Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2015
Publication Date: 7/11/2015
Citation: Lacombe, A.C., Niemira, B.A., Boyd, G., Sites, J.E., Gurtler, J., Tyrell, B.K., Fleck, M.A. 2015. Inhibition of enteric pathogens using integrated high intensity 405 nm LED on the surface of almonds. Meeting Abstract. IFT Annual Meeting. Chicago, Illinois. July 11-14, 2015.Volume 1, Page 1.
Technical Abstract: The disinfecting properties of 405 nm light were investigated against Escherichia coli O157:H7, Salmonella, and their non-pathogenic surrogates inoculated onto the surface of almonds. High intensity monochromatic light was generated from an array of narrow-band 405 nm light emitting diodes (LED). Almonds were inoculated with high and low level (8 or 5 CFU/g) E.coli O157:H7 and pathogenic Salmonella, as well as the non-pathogenic surrogates E.coli K-12 and an avirulent strain of Salmonella Typhimurium. Inoculated almonds were treated with 405 nm light for 0, 60, 120, 240, 360, 480, and 600 sec at a working distance of 7 cm. Simultaneous to treatment, cooling air was directed onto the almonds at a rate of 4 cfm, sourced through a container of dry ice. An infra-red camera was used to monitor the temperature readings after each run. E.Coli/Coliform Petrifilm was used to enumerate surviving E.coli (pathogen or surrogate), and the Petrifilm Aerobic Count Plate was used for Salmonella. High intensity 405 nm light yielded significant log reduction (1 log CFU/g) against E.coli at 480 seconds. Salmonella was reduced by 0.5 log CFU/ml at 600 seconds. These reductions were obtained for both pathogens and both surrogates, regardless of the initial inoculum. The maximum temperature reached during treatment was 25 degrees C, confirming the nonthermal nature of the process. Photo-biological technology that utilizes the bactericidal properties of high intensity monochromatic light may also have potential applications in other areas including the food industry sector, and the results of this study demonstrate the sensitivity of the significant foodborne pathogen, E. coli O157:H7 and its surrogate E. coli K-12. This zero-contact, nonthermal technology can be used by producers of low moisture foods to ensure postharvest food safety.