Most of the time those food safety measures keep our meat, fruit and vegetables clean and healthful. But mistakes can happen, and when they do, food can get infected.

Most of the bacteria found in food-poisoning cases come from animal waste (poop). These germs don’t make the animal sick but are harmful to people, typically causing severe diarrhea and maybe vomiting. Sometimes these dangerous germs can get onto meat when cows, pigs and chickens are turned into the food we eat. Animal waste also can get on fruits and vegetables grown on farms because animals live on farms, too.

Bacteria can be seen with powerful microscopes, but not with the naked eye. That’s why it’s important to understand where these bacteria can live and how dangerous they are. If you understand that these germs can make you sick, you will understand why it’s so important to take a few basic steps to keep your food safe – including cooking it thoroughly and always washing your hands. KidsPost introduces you to some of the germs you don’t want in your meal.

Campylobacter (CAMP-ee-loh-BACK-ter)

From animal waste. Can infect meat or produce, inside the food or on the surface. Sometimes found in the water sprayed on food. Takes only a small amount to make a person very sick.

Salmonella (sal-moh-NEL-uh)

Also from animal waste. Can be in meat, poultry, milk or eggs, and sometimes on produce. Takes a larger amount to make a person sick.

E. coli 0157:H7 (ee-KOH-lye)

Very dangerous bacteria, also from animal waste. Can be deadly, in part because the bacteria produce a poison that makes the infection harder to treat. Found recently on spinach that had been sprayed with infected water, making dozens of people sick nationwide.

Norovirus (NOR-oh-VYE-russ)

A virus found in water or on surfaces. Causes severe vomiting. Outbreaks have happened on cruise ships, in hospitals and nursing homes, and even among fans at sporting events. Often requires medical care.

Staphylococcus aureus (staff-i-loh-KOK-uss OR-ee-uss)

In food that is left unrefrigerated or handled incorrectly, these bacteria grow and make a poison. That toxin causes severe vomiting a few hours later, lasting 12 to 24 hours.