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Salmonellosis: The Problem

Opinion

In 2013, the U.S. Centers for Disease Control and Prevention (CDC) reported that more than 500 people were sickened by seven strains of Salmonella Heidelberg linked to chicken. However, salmonellosis caused by Salmonella Heidelberg is only in fourth place, according to CDC’s outbreak data; in 2011, it was only in seventh place.

Salmonellosis is “old news.” Similar to automobile accidents, salmonellosis is so common that only extraordinary outbreaks make the news. And yet, according to CDC, it is the deadliest of foodborne outbreaks. There has been more than 50 years of scientific discussion of “The Salmonella Problem,” including options for control. There are successes in controlling Salmonella animal pathogens dating back more than 75 years, but there have been few incentives for controlling Salmonella human pathogens.

In this and following articles, I will discuss the problem, research, regulatory precedents, solutions, options and arguments for and against declaring Salmonella as an adulterant.

The current toll of 550 cases in the 2013 Salmonella Heidelberg outbreaks strongly indicates that these strains of Salmonella are ordinarily injurious to health in the hands of consumers. According to the law, 21 USC 453(g)(1) and 21 USC 601(m)(1), that meets the definition of an adulterant.

After the 2005 Washington state Salmonella Heidelberg outbreak, some in the USDA Food Safety Inspection Service (FSIS) proposed declaring Salmonella Heidelberg an adulterant. It failed, I was told, because of political pressures. Some of the arguments against declaring Salmonella an adulterant in raw meat or poultry have included: People should just cook it, the warning labels on packages are adequate, Salmonella is naturally occurring and impossible to eradicate, not all Salmonella are pathogenic, and the burden on producers and processors would be onerous.

More than a half-century ago, Flippin and Eisenberg in “The Salmonella Problem” discussed the emerging salmonellosis outbreaks and antimicrobial resistance. Following up in 1974, Hornick wrote, “However, in the 14 years since his report (Flippin) there has been a continued increase in the Salmonella problem.”

There are more than four decades of science on how to eliminate or reduce Salmonella in food animal production facilities, but, except for animal pathogens, there has been little economic incentive to implement those results. More than three decades ago, John Silliker wrote, “The status of human salmonellosis is not much different today than it was 15 years ago. Figure 1 is a continuation of the same tired graph many of us have been leaning on for years (3). The problem is a little greater, certainly not less. Those of us who have used such graphs have always been quick to insert a non-warranty: ‘This is only the tip of the iceberg.’ How great is the real problem?”

John was a member of the National Academy of Science (NAS) Committee on Salmonella, which published, “An Evaluation of the Salmonella Problem,” in 1969. In 1970, the Microbiological Subgroup of the USDA Food Safety Committee published, “A Review of the NAS-NRC Report. An Evaluation of the Salmonella Problem.” The Subgroup, composed of members from the USDA ARS or the USDA Consumer Marketing Service (now FSIS), concurred or agreed with every recommendation. Implementation of those recommendations was another matter.

The significance of salmonellosis is mentioned in one goal of FSIS’ FY 2014 Annual Performance Plan, whose theme is “Prevent Foodborne Illness.” The goal for:

Foodborne Illnesses Attributable to FSIS products/100,000 persons

Salmonella 4.88

Lm 0.13

E. coli O157:H7 (sic) 0.32

Thus, the goal for salmonellosis is 15 times greater than the next highest goal. Sadly, one of the actions for the Office of Public Affairs and Consumer Education appears to be apologize for failure: “Implement at least two tactics for providing Salmonella-related food safety messages to the public, including why Salmonella is more challenging to control than other pathogens.”

Strains of Salmonella are the most deadly foodborne pathogens. In a 2011 paper on deaths associated with foodborne bacterial pathogens, Barton Behravesh, et alia, stated, “Conclusions. Salmonella and Listeria remain the leading causes of death in the United States due to bacterial pathogens transmitted commonly through food.” In a 2013 update, CDC’s 2011 estimates showed nontyphoidal Salmonella topped the chart of “Domestically Acquired Foodborne Illnesses Resulting In Hospitalization,” with 35 percent of hospitalizations, and the chart of “Illnesses Resulting In Death,” with 28 percent.

Those data were taken from FoodNet, but it is not new information. CDC annual reports over the past three decades have shown that salmonellosis is the leading cause of foodborne bacterial deaths. The “specter of botulism” was used to secure the continued use of nitrites, but salmonellosis was deadlier. Before and after E. coli O157:H7 came to regulatory attention, salmonellosis still caused more annual deaths. Listeria monocytogenes dominated the 1990s and is still a tough problem, but the industry has developed and implemented controls. Salmonellosis still reigns supreme. It’s time to dethrone Salmonella.

References:

Barton Behravesh, Casey; Timothy F. Jones, Duc J. Vugia, Cherie Long, Ruthanne Marcus, Kirk Smith, Stephanie Thomas, Shelley Zansky, Kathleen E. Fullerton, Olga L. Henao, Elaine Scallan, and FoodNet Working Group. 2011. Deaths Associated With Bacterial Pathogens Transmitted Commonly Through Food: Foodborne Diseases Active Surveillance Network (FoodNet), 1996-2005 J Infect Dis. (2011) 204 (2): 263-267 doi:10.1093/infdis/jir263)

Flippin, Harrison F. and George M. Eisenberg. 1960. The Salmonella Problem. Trans Am Clin Climatol Assoc. 1960; 71: 95-106.

Hornick, R. B. 1974. Jeremiah Metzger lecture: Salmonella infections–newer perspectives of an old infection. Trans Am Clin Climatol Assoc. 1974; 85: 164-174.

Microbiological Subgroup of the USDA Food Safety Committee. 1970. Food Protections by the Department of Agriculture. A Review of the NAS-NRC Report.

National Academy of Sciences/National Research Council/Committee on Salmonella. 1969. An Evaluation of the Salmonella Problem. Prepared by the Salmonella Committee of the National Research Council, Washington, DC.: National Academy of Sciences, Publication No. 1683.

Silliker, J.H. 1982.The Salmonella problem: current status and future direction. Journal of Food Protection. May 1982. v. 45 (7).

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