Cottonseed protein isolates, sanitizer and combinations inactivate Listeria monocytogenes and Salmonella enterica Serovar Typhimurium in vitro and on post-harvest seed

Authors: Olanya, Ocen; Mukhopadhyay, Sudarsan; He, Zhongqi; Gurtler, Joshua; UKUKU, DIKE - Retired ARS Employee

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2025
Publication Date: 8/11/2025
Citation: Olanya, O.M., Mukhopadhyay, S., He, Z., Gurtler, J., Ukuku, D.O. 2025. Cottonseed protein isolates, sanitizer and combinations inactivate Listeria monocytogenes and Salmonella enterica Serovar Typhimurium in vitro and on post-harvest seed. Journal of Food Safety. https://doi.org/10.1111/jfs.70029.
DOI: https://doi.org/10.1111/jfs.70029

Interpretive Summary: Inactivation of foodborne pathogens is of considerable importance to alleviate food safety risks and protect consumers. The use of biorational approaches to mitigate pathogenic bacteria is an attractive measure, as biodegradable products and generally recognized as safe (GRAS) sanitizers are effective and non-toxic. In this research, inactivation efficacy of cottonseed protein isolates (CSPI), chemical-based, GRAS sanitizer and their combinations against foodborne pathogens, Listeria monocytogenes and Salmonella Typhimurium, were tested in vitro and on post-harvest seed types. Significant antimicrobial activities of glandless and glanded CSPI against both pathogens were observed, as applications of CSPI (0.05%) in vitro resulted in >3 log reductions of Listeria and Salmonella. Pathogen reductions differed significantly among alfalfa, soybean, mungbean, and almond seeds. CSPI supplemented with GRAS sanitizer resulted in further pathogen reductions (>4 logs). Application of CSPI and GRAS sanitizer as biorational measures can enhance post-harvest food safety.

Technical Abstract: Pathogen contamination of produce is a food safety concern to consumers, food industry and governmental agencies. The use of biorational approaches to minimize food contamination can reduce food safety hazards. The objectives of this research were to evaluate the inhibition potential and inactivation efficacy of cottonseed protein isolates (CSPI), a chemical-based generally recognized as safe (GRAS) sanitizer and their combinations against Listeria monocytogenes and Salmonella Typhimurium on media, co-inoculations assays (in vitro) and on post-harvest seed types. Glanded (CSPI-Gd), glandless (CSPI-Gl) protein isolates were applied on pathogens in vitro and on seeds. CSPI-Gl and CSPI-Gd had significant (P<0.05) antimicrobial activity against both pathogens as revealed by inhibition assay data. Optical density at 600 nm (OD600) of pathogen culture plus cotton seed protein isolates (CSPI) demonstrated comparable biocidal effects of the GRAS sanitizer. Pathogen treatments by CSPI at 0.05% (~500 ppm) were effective in co-inoculation assays with >6.0 log reductions of Salmonella and >5.0 log reductions for Listeria observed in vitro. In co-inoculations of CSPI-Gl and CSPI-Gd plus sanitizer, increased pathogen reductions occurred. Salmonella and Listeria reductions on pathogen-inoculated seed types ranged from 0.50-2.68 logs, with enhanced bacterial inactivation by sanitizer supplementation. CSPI is an abundant and underutilized agricultural byproduct and its antimicrobial applications could be expanded as seed treatment appears plausible. Elucidation of inhibitory and inactivation properties of CSPI and GRAS sanitizer as biorational intervention approaches on foodborne pathogens and their subsequent utilization can enhance fresh produce food safety.