Norovirus, Salmonella and Restaurants are Key in CDC’s Latest Outbreak Report
CDC’s annual Foodborne Disease Outbreak Report published in September provided data on the 841 foodborne disease outbreaks that occurred throughout the U.S. in 2017, resulting in 14,481 illnesses, 827 hospitalizations, 20 deaths, and 14 food recalls. While unlikely to be surprising to many, the statistics did provide some eye-opening information, particularly as relates to Salmonella, norovirus, and restaurants.
Although Listeria was a key focus of FDA “swabathons” in 2017, and a major E. coli leafy greens outbreak occurred, the two most frequently reported confirmed causes of outbreaks and associated illnesses in that year were actually Norovirus and Salmonella. Norovirus was the cause of:
140 outbreaks, 35% of confirmed single-pathogen outbreaks.
4,092 illnesses, 46% of confirmed single-pathogen illnesses.
40 hospitalizations, 6% of confirmed single-pathogen, outbreak-related hospitalizations.
4 deaths, 20% of outbreak-related deaths.
Salmonella was the cause of:
113 outbreaks, 29% of confirmed single-pathogen outbreaks.
3,007 illnesses, 34% of confirmed single-pathogen illnesses.
472 hospitalizations, 66% of confirmed single-pathogen, outbreak-related hospitalizations.
8 deaths, 40% of outbreak-related deaths.
Additionally, Salmonella was responsible for 63% of all multistate outbreaks (20 of the 32 multistate outbreaks). The food source of these was confirmed in 12 outbreaks, suspected in 6, and not identified in 2. Salmonella also was the most cited of confirmed pathogen-food pairs responsible for the most illnesses, hospitalizations, and deaths. These included
Illnesses from Salmonella in turkey (580), fruits (421), chicken (299).
Hospitalizations from Salmonella in fruits (124), kratom powder (54), vegetable row crops (35).
Deaths from Salmonella in fruits (2).
Although E. coli (STEC) and Listeria were not listed as top causes in 2017, they were the second and third leading causes of multistate outbreaks, with E. coli implicated in 6 and Listeria in 5; and they led to deaths, with Listeria causing 3 outbreak-related deaths and E. coli, 1. Additionally, E. coli caused 513 illnesses and 111 hospitalizations.
Related to specific foods, the single food categories associated with the most outbreaks were Mollusks, such as oysters (41 outbreaks), fish (37), chicken (23), and beef (19). In addition to summarizing the pathogens and foods associated with outbreaks, the report assesses outbreak settings. The result: Restaurants were linked to outbreaks more often than any other place where food was prepared. It wasn’t a new statistic, nor does it seem that there has been much change in the intervening years, as a high percentage of foodborne illness is still caused by mishandling in foodservice facilities and homes.
Of the 761 outbreaks and 12,502 illnesses in 2017 with a reported single location where food was prepared, 489 outbreaks (64%) and 5,533 associated illnesses (44%) were attributed to foods prepared in a restaurant. Most (366) occurred at establishments with sit-down dining.
While the report provides significant data for assessing and prioritizing food risk, CDC cautions that the findings do have limitations. (1) Only a small proportion of foodborne illnesses are identified as being associated with outbreaks, thus these may or may not reflect the statistics of sporadic (non-outbreak) foodborne illness or outbreaks that are not identified, investigated, or reported. (2) Many outbreaks had an unknown etiology and/or food. (3) Because agencies can submit, change, or delete reports in CDC’s outbreak surveillance system at any time, this analysis might differ from other reports. (4) Agents not currently known to cause illness are sometimes reported as a confirmed or suspected etiology.
CDC’s Foodborne Disease Outbreak Report summarizes data from the Foodborne Disease Outbreak Surveillance System, as submitted by state, local, and territorial public health agencies to the National Outbreak Reporting System (NORS), a platform for reporting enteric (gut) disease outbreaks due to food, water, animals and their environments, and from person-to-person transmission. The full 15-page report is available at https://www.cdc.gov/fdoss/pdf/2017_FoodBorneOutbreaks_508.pdf.
Some key messages we at TAG take from this report is that restaurants continue to be a major concern for outbreaks, and that Norovirus and Salmonella controls require constant vigilance. Outbreak statistics are always much easier to obtain and track than sporadic cases, and as the report points out, outbreaks can create a false impression of where the problems are when looking at the total numbers of foodborne illness cases. But overall we can see that foodborne illness outbreaks continue to be a major issue from both a public health and a reputational perspective, especially for restaurants.
About The Acheson Group (TAG) Led by Former FDA Associate Commissioner for Foods Dr. David Acheson, TAG is a food safety consulting group that provides guidance and expertise worldwide for companies throughout the food supply chain. With in-depth industry knowledge combined with real-world experience, TAG's team of food safety experts help companies more effectively mitigate risk, improve operational efficiencies, and ensure regulatory and standards compliance. www.AchesonGroup.com