Disease researchers say infections from foodborne pathogens increased in 2018 when compared with 2015-17, with the increasing use of culture-independent diagnostic tests.

The overall safety of food eaten in the U.S. is not trending in a positive direction according to an article published in the weekly Morbid and Mortality Weekly Report from the Centers for Disease Control and Prevention.

“The incidence of Cyclospora infections increased markedly, in part related to large outbreaks associated with produce,” the researchers reported.

“The number of human infections caused by Campylobacter and Salmonella, especially serotype Enteritidis, remains high.”

Preliminary analysis of the data shows the increasing using culture-independent diagnostic tests (CIDTs) to detect enteric infections is helping identify and quantify foodborne illness outbreaks. The CIDTs benefit public health surveillance by identifying pathogens not routinely detected by previous methods but complicate data interpretation, according to the research team.

The research report says inadequate prevention measures in the food industry as a major contributing factor to the increasing prevalence of foodborne illness patients in the United States.

“More targeted prevention measures are needed on produce farms, food animal farms, and in meat and poultry processing establishments to make food safer and decrease human illness,” according to the report.

The research team reported that in 2018, a multi-state surveillance network —  the CDC’s Foodborne Diseases Active Surveillance Network (FoodNet) — identified more than 25,600 infections. Of those patients, almost 5,900 had to be admitted to hospitals; 120 of the confirmed patients died.

FoodNet conducts active, population-based surveillance for laboratory-diagnosed infections caused by Campylobacter, Cyclospora, Listeria, Salmonella, Shiga toxin–producing E. coli (STEC), Shigella, Vibrio, and Yersinia in 10 sites. Those 10 locations cover 15 percent of the U.S. population, which was about 49 million people in 2017.

For every 100,000 people in the United States, the researchers compiled numbers showing the incidence of infections. Their findings include:

• Campylobacter at 19.5 per 100,000;
• Salmonella at 18.3;
• STEC at 5.9;
• Shigella at 4.9; 
• Vibrio at 1.1; 
• Yersinia at 0.9; 
• Cyclospora at 0.7; and 
• Listeria at 0.3. 

“Compared with 2015-2017, the incidence significantly increased for Cyclospora at 399 percent, Vibrio at 109 percent, Yersinia at 58 at 58 percent, STEC at 26 percent, Campylobacter at 12 percent, and Salmonella a 9 percent,” the researchers reported.

“The number of bacterial infections diagnosed by CIDT — with or without reflex culture§) — increased 65 percent in 2018 compared with the average annual number diagnosed during 2015–2017. The increase ranged from 29 percent for STEC to 311percent for Vibrio.”

Some of the other statistics compiled by the research team include:

Abbreviations in chart:
CI = confidence interval; IR = incidence rate.
* Connecticut, Georgia, Maryland, Minnesota, New Mexico, Oregon, Tennessee, and selected counties in California, Colorado, and New York.
^† Data are preliminary.
^§ Per 100,000 population.
^¶ Increase or decrease.
** All serogroups were combined because it is not possible to distinguish among them using culture-independent diagnostic tests.