Listeria outbreak tied to sliced deli meat hospitalizes 57, kills 9

All told 57 people have been hospitalized and nine people have died across 18 states in the current outbreak. The six new deaths occurred in Florida, Tennessee, New Mexico, New York and South Carolina.

This is the largest outbreak of listeriosis since the 2011 outbreak linked to the consumption of contaminated cantaloupe, which sickened 146 people and killed 30.

Related: Ice cream cups sold in 20 states linked to Listeria outbreak, CDC warns

The current outbreak is tied to deli meat products from Boar's Head, including the Strassburger Brand Liverwurst. Products sold at the deli may be contaminated with the bacteria. Boar's Head has recalled many of its deli products, including the Strassburger Brand Liverwurst. In a statement released July 25, the company said that they "deeply regret the impact this recall has had on affected families."

Listeriosis is caused by the bacterium Listeria monocytogenes. Mild cases of listeriosis may include fever, muscle aches and nausea, while more severe forms can cause headaches, stiff neck, confusion and loss of balance. Listeria is particularly dangerous in pregnancy, as it can increase the risk of miscarriage, stillbirth and premature delivery. In some people, symptoms can take up to 10 weeks to develop. Severe disease usually starts to develop around one to four weeks after eating contaminated food.

Milder cases of listeriosis normally resolve on their own, however, more serious infections usually have to be treated with antibiotics.

Each year, the CDC estimates that around 1,600 people in the U.S. are infected with Listeria, and 260 of them die.

People should not eat the recalled deli meats.

"Everyone should check their homes for any remaining recalled Boar's Head products since they can have a long shelf-life," the agency noted in the statement. More generally, people should avoid eating meats sliced at deli counters, unless they are heated to an internal temperature of 165 degrees Fahrenheit (74 degrees Celsius), or are "steaming hot" before being served, the CDC advises.

This is especially important for those who are at a higher risk of getting sick, such as pregnant people, individuals aged over 65 and those with weakened immune systems.

L. monocytogenes is normally found in natural environments, such as soil and groundwater. However, if it gets into food, it can easily spread to humans and cause listeriosis. It can also linger on kitchen surfaces and deli equipment and can survive at refrigerator temperatures, according to the CDC. Some of the most common types of contaminated food include hot dogs, deli meats and fresh vegetables.

This article is for informational purposes only and is not meant to offer medical advice.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!