With two more deaths being reported from Lousiana, the listeria outbreak has become the deadliest epidemic in the United States in last 25 years.

Deaths from the largest U.S. food-borne listeria previously claimed lives in Colorado, Indiana, Kansas, Maryland, Missouri, Nebraska, New Mexico, New York, Oklahoma, Texas and Wyoming.

With the recent deaths, the death toll in listeria outbreak has reached 23 across 12 states, health officials said.

According to the Centers for Disease Control and Prevention, 116 people have been affected by the outbreak.

A listeria outbreak in 1998 killed 21 people.

Investigators traced the outbreak to cantaloupes grown at Jensen Farms in Granada, Colo., following the finding of listeria monocytogenes in a sample from there. The Food and Drug Administration has advised consumers to throw out the recalled melons.

Contaminated cantaloupes are believed to have been shipped to Arkansas, ArizonaCalifornia, Colorado, Idaho, Illinois, Kansas, Minnesota, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Virginia and Wyoming.

Listeria is a dangerous bacteria that flourishes in cool temperatures and is particularly dangerous to the elderly or to people with weakened immune systems. There are about 800 reported cases a year in the United States, most of them linked to meat and soft cheese.

Listeria can grow in refrigerators or at room temperature, unlike other pathogens, and has an incubation period of about a month. The ease with which it can spread is leading officials to predict more canteloupe cases before the outbreak is over.