Foster Farms chicken has been pinpointed as the cause of an 18-state salmonella outbreak that has made hundreds sick in recent months. 

According to the Associated Press, a public alert has been issued for raw chicken packaged at three Foster Farms facilities in California. The outbreak has sickened 278 people with strains of Salmonella Heidelberg which was first detected in March. Salmonella Heidelberg was found in the chicken distributed at retail outlets in California, Oregon and Washington, the United States Department of Agriculture announced. 

Dan Engeljohn of the USDA's Food Safety and Inspection said the agency was notified of the illnesses in July, but investigators had a difficult time pinpointing the source. 

The infections were caused by people eating chicken which was undercooked or improperly handled. Chicken should be cooked to 165 degrees. There has been no recalled issued on the California facilities located in Central Valley's Livingston and Fresno.

"This is the important public health issue," Anita Gore, spokeswoman for the California Department of Public Health. "Chicken can carry bacteria, and chicken needs to be fully cooked."

Foster Farms issued a statement apologizing for the outbreak and ensuring their customers that they are working hard with health officials. 

"Food safety is - and always has been - at the very heart of our family business. On behalf of my family, I am sorry for any foodborne illness associated with Foster Farms chicken and for any concern this may have caused you," the statement read. "All of us at Foster Farms are continuing to work around the clock to fully address this situation and to ensure you have a safe and wholesome experience with our products."

Despite debate on a specific product or production period, the USDA stated the suspect packages would read: P6137, P6137A and P7632. Salmonella is a pathogen that contaminates meat during slaughter and processing, and is especially common in undercooked chicken.

Gore also said people need to thoroughly wash their hands after handling raw meat, and anyone who believes they were infected and are showing symptoms like diarrhea and abdominal cramps should contact doctors immediately.