The Centers for Disease Control and Prevention this week warned distributors against selling hard-boiled eggs bought in bulk from a Georgia production plant that it said was the likely source of listeria contamination that had led to sicknesses in five states, including one death and four hospitalizations.
Officials with the federal Food and Drug Administration discovered the strain during a routine inspection in February at Almark Foods in Gainesville, Ga. The C.D.C. determined that the strain was the same one that caused three infections in 2017.
By this month, the strain had been found in at least five states — Florida, Maine, Pennsylvania, South Carolina and Texas — and in four more people, the C.D.C. said in a safety alert that it issued on Wednesday.
Five of the seven people infected were male and the median age was 75, according to the federal agency. One illness was reported in a newborn who was infected while the mother was pregnant; the infant survived.
The C.D.C. warned that the bulk, hard-boiled eggs packaged in plastic pails and sold to distributors were most likely contaminated. These eggs have a 49-day shelf life. Other goods, including hard-boiled eggs sold directly to consumers and products made with hard-boiled eggs, were not at risk, the agency said.
The production plant immediately stopped production this week after it heard from the F.D.A., Gene Grabowski, a spokesman for Almark Foods, said in an interview on Thursday. The company is working to sterilize the plant, which processes about 1.2 million eggs a day, before another federal inspection, he said, noting that he did not know when it would reopen.
Almark Foods has another plant in North Carolina, which remains in operation.
“No products have been recalled,” Mr. Grabowski said. “The F.D.A. found listeria on the exterior of the pails holding the products, but at no point were the eggs themselves considered to be compromised at the plant.”
From Feb. 5 to 8, the Food and Drug Administration conducted a routine inspection of the production plant, Mr. Grabowski said.
The regulatory agency collected 105 swab samples from the plant, Almark Foods said. Two of the swabs tested positive for listeria, prompting the agency to issue a warning letter to Almark on July 22, according to the F.D.A. The listeria contamination was found on a floor drain and at the end of a conveyor belt, which came into contact with food, according to the letter.
Almark Foods responded in a letter on Aug. 6, saying that it had “implemented a number of corrective actions” from March to June, like starting a new drain cleaning and sanitation program, replacing an old sump and installing a pallet washer.
But when reports of listeria cropped up in August, September and November, the C.D.C. linked the outbreak strain to the strain that had been found in the hard-boiled egg production plant. The agency also linked this strain to the three reports of listeria infection from 2017.
Similar to other food-borne germs, listeria can cause fever and diarrhea. People who are infected typically report symptoms one to four weeks after eating contaminated food, according to the C.D.C.
About 1,600 people get listeriosis each year, and about 260 die, according to the agency. Pregnant women, their newborns, adults older than 65 and people with weakened immune systems are most susceptible to infection.