L. Hannah Gould, Ph.D., Lead, National Outbreak Reporting Team, a unit of the Atlanta-based Centers for Disease Control and Prevention (CDC), told attendees that contaminated food eaten in the United States causes roughly one in six Americans to get sick per year. This results in 48 million illnesses, 128,000 hospitalizations and 3,000 deaths. Approximately 800 foodborne illness outbreaks are reported annually.
In using a Smart Phone analogy, Gould said, “Surveillance systems [including PulseNet, National Notifiable Diseases Surveillance System (NNDSS) and Laboratory-based Enteric Disease Surveillance (LEDS), National Antimicrobial Resistance Monitoring System (NARMS), the Listeria Initiative, FoodNet, Foodborne-Disease-Outbreak-Surveillance-System (FDOSS), CalciNet, and the National Voluntary Environmental Assessment Information System (NVEAIS)] are like apps — each has a different purpose.”
In discussing beef and foodborne disease outbreaks, Gould told her audience that more than 25 billion lbs. of beef are consumed in the US per year, 11–28 percent of US population consumes ground beef raw or undercooked — and that beef is among several categories that are each the third-most common food category associated with foodborne outbreaks and illnesses. Other food categories include fish, 17 percent; dairy, 11 percent; beef, mollusks, chicken and other categories, 9 percent; pork, fruit and vegetable row crops categories, 7 percent; turkey, 5 percent; grains-beans, 4 percent; and seeded vegetables and eggs, 3 percent.
Pathogens implicated in outbreaks attributed to beef from 2009-2013 include Shiga toxin-producing E.coli O157, 35 percent; Salmonella, 23 percent; Clostridium perfringens, 20 percent; no pathogen, 15 percent; Campylobacter jejuni, 4 percent; Shiga toxin-producing E.coli O26, 1 percent; Norovirus, 1 percent; and other-chemical/toxin, 1 percent, according to CDC preliminary and unpublished data.
E. coli O157 causes an estimated 96,000 illnesses, 3,200 hospitalizations and 31 deaths annually in the US. Those illnesses cost an estimated $405 million-plus annually. This pathogen is transmitted by food, water, directly between persons and due to contact with animals or their environment. E. coli O157 outbreaks from 2003-2012 in the US totaled 391 resulting in 4,930 illnesses, 1,274 (26 percent of illnesses) hospitalizations; 300 (6 percent) cases of physician-diagnosed HUS; and 34 (0.7percent) deaths.
Food is the most common mode of transmission in E. coli O157 outbreaks: food, 65 percent; animal contact, person-to-person and unknown are all 10 percent; waterborne, 4 percent; and environmental contamination, 1 percent.
Foods implicated in E. coli O157 outbreaks from 2003-2012 include: beef, 55 percent; leafy vegetables, 21 percent; dairy, 11 percent; other meats, 5 percent; fruits, 4 percent; sprouts, 2 percent; and poultry and buts, 1 percent each. In the beef category, it can be further broken down to ground beef, 69 percent; other, 17 percent; and steak, 14 percent. Within the steak category, sirloin contributed to four outbreaks; filet mignon, one outbreak; unknown type, five outbreaks; and mechanically tenderized beef, five outbreaks.
Settings where food was prepared in E. coli O157 outbreaks are as follows: Restaurant, deli, banquet facility, 40 percent; private home, 33 percent; other, 17 percent; institution, 9 percent; and fair, 1 percent.
In concluding her comments on E. coli O157 and beef, Gould noted that more outbreaks were reported during 2003-2012 than previous 20 years, although continued improvements in surveillance have been made.
Gould also relayed that Non-typhoidal Salmonella is the most common cause of bacterial foodborne illness and outbreaks in the US causing 1.2 million illnesses and 130 outbreaks per year. She added that Salmonella infections and outbreaks have not declined in 15 years despite control efforts. Cattle are known reservoirs of Salmonella, she said, and Salmonella can contaminate meat during slaughter and processing. Beef is the fourth-most common cause of Salmonella outbreaks, and Salmonella is not historically considered a contaminant (warranting automatic product recall) in beef.
Salmonella outbreaks attributed to beef from 1973-2011 totaled 95 causing 3643 illnesses with 318 (9 percent of illnesses) requiring hospitalizations. Types of beef implicated include roasts, 26 percent; ground beef, 23 percent; and other, 51 percent. Salmonella serotypes were Typhimurium, 19 percent; Newport, 17 percent; and Enteritidis, 10 percent, based on CDC, preliminary and unpublished data. Most outbreaks have been caused by ground beef since 2000 while most outbreaks were caused by roast beef in the 1970s and 1980s.
In conclusion regarding Salmonella in beef, Gould pointed out that beef-attributed outbreaks of salmonellosis have occurred regularly despite the fact that red meat consumption in the US dropped between 1970 to 2007; there has been a shift over time from roast-attributed to ground beef-attributed outbreaks of salmonellosis; most of the roast beef-attributed outbreaks occurred during 1975–1993; and nearly all of ground beef-attributed outbreaks occurred during 1993–2011.
Gould cautioned the audience that limitations in keeping track of outbreaks still exist. Reported outbreaks underrepresent the number that occur and not all outbreaks are identified, she said. Additionally, not all identified outbreaks are investigated or reported to CDC, and even well investigated outbreaks might not identify a food or pathogen. Finally, when food is implicated, information on the source and point of contamination is not always known or reported.
Gould made recommendations on how to prevent outbreaks associated with beef — educate consumers and food handlers; provide clear labeling of mechanically-tenderized beef; apply additional pathogen reduction methods (e.g., irradiation); judiciously use antibiotics in clinical medicine and animal husbandry; strengthen measures to control antimicrobial resistant Salmonella in beef destined for grinding; and continue to enhance surveillance of foodborne disease outbreaks and infections.