According to new data from the Centers for Disease Control and Prevention, foodborne illness continued to increase in frequency through 2019 compared with the years between 2016 and 2018. The number of infections caused by Listeria, Salmonella, and Shigella remained stable, while all other pathogens except one increased. Salmonella serotype Enteritidis infections did not increase—but those Salmonella infections caused by serotype Typhimurium decreased.
For Jaydee Hansen, policy director at the Center for Food Safety in Washington D.C., the principal factor driving increased infection is the industrialization of the food supply. “Just as when we urge people to practice physical distancing to prevent spreading COVID,” Hansen tells Food Quality & Safety, “The lack of physical distancing in any of our large poultry and livestock production facilities means that animals easily pass on pathogens. Poor hygiene practices that allow rodents and birds access to feeds used for animals also spreads pathogens.”
At the same time, Hanson credits a lack of clean water, sometimes related to the development of concentrated animal feeding operations (CAFOs) on land adjacent vegetable farms. “Thirty years ago,” she says, “no one would have thought that leafy greens would be the second source of E. coli infections, but the use of water and soil obtained near CAFOs has transferred E. coli to the leafy greens.”
Jennifer McEntire, VP of food safety and technology for fresh-produce industry group United Fresh Produce Association, notes another important explanation for increasing rates of infection: increasingly precise diagnostic tools able to determined the pathogen that caused an illness. In particular, McEntire credits new diagnostic tools for helping identify the illness cyclosporiasis (caused by Cyclospora). “It’s likely that people had cyclosporiasis before and just didn’t know it,” McEntire says. “Now we know, and those numbers are captured. The extent to which the apparent rise in cases of Cyclospora is due to better diagnostics, versus a true increase in illness, is unknown.”
Full Analysis Not Yet Available
McEntire has approached CDC for information about which food items were linked with which pathogens, but she says a full analysis is not yet complete. She notes that industry and consumers have taken careful note of risks associated with leafy greens, but she is uncertain what proportion of illnesses were connected to foods such as ground beef, flour, and other potential pathogen vectors. At the same time, the industry needs as much information as it can get, and McEntire stresses that research on fresh produce is new when compared with some other commodities.
“More importantly, the industry would benefit from the translation of research, so that they understand how to apply it to their operations,” she says, adding that cooperative extension services that help business of all size assess risks and implement mitigations would be very helpful.
For Hansen, the declining number of illnesses associated with Salmonella serotypes Typhimurium and Heidelberg are important, and may be connected with a trend in egg producers vaccinating flocks for strains of Salmonella beyond the one strain required by the FDA. “The declines in these and in STEC O157 infections provide supportive evidence that targeted control measures are effective,” Hansen says. “In particular, measures targeting specific Salmonella serotypes, including vaccination of broiler poultry flocks, might result in a marked decrease in human illness, as has been seen in the United Kingdom.”
Additionally, Hansen calls for the U.S. sector to fully implement FSMA, new or revised meat and poultry performance standards, and enhanced training and guidance for industry and inspection personnel. These factors are particularly important for food safety during a time of pandemic.
“USDA is moving in the wrong direction speeding up lines in the meat and poultry packing plants,” Hansen says. “We used to be able to say the USDA seal on a package of meat or poultry was some assurance of safety. Now with COVID infections spreading in meat packing plants (in part because of increased line speeds) we are seeing that the inspections of animals for signs of pathogen infection can’t be happening and workers are getting COVID from each other.”