The BrightFarms Salmonella outbreak that occurred in the summer of 2021 has been investigated by the FDA. In the report released today, the agency states that this is “believed to be FDA’s first domestic investigation of a foodborne illness outbreak associated with leafy greens” that were grown in a Controlled Environment Agriculture (CEA) operation. The CDC investigation of this outbreak is included in the relevant links section of the report.
The outbreak, which was associated with the consumption of packaged leafy greens from BrightFarm’s indoor hydroponic operation, sickened at least 31 people in four states. Twenty-six of 27 patients said they ate leafy greens before they got sick. The firm’s products were specifically named by 14 patients.
The outbreak strain of Salmonella Typhimurium from patient isolates were closely related genetically, which means that these patients likely got sick from eating the same food. There were no products available for comparison. This occurs often when a suspect food has a limited shelf life.
An on-site investigation was conducted by the FDA in July and August 2021. At the BrightFarms facility, leafy greens are grown in a soilless growth media in a climate-controlled room. The greens are transferred to production ponds located in large scale greenhouses. Plastic-lined growing ponds are filled with water sourced from a municipal water supply that is treated on-site through a four-stage sand filtration and UV system. Once in the growing ponds, the water is not treated or disinfected.
Several concerns were noted by FDA inspectors. First, the operation stored its nutrient-rich growth media used in production rafts in an outdoor location that was not adequately protected from animal intrusion, bird droppings, or water runoff. FDA’s sampling of raw materials at the time did not find any pathogens.
A water sample collected by the FDA inspectors from an active production pond found Salmonella Liverpool, which was not associated with the outbreak. While the leafy greens that contact pond water during production and harvest should not be used in the final products, FDA investigators saw that some lettuce leaves that contacted production pond water were not eliminated from harvest and post-harvest production. And there was no control to consistently exclude harvesting of leaves that may have come into contact with the pond water. In addition, condensate accumulated on the overhead chiller lines and dripped onto product located near growing ponds.
Firm personnel told the investigators that ponds were treated with hydrogen peroxide and peracetic acid solution when sampling found genetic E. coli in the water, but there was no procedure to ensure adequate pond water treatment.
Water samples were collected from a stormwater retention basin outside the BrightFarms operation’s property, about 25 feet from the CEA structure. One sample tested positive for the outbreak strain of Salmonella Typhimurium. Investigators did not find specific routes of contamination to or from areas surrounding the CEA operation, such as storm water runoff, infiltration by pests, or airborne transfer.
Finally, the firm did not adequately document that cleaning and sanitizing of equipment, tools, and buildings that were used in the growing operation is routinely conducted according to the company’s procedures.
In conclusion, the FDA identified certain conditions and practices at that facility that could result in contamination, including water management practices and general sanitation practices that were inadequate to prevent the introduction or spread of bacteria into the leafy greens. The firm is cooperating with the FDA and is voluntarily implementing improvements to its operation.
