Potential of UV-C illumination for Reducing Microbial Pathogens in Fresh-cut Avocado

Consumption of fresh-cut fruit has increased in the last years. This type of product is more susceptible to microbial contamination than entire fruit, for this reason, disinfection is a very important step in fresh-cut processing. Chlorine is the most common disinfectant in fresh-cut industry, but due to environmental and health risks there is a demand to develop new sanitizers. Shortwave ultraviolet light (UV-C) could be a safe and economical alternative sanitizing method for fresh-cut industry, since it is known that UV-C light causes severe microbial DNA damage being used as disinfectant technique in other fields. The aim of this work was to evaluate the effect of UV-C light on reducing microbial contamination of foodborne pathogens on fresh-cut avocado. Fresh-cut avocados were inoculated with a suspension of Escherichia coli, Listeria innocua or Salmonella spp. at 107 CFU/ml and treated with different doses of UV-C light (0.5, 1.0 and 3.0 kJ/m2). Controls consisted in inoculated fresh-cut avocados (i) untreated and (ii) treated with a high dose of sodium hypochlorite solution (200 mg/L,) for 3 min at 150 rpm and rinsed twice with cold distilled water for 3 min at 150 rpm. Doses of 1.0 and 3.0 kJ/m2 were the treatments with more effective bactericidal activity. These doses allowed a population reduction of L. innocua and Salmonella higher than 5.0 log units (below detection limit) and E. coli from 2.0 to 3.5 log units. Sodium hypochlorite reduced Salmonella spp. to the same extend as the UV-C treatments, but population reductions of E. coli and L. innocua obtained by sodium hypochlorite washing were significantly lower than reductions obtained by UV-C illumination at 1.0 and 3.0 kJ/m2. UV-C treatment may be an alternative to reduce the use of chlorine in fresh-cut fruit industry. Complete list of authors:C. Nunes(1)*, A. Gra?a(1), M. Salazar(2), M. Abadias(3), J. Usall(3) (1)ICAAM-Universidade do Algarve. FCT. Ed 8. Campus de Gambelas. 8005-139 Faro, Portugal (2)CICAE. Instituto Universit?rio Dom Afonso III. INUAF. 8100-718 Loul?.Portugal(3)IRTA. Centre UdL-IRTA. XaRTA-Poscollita. Av. Rovira Roure, 191. 25198. Lleida. Catalonia, Spain *canunes@ualg.pt? ? Source:II ISHS International Conference on Quality Management of Fresh Cut Produce: Convenience Food for a Tasteful Life 17-21 July 2011, Turin - Italy http://www.freshcut2011.org/downloads/Freshcut2011_Book_of_Abstracts.pdfSource of the image:INGEMAQ, manufacturer of machinery for advocado processing, and other produce