Recent foodborne Salmonella outbreaks have been associated with chocolate and peanut butter. Although Salmonella cannot grow in any of these low-water foods, the cells survive and become more resistant to heat treatment, which has contributed to recent outbreaks. New research published in Applied and Environmental Microbiology suggests that oil formulations with food-grade organic acids can kill dried Salmonella on stainless steel surfaces.
“Cleaning and sanitizing manufacturing environments are critical to a safe food supply,” said lead author Lynne McLandsborough, Ph.D., a professor of food sciences at the University of Massachusetts Amherst. However, water-based cleaning is rarely used in peanut butter processing because it promotes microbial growth. “Also, as anyone who has baked peanut butter cookies can tell you, peanut butter and water don’t mix, and cleaning with water is a challenge,” McLandsborough said.
Instead, manufacturers often remove residual peanut butter from manufacturing systems using hot oil, followed by overnight cooling and the application of flammable, alcohol-based sanitizing agents.
In the study, McLandsborough and colleagues dried Salmonella on stainless steel surfaces in controlled relative humidity. They then coated the dried bacteria with various organic acid oils, varying the acid type, concentration, contact time, and treatment temperature to identify highly antimicrobial formulations.
Using peanut oil mixed with acetic acid at a concentration about half that of household vinegar and applying heat, “the destruction was much greater than expected, indicating a synergistic effect,” McLandsborough said. “Our results show that acidified oils could be used as an effective means of sanitation in low-moisture food processing facilities, where water-based cleaning can be challenging.”
“To our knowledge, the use of oils as organic acid carriers is a novel approach to deliver antimicrobial compounds against foodborne pathogens,” said McLandsborough. Therefore, the research may lead to the adaptation of oil-based systems for industrial cleaning, for example, of machinery for processing chocolate and peanut butter, McLandsborough said. “That would allow for more frequent cleaning, increasing the safety of these products.”
Materials provided by the American Society for Microbiology. Note: content can be edited for style and length.
