title: The Efficiency of UVC Radiation in the Inactivation ofListeria monocytogeneson Beef-Agar Food Models.
abstract: The aim of this study is to evaluate the effect of meat content and surface smoothness on the deactivation ofListeria monocytogenesin beef-agar food models achieved by shortwave ultraviolet (UVC) light. Food models with various meat contents were made using chopped beef slices and agar solution. Prepared models together with aListeriaselective agar (LSA) plate and a slice of cooked beef were inoculated withL. monocytogenesand then exposed to UVC light. Population ofListeriareduced to below the level of detection on the LSA plates. As the content of beef in the beef-agar models increased, moreL. monocytogenescells survived. Survival was greatest on the treated cooked slice of beef. To better understand the effect of surface irregularities, a white light interferometer was used to analyse the surface smoothness of beef-agar media and LSA plates. No correlation was observed between the surface roughness of seven out of nine types of produced beef-agar media and the degree of inactivation resulting from UVC radiation at the given dose, whereas, less bacterial cells were killed as beef content of the food models increased. The findings of the current study show that the chemical composition of the treated sample also plays an important role in pathogen resistance and survival, meaning that two samples with similar surface irregularities but different chemical composition might produce very different inactivation results when exposed to UVC light.
authors.affiliation: Department of Food Manufacturing and Automation, National Centre for Food Manufacturing, Holbeach Campus, University of Lincoln, Holbeach, PE12 7PT, United Kingdom.
authors.forename: Amir M
authors.initials: AM
authors.lastname: Hamidi-Oskouei
authors.affiliation: Food Refrigeration and Process Engineering Research Centre (FRPERC), Grimsby Institute (GIFHE), Nuns Corner, Grimsby, North East Lincolnshire, DN34 5BQ, United Kingdom.
authors.forename: Christian
authors.initials: C
authors.lastname: James
authors.affiliation: Food Refrigeration and Process Engineering Research Centre (FRPERC), Grimsby Institute (GIFHE), Nuns Corner, Grimsby, North East Lincolnshire, DN34 5BQ, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: James
keywords: Listeria monocytogenes; emerging technology; food model; microbial deactivation; nonthermal decontamination; ready-to-eat beef; shortwave ultraviolet light (UVC); surface analysis; white light interferometer