Salmonella Outbreak Worse than Expected

ANALYSIS - A virulent outbreak of salmonella poisoning in the US, which has now made 179 people ill, has led to a multi-state investigation into its cause and a major effort to ensure products are recalled and communities kept safe, writes Chris Harris

28 November 2011

4 minute read

By: Chris Harris

North America

The Centers for Disease Control in the US is collaborating with public health and agriculture officials in New York, New Jersey, other states, the US Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), and the US Food and Drug Administration to investigate the outbreak of Salmonella Heidelberg infections.

Epidemiologic and laboratory investigations conducted by officials in local, state, and federal public health, agriculture, and regulatory agencies linked this outbreak to eating “kosher broiled chicken livers” from Schreiber Processing Corporation (doing business as Alle Processing Corporation/MealMart Company), and chopped chicken liver prepared from this product.

These “kosher broiled chicken livers” have been sold at retail stores and may be used as an ingredient in other prepared foods.

These products appear to be ready-to-eat, but are in fact partially cooked, and therefore need to be fully cooked before eating.

The CDC has been concerned that consumers may have incorrectly thought the use of the word “broiled” in the label meant the chicken liver was ready-to-eat; however, these chicken livers must be fully cooked before eating.

The CDC says that Alle Processing Corporation/MealMart Company is cooperating in the on-going investigation.

The CDC said that public health investigators are using DNA “fingerprints” of Salmonella bacteria obtained through diagnostic testing with pulsed-field gel electrophoresis (PFGE) to identify cases of illness that may be part of this outbreak.

They are using data from PulseNet, the national subtyping network made up of state and local public health laboratories and federal food regulatory laboratories that performs molecular surveillance of foodborne infections.

One of the problems the CDC and the health investigators are finding is that the Salmonella Heidelberg PFGE pattern associated with the outbreak commonly occurs in the United States and some of the cases they are finding with the pattern may not be related to the current outbreak.

The health investigators say that past experience and examination of all the data shows that thewy expect between 30 and 40 cases to be reported each month as the outbreak progresses.

The inspectors are keen to point out that this outbreak strain is different from another strain of Salmonella Heidelberg associated with ground turkey recalled earlier this year.

The CDC identified a sustained increase in the number of Salmonella Heidelberg isolates with the outbreak strain reported to PulseNet from New York and New Jersey in August.

Based on the previous five years of reports to PulseNet, New York and New Jersey were expecting approximately five cases per month, but from June to August, these states were finding approximately 30-40 cases a month.

No sustained increase in the number of illnesses above baseline has been identified in other states.

The USDA-FSIS investigation found the “kosher broiled chicken livers” were distributed to New York, New Jersey, Pennsylvania, Maryland, Minnesota, Ohio, Rhode Island, and Florida and as the investigation continues it is believed that other states may be identified.

From 1 April to 16 November 16 a total of 179 illnesses due to Salmonella Heidelberg with this PFGE pattern were reported in states where the “kosher broiled chicken livers” were distributed. The number of ill persons identified in each state was New York (99), New Jersey (61), Pennsylvania (10), Maryland (6), Ohio (2), and Minnesota (1). Rhode Island and Florida have not identified any cases linked to this outbreak during this period.

Among 37 ill persons for whom information is available, 25 (68 per cent) reported consuming chicken liver products in the week before their illness began.

Laboratory testing conducted by the New York State Department of Agriculture and Markets Laboratory Division identified the outbreak strain of Salmonella Heidelberg in samples of “kosher broiled chicken livers” and chopped liver products obtained from retail stores.