Abrasive brushing reduces pathogen biofilms at cantaloupe rind surface

Abstract

Foodborne pathogens constitute a major food safety risk for cantaloupe, and pathogen biofilms formed are particularly difficult to remove. The goal of this study was to evaluate abrasive brushing in removing biofilms from cantaloupe surface using Listeria monocytogenes V7 and Salmonella enterica serovar Typhimurium ATCC 13311 as models. Cantaloupe rind pieces were inoculated and then subjected to 30 min or 24 h incubations. The incubated rind pieces were subject to different washing and/or brushing procedures and then the bacterial cells were enumerated. Cryo-SEM showed planktonic cells after 30 min incubation, whereas biofilms formed at rind surfaces after 24 h incubation. For L. monocytogenes 30 min incubation group, the log reductions were 1.4 for brushing, 2.1 for brushing with diatomaceous earth (DE), 2.8 for peroxyacetic acid (PAA) washing, 4.2 for brushing with PAA, and 4.0 for brushing with DE and PAA. In contrast, for the 24 h incubation group, the log reductions were 0.4 for brushing, 1.5 for brushing with DE, 1.1 for PAA washing, 1.6 for brushing with PAA, and 3.0 for brushing with DE and PAA. Similar results were observed for the S. Typhimurium group. These outcomes showed the pathogen-removal efficacy of brushing with DE (abrasive brushing) in the presence of biofilms, suggesting the potential application of abrasive brushing in cleaning cantaloupe for improved food safety.

Keywords: Abrasive brushing; Biofilm; Cantaloupe; Diatomaceous earth; Food pathogens.