Editor's note: The numbers in this story were revised on Apr 15 to reflect a correction issued by the Food and Drug Administration. The FDA originally said the outbreak involved 23 cases in 14 states, but on Apr 15 the agency said the correct numbers were 21 cases in 13 states.
Apr 14, 2008 (CIDRAP News) – The US Food and Drug Administration (FDA) has linked at least 21 illnesses in 13 states to a Salmonella strain that triggered a recent recall of puffed rice and puffed wheat cereals made by Malt-O-Meal, based in Minneapolis.
According to federal and state public health officials, the outbreak involves the same uncommon strain, Salmonella enterica serotype Agona, that caused an outbreak 10 years ago that was linked to toasted oats cereal produced at Malt-O-Meal's Northfield, Minn., plant.
The FDA, in an Apr 12 statement, said the products—originally recalled on Apr 5—include unsweetened puffed rice and puffed wheat cereals that were distributed nationally under the Malt-O-Meal label, as well as several other private-label brands such as Acme, America's Choice, Food Club, Giant, Hannaford, Jewell, Laura Lynn, Pathmark, Shaw's, ShopRite, Tops, and Weis Quality. The products have "best if used by" dates that range from Apr 8, 2008, to Mar 18, 2009.
Malt-O-Meal said in an Apr 11 press release that routine sampling revealed Salmonella on a product that was produced on Mar 24, and a follow-up investigation determined additional products may have been exposed to the pathogen.
In a statement issued Apr 11, the US Centers for Disease Control and Prevention (CDC) said the Minnesota Department of Health had confirmed that an S Agona isolate obtained from the state's Malt-O-Meal plant had the same pulsed-field gel electrophoresis (PFGE) pattern as isolates from people who were ill.
According to the CDC's most recent count, as of Apr 11 the outbreak had sickened 21 patients in 13 states, including California, Colorado, Delaware, Maine, Massachusetts, Pennsylvania, Rhode Island, and Vermont. Illness onset dates were known for 9 patients and ranged from Jan 22 to Mar 2. Patients' ages range from 1 to 95 years, and 62% are female. Three hospitalizations have been reported, but no deaths.
The CDC said the PulseNet system notified its outbreak team on Apr 7 about a cluster of human S Agona isolates from several states that had the same genetic fingerprint. Three days later, several state health departments notified the CDC that patients who had S Agona infections had eaten Malt-O-Meal cereal products.
State health departments, the CDC, and the FDA are in the process of identifying additional cases and are investigating what led to the outbreak, according to the CDC statement. However, Malt-O-Meal said its own investigation into the source of the Salmonella had "determined a root cause of this situation and corrective measures have been taken to ensure that there is no reoccurrence of this issue." The company did not specify what the root cause was.
Chris Neugent, Malt-O-Meal's president and chief executive officer, said in the press release that the company has had a strong food safety record with systems that exceed industry standards, including a new program that requires suppliers to use third-party audits to prove they have effective food safety programs.
"We will take any additional measures necessary to preserve our customers' confidence in the safety and wholesomeness of the products we offer to consumers," he said.
In April and May of 1998, at least 209 people from 11 states were sickened in an S Agona outbreak involving Malt-O-Meal's toasted oats cereal, according to a Jun 12, 1998, report in Morbidity and Mortality Weekly Report (MMWR). At least 47 patients were hospitalized. According to the MMWR report, the outbreak only involved the Millville brand of toasted-oats cereal made by Malt-O-Meal.
In the MMWR report, the CDC said S Agona is an uncommon serotype that accounts for about 1.5% of human Salmonella isolates and is found in several animal reservoirs, including poultry, cattle, and pigs, and in animal feed. Other outbreaks involving S Agona have been linked to dried milk and a commercial peanut-flavored snack.
Craig Hedberg, PhD, a foodborne disease expert and associate professor of environmental health sciences at the University of Minnesota School of Public Health in Minneapolis, told CIDRAP News that there may an environmental source of S Agona at the plant, despite the steps that Malt-O-Meal reportedly took in response to the previous outbreak in 1998.
"My guess is that the bug may have been in the plant the whole time, but that to have enough contamination to cause an outbreak also required an amplifying event," he said.
Hedberg said that if this is, in fact, the same strain that caused the previous outbreak, it would be interesting to review PulseNet data see if health officials have missed other cases involving the outbreak strain over the past 10 years.
This latest Salmonella outbreak underlines a finding the CDC released a few days ago in its annual FoodNet update, he said. "We haven't made much progress in controlling Salmonella," Hedberg said. Data from the CDC's 10-state FoodNet surveillance system suggested that in 2007 rates of infection with Campylobacter, Listeria, Salmonella, Shigella, E coli O157, and Yersinia did not decline significantly compared with the previous 3 years.
Of 17,883 foodborne infections that were reported through FoodNet in 2007, up slightly from the 17,252 reported in 2006, Salmonella led the list, with 6,790 confirmed cases (38% of the total).
Apr 12 FDA press release
CDC Salmonella Agona page
CDC. Multistate outbreak of Salmonella serotype Agona infections linked to toasted oats cereal—United States, April-May, 1998. MMWR 1998 Jun 12;47(22):462-4 [Full text]
Apr 10 CIDRAP News story "Foodborne disease rates changed little in 2007"