CDC Breaks Down Common Causes of Foodborne Illness

During 2009 and 2010, beef, dairy, fish, and poultry were associated with the largest number of foodborne disease outbreaks, according to the Centers for Disease Control (CDC) (Morbidity and Mortality Weekly Report, January 25, 2013). During the preceding 11 years, beef, fish, and poultry were consistently among the commodities most commonly associated with outbreaks. The large number of outbreaks caused by unpasteurized dairy products is consistent with findings that more outbreaks occur in states that permit the sale of unpasteurized dairy products. Sixty percent of states permit sales of raw milk in some form, according to a 2011 survey by the National Association of State Departments of Agriculture, the CDC commented.

According to the CDC, 675 foodborne disease outbreaks were reported in 2009 and 852 in 2010. Of the outbreaks with a single cause, norovirus was the most commonly reported, accounting for 42 percent of outbreaks. Salmonella was second, accounting for 30 percent of outbreaks. Among the 299 outbreaks attributed to a food composed of ingredients from mutually exclusive food commodities, those most often implicated were beef (13 percent), dairy (12 percent), fish (12 percent), and poultry (11 percent). The commodities in the 299 outbreaks associated with the most illnesses were eggs (27 percent of illnesses), beef (11 percent), and poultry (10 percent).

The reported outbreaks during 2009 and 2010 resulted in 29,444 cases of illness; 1,184 hospitalizations; and 23 deaths. Public health, regulatory, and food industry professionals can use this information when creating targeted control strategies along the farm-to-table continuum for specific agents, specific foods, and specific pairs of agents and foods. This information also supports efforts to promote safe food-handling practices among food workers and the public.

Among the 790 outbreaks with a single confirmed cause, bacteria caused 413 (52 percent) outbreaks, viruses caused 336 (42 percent), chemicals and toxins caused 39 (5 percent), and parasites caused 2 (0.2 percent). Salmonella was next, causing 234 (30 percent) of confirmed, single-etiology outbreaks and 7,039 (36 percent) illnesses. Among the 225 confirmed Salmonella outbreaks with a serotype reported, Enteritidis was the most common serotype with 76 outbreaks (34 percent). Shiga toxin–producing Escherichia coli (STEC) caused 58 confirmed, single-etiology outbreaks, of which 53 were caused by serogroup O157.

Thirty-eight multistate outbreaks were reported in 2009 and 2010. Twenty-one were caused by Salmonella, 15 by STEC (13 O157, one O145, and one O26), and two by Listeria. The causative agent was isolated from an implicated food in 11 multistate outbreaks. Five of the multistate outbreaks were caused by Salmonella (in alfalfa sprouts, ground turkey, shell eggs, and a frozen entrée). Six were caused by STEC (in ground beef, unpasteurized Gouda cheese, multiple unpasteurized cheeses, hazelnuts, and cookie dough).

Among the 766 outbreaks with a known single setting where food was consumed, 48 percent were caused by food consumed in a restaurant or deli, and 21 percent were caused by food consumed in a private home. Forty-three outbreaks resulted in product recalls. The recalled foods were ground beef (eight outbreaks), sprouts (seven), cheese and cheese-containing products (six), oysters (five), raw milk (three), eggs (three), and salami (ground pepper), bison, sirloin steak, unpasteurized apple cider, cookie dough, frozen mamey fruit, hazelnuts, Romaine lettuce, ground turkey burger, tuna steak, and a frozen entrée (one each).