Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2018
Publication Date: 7/3/2018
Citation: Guo, M., Jin, Z.T., Gurtler, J., Fan, X., Yadav, M.P. 2018. Inactivation of E.coli O157:H7 and Salmonella on fresh strawberries by antimicrobial washing and coating. Journal of Food Protection. 81(8):1227-1235.
Interpretive Summary: Fresh strawberries have a short shelf life and were associated with foodborne outbreaks. This study evaluated the effectiveness of antimicrobial wash (AW) and coating treatments (AC), either individually or in combination (AW+AC), in reducing populations of E. coli O157:H7 and Salmonella in strawberries. AW+AC treatments achieved the greatest inactivation of pathogens and native microflora. Both AW+AC and AC treatments preserved the color, texture, and appearance of strawberries throughout 3 weeks’ storage at 4 degree C. This study demonstrates a method to improve the microbiological safety, shelflife and quality of strawberries.
Technical Abstract: Antimicrobial washing, antimicrobial coating, and a combination of both treatments were evaluated for their ability to inactivate artificially inoculated foodborne pathogens and native microflora on strawberries stored at 4 degrees C. Strawberries were inoculated with a six-strain composite of E. coli O157:H7 and Salmonella spp., treated with antimicrobial washing (AW), antimicrobial coating (AC), or washing followed by coating (AW+AC), and stored at 4 degrees C for 3 weeks. The washing solution contained 90 ppm peracetic acid and the coating solution consisted of chitosan (10 mg/ml), allyl isothiocyanate (AIT, 10 ul/ml), and corn-bio fiber gum (C-BFG, 5 ug/ml). The effectiveness of the antimicrobial treatments against pathogens and native microflora on strawberries and their impacts on fruit quality (appearance, weight loss, color, and firmness) were determined. By the end of storage, pathogen populations on strawberries were 2.5 (AW+AC), 2.9 (AC), 3.8 (AW) and 4.2 log CFU (Control), respectively. AW+AC treatments also achieved the greatest inactivation of native microflora, followed by AC treatment alone. AW+AC treatments showed an additional antimicrobial effectiveness against pathogen and native microflora. Both AW+AC and AC treatments preserved the color, texture, and appearance of strawberries throughout storage. The coating treatments (AW+AC and AC alone) further reduced the loss of moisture from fruits throughout storage. AW treatment was the least effective in reducing populations of pathogens and native microflora and in maintaining the quality of strawberries throughout storage. This study demonstrates a method to improve the microbiological safety, shelflife and quality of strawberries.