Foodborne disease outbreaks topped 1,500 in two years, reports CDC

The CDC reported data for foodborne outbreaks for the US in 2009 and 2010 and said the information can be used when creating control strategies along the farm-to-table continuum for specific agents and foods.

The agency said it defined a foodborne disease outbreak as the occurrence of two or more similar illnesses resulting from ingestion of a common food.

During 2009–2010, 1,527 foodborne disease outbreaks (675 in 2009 and 852 in 2010) were reported, resulting in 29,444 cases of illness, 1,184 hospitalizations, and 23 deaths.

Of the illnesses, 1,184 (4%) resulted in hospitalization, said the CDC.

Responsible pathogen​

Salmonella caused the most outbreak-related hospitalizations with 583 (49%), followed by STEC with 190 (16%) and Norovirus with 109 (9%).

Outbreaks caused by Listeria resulted in the highest proportion of people hospitalized (82%), followed by Clostridium botulinum (67%), and paralytic shellfish poisoning outbreaks (67%).

Among the 23 deaths, 22 were attributed to bacterial etiologies (nine to Listeria monocytogenes, ​five Salmonella, four STEC O157, three Clostridium perfringens, ​andone Shigella), and one to norovirus.

Norovirus was the most common single laboratory-confirmed etiologic agent, accounting for 42% of outbreaks with salmonella second with 30%.

Salmonella Enteritidis was the most common serotype reported among 225 confirmed outbreaks with 34%.  

Shiga toxin–producing E.coli (STEC) caused 58 confirmed, single-etiology outbreaks, of which 53 were caused by serogroup O157.

Implicated foods​

Beef (13%) was implicated most often amongst 299 outbreaks attributed to a food composed of ingredients from a list of 17 food commodities, followed by dairy (12%), fish (12%), and poultry (11%).

The commodities in the 299 outbreaks associated with the most illnesses were eggs (27% of illnesses), beef (11%), and poultry (10%).

Forty-three outbreaks resulted in product recalls, noted the report.

These included ground beef (eight), 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).

Limitations​

The agency said the findings had limitations, including only a small proportion of foodborne illnesses reported each year are identified as associated with outbreaks and not all outbreaks are identified, investigated, or reported.

“Many reported outbreaks had an unknown etiology, an unknown food vehicle, or both, and conclusions drawn from outbreaks with a confirmed or suspected etiology or food vehicle might not apply to outbreaks with an unknown etiology or food vehicle. Even when a food is identified, the point of contamination is not always known or reported.”  ​

It also warned against comparisons with previous years’ results due to changes in the surveillance system implemented in 2009.