Salmonella continues to spread across the United States. Despite this, The Department of Agriculture said it will not close chicken-processing plants connected to a recent outbreak.

"Foster Farms has submitted and implemented immediate substantive changes to their slaughter and processing to allow for continued operations," Aaron Lavallee, USDA spokesman, told USA Today.

Inspectors from the USDA Food Safety Inspection Service will ensure that changes are made to the three plants on "a continuous and ongoing basis," according to Lavallee. Lavallee also said that the inspectors will perform "intensified sampling for at least the next 90 days."

According to Keith Dailey, a Foster Farms spokesman, the company removed its products from the infected plants.

Salmonella is not uncommon in chicken. USDA performance standards allow up to 7.5 percent of chicken carcasses in a plant to test positive for the bacteria. The variety of salmonella is what becomes a risk.

42 percent of the people infected by Foster Farms chicken have been hospitalized, which is about twice the normal rate, according to the Centers for Disease Control and Prevention (CDC).

Here is a breakdown of salmonella outbreaks in 2013 based on data from the CDC.

Multidrug-Resistant Salmonella Heidelberg Infections Linked to Foster Farms Brand Chicken

  • 278 infected from 17 states

  • 77 percent of illness from California

Salmonella Montevideo and Salmonella Mbandaka Infections Linked to Krinos Tahini Sesame Paste

  • 16 infected from 9 states

  • California (1), Georgia (1), Iowa (1), Louisiana (1), Minnesota (2), New York (1), North Dakota (1), Texas (7), Wisconsin (1)

  • 1 hospitalized, 1 dead

Salmonella Typhimurium Infections Linked to Live Poultry in Backyard Flocks

  • 316 infected from 37 states
  • 26 percent infected hospitalized

Salmonella Infections Linked to Live Poultry

  • 125 infected from 26 states
  • ·Alabama (3), Arizona (3), California (1), Colorado (2), Connecticut (3), Delaware (1), Georgia (1), Illinois (4), Indiana (1), Kentucky (4), Maine (1), Maryland (1), Massachusetts (7), Minnesota (3), Mississippi (2), Nebraska (1), New Jersey (2), New York (10), North Carolina (10), Ohio (19), Pennsylvania (8), Tennessee (12), Vermont (2), Virginia (3), West Virginia (15), Wisconsin (6)
  • 29 percent infected hospitalized, 0 dead

Salmonella Saintpaul Infections Linked to Imported Cucumbers

  • 84 infected from 18 states
  • 28 percent infected hospitalized, 0 deaths

Salmonella Heidelberg Infections Linked to Chicken

  • 134 infected from 13 states
  • Oregon (40), Washington (57)
  • 31 percent infected hospitalized, 0 deaths

Salmonella Typhimurium Infections Linked to Ground Beef

  • 22 infected from 6 states
  • Arizona (1), Illinois (2), Iowa (1), Michigan (9), Pennsylvania (1), Wisconsin (8)
  • 50 percent infected hospitalized, 0 deaths

Salmonella poisoning symtoms include fever, cramps and diarrhea, which ususally begin eight to 72 hours after ingesting food with high amounts of the bacteria. Vomiting, nasusea and chills can last up to seven days. Treatment is done with prescribed antibiotics.