First report of the agricultural biocontrol agent Bacillus velezensis and foodborne outbreak due to rope spoilage in cakes.

This paper presents an outbreak involving retail bakery cakes and a celebration at a business with multiple sites. Bacillus spore-forming bacteria have been identified as the cause of "ropey bread" spoilage for over 100 years. Causative strains of rope spoilage include B. subtilis and other Bacillus species. Thirty-five employees identified as having been at a celebration event across 11 sites were questioned to characterize the amount of cake eaten, observations, and symptoms. No human specimens were obtained, but leftover cake was analyzed by the Ohio Department of Health Bureau of Public Health Laboratory. The odds that cake caused symptoms were 9.23 (1.02-83). The presence of odor decreased the amount eaten by 151 g (103-205 g), P = 0.001. Enteric symptoms developed 0.41-4.5 hours after exposure, with 5 of 12 cases having latent diarrhea. Cakes were positive for Bacillus velezensis. This appears to be the first mention of B. velezensis as a contributor to the re-emergence of rope spoilage in the bakery industry. Updates to the Bacillus taxonomy starting in 1973 may account for why B. subtilis and other Bacillus strains are historically listed without mention of B. velezensis as a cause of rope spoilage. Given the ability of B. velezensis to be an effective biocontrol agent and to grow at pH and water activity levels like many baked goods, there is a need to study issues along the entire food chain to balance the impact on biocontrol additives on food production and safety.IMPORTANCEThis appears to be the first mention of Bacillus velezensis as a contributor to the re-emergence of rope spoilage in the bakery industry. Given the ability of B. velezensis to be an effective biocontrol agent and to grow at pH and water activity levels like many baked goods, there is a need to study issues along the entire food chain to balance the impact on biocontrol additives on food production and safety.