Foodborne outbreaks down but less being solved - CSPI

The report analyzes 10 years of outbreak data available from the Centers for Disease Control and Prevention (CDC), covering 2002-2011.

CSPI looked at 10,409 foodborne disease outbreaks reported to CDC​ between 2002 and 2011.

3,933 of them—responsible for 98,399 illnesses—were fully solved. “Solved” means that a contaminated food and pathogen were identified.

Outbreaks decreased?​

Foodborne illness outbreaks appear to have decreased by 42% from 2002 to 2011, said CSPI.

However, the group added that this did not mean that fewer Americans were getting sick.

The health advocacy group said that outbreak reporting rates may be down due to the increased use of culture-independent diagnostic testing by healthcare providers.

Many state and local health departments are understaffed and underfunded and foodborne illnesses do not require a physician’s assistance to treat, said the report.

The CDC pointed FoodQualityNews.com to its surveillance summary on foodborne outbreaks from 1998-2008, where it says that the number reported to them declined by 23% from 1998-2008.

“​We believe the lower number of outbreaks during this period is mostly due to reporting declines in one populous state. There were no trends suggesting a national reduction in state outbreak investigation and reporting,” ​it said.

“Of the 42 states with enough information to measure changes in the number of outbreaks reported over time, many improved or maintained stable reporting (20 improved, 6 maintained stable reporting).” ​

Reports lacking information​

During the years looked at by CSPI, between 57% and 68% of outbreaks reported annually to CDC lacked information, such as the contaminated food or contaminant.

The declines in complete and incomplete reporting may be due to falling budgets for public health departments in the latter half of the study period, said the CSPI.

The group said to develop risk-based interventions and design effective and efficient food safety hazard controls, robust outbreak data is needed. The best outbreak data come from solved outbreaks, where both the contaminated food and pathogen are identified.

In response, the CDC directed us to a Q+A on surveillance on foodborne disease outbreaks in 2009 and 2010, where it said it encourages states to report all foodborne disease outbreak investigations, even if the food vehicle is not determined.

“Even well-conducted investigations sometimes do not identify a food vehicle. There are many reasons for this – one is that sometimes most ill persons ate many of the same food items, so a single food can't be pinpointed.” ​

FDA and USDA regulated foods​

Between 2002 and 2011, FDA-regulated foods were responsible for 66.5% of outbreaks, USDA-regulated foods for 26% and 7.5% were caused by multi-ingredient foods regulated by USDA and FDA.

The produce category was the top category for outbreaks, with 667 (17% of the total) and 23,748 illnesses (24% of the total).

Produce, seafood, poultry, and beef were responsible for the largest number of solved foodborne illnesses during the past decade.

Those four categories were together linked to half of all attributed outbreaks (51%) and illnesses (48%).

Food categories​

When illnesses are considered together with consumption rates, red meats (beef and pork), poultry, and seafood products are far more likely to cause illness than fruits and vegetables, said CSPI.

The increase in dairy-associated outbreaks could be due to the increased popularity of unpasteurized dairy products, like queso fresco and raw milk.

Among USDA-regulated products, the most commonly identified pathogens were Salmonella species (spp.) in poultry products; Clostridium perfringens and E. coli O157:H7 in beef; Salmonella and Staphylococcus aureusin pork; and Salmonella, ​Clostridium perfringens and Norovirus in luncheon and other meats.

The most commonly identified causes of foodborne illness in FDA-regulated foods were Norovirus and Salmonella spp. in produce; Scrombrotoxin and Ciguatoxin in seafood; Campylobacter in dairy; and Salmonella spp. in eggs.

CDC’s Foodborne Outbreak Online Database (FOOD) is the product of a large and dynamic network of nationwide outbreak surveillance systems and the data used was downloaded on May 16, 2013.