Multistate Outbreak of Human Salmonella Montevideo Infections
Posted February 24, 2010
This outbreak appears to be over. However, Salmonella is an important cause of human illness in the United States. More information about Salmonella, and steps people can take to reduce their risk of infection, can be found on the CDC Salmonella Web Page.
Persons Infected with the Outbreak Strain of Salmonella Montevideo, United States, by State
Infections with the Outbreak Strain of Salmonella Montevideo, by Date of Illness Onset
CDC is collaborating with public health officials in many states, the U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS), the U.S. Food and Drug Administration (FDA), and the State of Rhode Island to investigate a multistate outbreak of Salmonella serotype Montevideo infections. Investigators are using DNA analysis of Salmonella bacteria obtained through diagnostic testing to identify cases of illness that may be part of this outbreak.
As of 9:00 pm EST on February 23, 2010, a total of 238 individuals infected with the outbreak strain of Salmonella Montevideo, which displays either of two closely related pulsed-field gel electrophoresis (PFGE) patterns, have been reported from 44 states and District of Columbia since July 1, 2009. The number of ill persons identified in each state with this strain is as follows: AK (1), AL (2), AZ (7), CA (30), CO (5), CT (5), DC (1), DE (3), FL (3), GA (3), IA (1), ID (4), IL (17), IN (4), KS (4), LA (1), MA (13), MD (1), ME (1), MI (4), MN (5), MO (2), MS (1), NC (11), ND (1), NE (3), NH (2), NJ (8), NM (2), NY (18), OH (9), OK (1), OR (9), PA (7), RI (2), SC (1), SD (3), TN (5), TX (7), UT (9), VA (1), WA (17), WI (1), WV (1), and WY (2). Because the main Salmonella Montevideo outbreak PFGE pattern is commonly occurring in the United States, public health investigators may determine that some of the illnesses are not part of this outbreak.
Salmonella Senftenberg, a different serotype of Salmonella, has been found in food samples from retail and a patient household during this outbreak investigation. PulseNet identified 6 persons who had illness caused by Salmonella Senftenberg with matching PFGE patterns between July 1, 2009 and today. Public health officials have interviewed 5 of the 6 ill persons with this strain of Salmonella Senftenberg and determined that one consumed a recalled salami product during the week before their illness began. These six cases are not included in the overall case count reported above.
Among the persons with reported dates available, illnesses began between July 4, 2009 and February 5, 2010. Infected individuals range in age from < 1 year old to 93 years old and the median age is 39 years. Fifty-three percent of patients are male. Among the 176 patients with available information, 46 (26%) were hospitalized. No deaths have been reported.
The outbreak can be visually described with a chart showing the number of persons who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after February 3, 2010 might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks. Please see the Salmonella Outbreak Investigations: Timeline for Reporting Cases for more details.
Investigation of the Outbreak
During January 16-21, 2010, CDC and public health officials in multiple states conducted an epidemiologic study by comparing foods eaten by 41 ill and 41 well persons. Preliminary analysis of this study has suggested salami as a possible source of illness. Ill persons (58%) were significantly more likely than well persons (16%) to report eating salami. Additionally, 16 ill persons have been identified who purchased the same type of sliced salami variety pack at different grocery store locations before becoming ill; Three additional ill persons have been identified who purchased a similar type of sliced salami deli tray before becoming ill. These data suggest this product is the source of some of these illnesses. This sliced salami variety pack and sliced salami deli tray were recently recalled by Daniele International Inc. CDC and public health officials in multiple states continue to interview ill persons to ask them about the foods they ate during the week before they became ill as well as to collect shopper card information.
FSIS has issued several news releases announcing Daniele International Inc. recalled products and has compiled a master list of these products for easy reference by consumers. News releases were issued on January 23, 2010 (initial recall), January 31st (expanded recall), February 4th (updated information of January 23rd recall), and February 16th (expanded recall). Many of these products can have an extended shelf life of up to one year. These products were distributed to retail establishments nationwide.
Laboratory Testing of Products and Ingredients
The initial recall followed isolation of Salmonella Senftenberg in a private laboratory from a retail sample of a salami product produced by Daniele International; this product was different than the sliced salami variety pack purchased at different grocery store locations by the 16 ill persons, but the same product purchased by three ill persons. FSIS reviewed and affirmed these private laboratory results. The Salmonella Senftenberg strain initially found by the private laboratory was different from the Salmonella Montevideo strain causing the outbreak. However, the Washington State Department of Health subsequently tested the bacterial culture provided by the private laboratory (the salami was not provided) and identified two different Salmonella serotypes: Salmonella Senftenberg (the strain found by the private lab) and Salmonella Montevideo indistinguishable from the outbreak strain. In addition, the Iowa Department of Public Health and public health officials in Plymouth County, Iowa investigated a patient with Salmonella Montevideo infection indistinguishable from the outbreak strain and discovered an open sliced salami variety pack frozen at the patient's home. The patient had eaten this product before becoming ill. This sliced salami variety pack was the same as that purchased by 16 other ill persons. Using DNA analysis, the University of Iowa Hygienic Laboratory (Iowa's public health laboratory) confirmed that the Salmonella isolated from this leftover salami was indistinguishable from the outbreak strain of Salmonella Montevideo.
