title: Control of foodborne pathogens on fresh-cut fruit by a novel strain of Pseudomonas graminis.
abstract: The consumption of fresh-cut fruit has substantially risen over the last few years, leading to an increase in the number of outbreaks associated with fruit. Moreover, consumers are currently demanding wholesome, fresh-like, safe foods without added chemicals. As a response, the aim of this study was to determine if the naturally occurring microorganisms on fruit are "competitive with" or "antagonistic to" potentially encountered pathogens. Of the 97 and 107 isolates tested by co-inoculation with Escherichia coli O157:H7, Salmonella and Listeria innocua on fresh-cut apple and peach, respectively, and stored at 20 °C, seven showed a strong antagonistic capacity (more than 1-log unit reduction). One of the isolates, CPA-7, achieved the best reduction values (from 2.8 to 5.9-log units) and was the only isolate able to inhibit E. coli O157:H7 at refrigeration temperatures on both fruits. Therefore, CPA-7 was selected for further assays. Dose-response assays showed that CPA-7 should be present in at least the same amount as the pathogen to adequately reduce the numbers of the pathogen. From the results obtained in in vitro assays, competition seemed to be CPA-7's mode of action against E. coli O157:H7. The CPA-7 strain was identified as Pseudomonas graminis. Thus, the results support the potential use of CPA-7 as a bioprotective agent against foodborne pathogens in minimally processed fruit.
authors.affiliation: Food Technology Department, Lleida University, XaRTA-Postharvest, Agrotecnio Center, Rovira Roure 191, 25198 Lleida, Catalonia, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Alegre
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Viñas
authors.forename: Josep
authors.initials: J
authors.lastname: Usall
authors.forename: Neus
authors.initials: N
authors.lastname: Teixidó
authors.forename: Marian J
authors.initials: MJ
authors.lastname: Figge
authors.forename: Maribel
authors.initials: M
authors.lastname: Abadias
mesh_terms: D000898:Antibiosis; D019453:Escherichia coli O157 / Q000254:growth & development* / Q000502:physiology; D005519:Food Preservation / Q000379:methods*; D005638:Fruit / Q000382:microbiology; D008087:Listeria / Q000254:growth & development* / Q000502:physiology; D027845:Malus / Q000382:microbiology*; D027861:Prunus / Q000382:microbiology*; D011549:Pseudomonas / Q000502:physiology*; D012475:Salmonella / Q000254:growth & development* / Q000502:physiology