Salmonella Recalls: What Are Poisoning Symptoms and How Does Food Get Contaminated?

In the latest health scare linked to salmonella, the makers of Goldfish Crackers have recalled 3.3 million packs of their products amid fears the snacks could be contaminated with bacteria.

So what is salmonella, why is it so dangerous, and how does it get into food?

Salmonella is the name given to around 2,000 types of bacteria that can trigger abdominal cramps, diarrhea and fever, which lasts between four to seven days.

Sufferers can also experience headache and muscle pains. These symptoms will usually appear between six to 72 hours after the bacteria is ingested.

The makers of Goldfish have recalled the snacks amid a salmonella scare. Getty Images

Each year in the U.S., salmonella makes around 1.2 million people sick, causing 23,000 hospitalizations and killing around 450 people.

As most cases of salmonella aren't treatable with antibiotics, those with the infection must simply let their immune system fight it off while drinking plenty of fluids to prevent dehydration.

However, if a person's diarrhea is severe, they may need to be treated in hospital for dehydration. In rare cases, the bacteria can spread into the bloodstream which, if left untreated, can result in death. Those with weak immune systems, such as children under the age of five and the elderly, are most at risk of serious complications.

Sometimes, a person will be infected with salmonella yet not experience any symptoms. However, they will still be able to pass it on in their feces. That's why following hygiene practices like washing your hands after using the restroom and before preparing food is so important.

Salmonella generally lives in the intestinal tracts of humans and animals, and food usually becomes contaminated when it comes into contact with infected fecal bacteria. It usually affects animal products—like meat, dairy and eggs—but anything from fruit to cereal can carry the bacteria. And as the bacteria are microscopic, food will appear normal and a person will only know it is contaminated when it's too late.

In the cases of the Goldfish Crackers and the recent Mondelez recall of Ritz crackers and Ritz Bits, whey powder used to flavor the products was believed to be contaminated with salmonella.

Similarly, Kellogg's recalled Honey Smacks cereal after it was associated with a salmonella outbreak hitting 100 people across 33 states. The ingredient which caused it was being investigated.

At the time, the Centers for Disease Control and Prevention warned consumers not to eat the cereal.

"Do not eat any Kellogg's Honey Smacks cereal, regardless of package size or best-by date. Check your home for it and throw it away, or return it to the place of purchase for a refund," the CDC said.