The recall was expanded as a result of a confirmed finding of Salmonella in an unopened salami product reported by the Illinois Department of Public Health. The product was sampled during the course of an ongoing investigation of a multistate outbreak of Salmonella Montevideo illnesses. The product tested was not included in the previous recall issued January 23, 2010, but is a similar type of product bought by customers who later became sick and were identified as part of the Salmonella Montevideo investigation. Subsequent testing revealed that the product contained the Salmonella Senftenberg strain. The company believes that black pepper is a possible source of Salmonella contamination.
On January 28th, the Rhode Island Department of Health announced that test results revealed that an opened container of black pepper used in the manufacturing of at least some of the recalled products was positive for Salmonella Montevideo and that the DNA fingerprint matched the outbreak strain: http://www.ri.gov/press/view/10647.
On February 17, results from laboratory testing of product from Illinois revealed that the product contained the Salmonella Senftenberg strain.
The FDA is actively investigating the supply chain of the black pepper used in the manufacturing of the recalled meat products. The Agency has collected and analyzed nearly 70 domestic and imported black pepper samples. All of FDA’s samples have tested negative for the outbreak strain of Salmonella. The Agency continues to investigate the possibility that pepper might be responsible for this outbreak and has not yet reached any conclusion.
CDC and its public health partners are continuing the epidemiologic investigation to verify that the outbreak is controlled. CDC, USDA-FSIS, and FDA continue to work closely to identify the specific products or ingredients that became contaminated and how the contamination occurred and to identify any other food vehicles that may be involved.
Unique Features of this Outbreak Investigation
- There are over 2,500 serotypes of Salmonella. Serotype Montevideo is in the top 10 most common Salmonella serotypes. Because the outbreak strain of Salmonella Montevideo is the most common pattern for serotype Montevideo based on DNA analysis, detecting an outbreak is challenging. CDC developed and tested a new statistical method for figuring out whether the cases reported to the PulseNet database were above what was expected based on historical trends.
- Shopper card information was successfully used to determine specific brands of a product suspected to cause illness. Ill persons gave permission for public health officials to retrieve purchase information based on shopper card numbers. Additionally, a case-control study was conducted which suggested that the individuals who became ill ate salami/salame products a week prior to becoming ill.
- The recalled product contains ingredients regulated by two different federal agencies, USDA and FDA, both of which are fully engaged in this investigation. USDA regulates the meat used in the salami/salame and FDA regulates the spices.
Clinical Features/Signs and Symptoms
Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps 12-72 hours after infection. Infection is usually diagnosed by culture of a stool sample. The illness usually lasts from 4 to 7 days. Although most people recover without treatment, severe infections may occur. Infants, elderly persons, and those with weakened immune systems are more likely than others to develop severe illness. When severe infection occurs, Salmonella may spread from the intestines to the bloodstream and then to other body sites and can cause death unless the person is treated promptly with antibiotics.
More general information about Salmonella can be found here under Salmonella FAQs.
Advice to Consumers
- Recalled products may still be in grocery stores and in consumers' homes, including in the freezer. Recalled products should not be consumed. Consumers are advised to review the list of all recalled products.
- Consumer with questions regarding the recall should contact the Daniele International, Inc. Hotline at (888) 345-4160 and its PR contact, Levick Strategic Communications at (202) 973-1335.
- If you have a recalled product, do not eat it; return it to the place of purchase or dispose of it in a closed plastic bag and placed in a sealed trash can to prevent people or animals, including wild animals, from eating it.
- No illness has been linked to salami products produced by other companies.
- Consumers with food safety questions can "Ask Karen," the FSIS virtual representative available 24 hours a day at AskKaren.gov.
- The toll-free USDA Meat and Poultry Hotline 1-888-MPHotline (1-888-674-6854) is available in English and Spanish and can be reached from 10 a.m. to 4 p.m. EST Monday through Friday. Recorded food safety messages are available 24 hours a day.
- Consumers without Internet access can also call 1-800-CDC-INFO (1-800-232-4636), 24 hours a day, 7 days a week, for product recall information from the USDA-FSIS website and for other information on salmonellosis.
- Persons who think they might have become ill from eating a recalled product should consult their health care providers. Infants, elderly persons, and persons with impaired immune systems are more likely than others to develop severe illness.
- Press release from Rhode Island Department of Health (January 28, 2010)
- Potentially Tainted Italian Sausage Recalled, Products from Rhode Island-based Firm May be Contaminated with Salmonella - Los Angeles County Department of Public Health
- Hygienic Laboratory First to Confirm Salmonella in Nationwide Outbreak - University of Iowa
- Salmonella Outbreak Prompts Salami Recall, Oregon Public Health Officials are Tracking Cases Throughout the State [PDF - 3 pages] - Oregon Department of Human Services
CDC's Role in Food Safety
As an agency within the U.S. Department of Health and Human Services (HHS), CDC leads federal efforts to gather data on foodborne illnesses, investigate foodborne illnesses and outbreaks, and monitor the effectiveness of prevention and control efforts. CDC is not a food safety regulatory agency but works closely with the food safety regulatory agencies, in particular with HHS’s U.S. Food and Drug Administration (FDA) and the Food Safety and Inspection Service within the United States Department of Agriculture (USDA). CDC also plays a key role in building state and local health department epidemiology, laboratory, and environmental health capacity to support foodborne disease surveillance and outbreak response. Notably, CDC data can be used to help document the effectiveness of regulatory interventions.
Previous Updates on this Outbreak
- February 18, 2010
- February 16, 2010
- February 11, 2010
- February 9, 2010
- February 5, 2010
- February 3, 2010
- February 1, 2010
- January 29, 2010
- January 26, 2010
- January 25, 2010
- January 23, 2010
- January 22, 2010