IAFP 2009 Program Book and Abstract Book - AB161

to the sanitizers. The 100 ppm Cl with 5% acetic acid was more effective in microbial reduction during 10 days of storage, however, the lowest sensory scores of color, flavor, texture and overall acceptability were observed in sample washed with 100 ppm Cl with 5% acetic acid, regardless of the type of produce after 10 days. Significance: Washing with 100 ppm Cl with 5% acetic acid can be recommended as an effective means of enhancing the safety of fresh produce. However, it is inappropriate for produce kept in refrigeration for more than 5 days. P3-35 Reduction of Pathogenic Bacteria on Avocados by Washing Treatments OFELIA M. RODRIGUEZ-GARCIA, Marisela García-Bernal, Porfirio Gutiérrez-González, Liliana Martínez-Chávez and Cristina Martínez-Cárdenas Universidad de Guadalajara, Farmacobiologia, Guadalajara, South Introduction: The potential for superficial contamination of avocados by pathogenic bacteria has recently been established. In fact, most of the plants that process guacamole and minimally processed avocado in Mexico are encouraged to apply a surface decontamination treatment prior to processing. Although various chemical sanitizers are commercially available, validation studies to prove their efficacy are lacking. Purpose: The purpose of this study was to compare the efficacy of different washing procedures at reducing Listeria monocytogenes, Salmonella and Escherichia coli O157:H7 on the surface of avocados. Methods: Fresh avocados (Hass) were inoculated with a bacterial cocktail containing rifampicin resistant (Rif +) L. monocytogenes or Rif + Salmonella and E. coli O157:H7, and then subjected to washing with: tap water, hot water (70°C), lactic acid (2%, 55°C), peracetic acid (80 ppm), chlorine (200 ppm) or a commercial formulation based on natural substances. After treatment, reductions in population were determined by plate counting and physical determinations, as weight, texture, firmness and skin color, were performed. Results: Hot water and lactic acid treatments produced the greatest reductions of the 3 pathogenic bacteria (2.6 – 3.4 log/ avocado). The reductions obtained by peracetic acid, chlorine or the commercial formulation (< 2 log/avocado) were not different from the reductions obtained by a sole tap water wash. None of the treatments affected weight, texture, firmness or skin color of the fruits. Significance: Lactic acid and hot water treatments reduced L. monocytogenes, Salmonella and E. coli O157:H7 by ~3 log cycles on Hass avocados without affecting the fruit quality. Reduction with hot water may have an advantage over treatment with lactic acid by leaving no chemical residues on the fruit. P3-36 The Effect of Gaseous Ozone on the Shelf Life and Sensory Properties of Fresh Lychees LOUISE FIELDING, Rebecca Brown and Arthur Tatham UWIC, Cardiff School of Health Sciences, Cardiff, United Kingdom Introduction: The post-harvest spoilage of fresh produce is of global economic importance. Spoilage is often controlled by fungicides such as imazalil and thiabendazole, but microbial resistance and human health risks have led to an increased demand for alternative technologies. Exposure to gaseous ozone on post harvest decay of different commodities during storage has been found to inhibit aerial mycelia and prevent sporulation of mold spores. Purpose: This study investigated the effect of gaseous ozone on the shelf life of fresh lychees (Litchi chinensis Sonn.). Microbiological and sensory quality parameters (appearance and texture) were investigated. Methods: Seventy crates, each containing 2 kg of lychees, were stacked 10 crates high and treated with gaseous ozone for 2 h at a concentration of approximately 24 ppm in a Biosafety level 2 bioaerosol test chamber. The fruit was then packed into trays and over-wrapped to mimic the conditions prevalent during subsequent distribution and retail storage. Control samples were also prepared, which were not subjected to ozone treatment, but wrapped and stored in an identical manner. The level of fungal contamination of the pedicarp was analyzed using surface plate count. The color of the pedicarp was analyzed visually and the texture of the pedicarp and fruit (penetration and withdrawal forces) was measured using a Penetrometer. Results: There was a significant difference (P ≤ 0.05) between mold counts on ozonated and non-ozonated (control) lychees. A visual assessment after 15 days showed this marked difference. There was a significant difference (P ≤ 0.05) between the top crates compared with crates taken from middle and bottom portion of the stack, with those at the top showing lower mold counts. There was, however, no significant difference between the middle and bottom crates. There were no significant differences in color (pedicarp only) or texture (pedicarp and flesh) of ozonated and control fruit. The effect of ozone on the texture showed a softening of the pedicarp but no significant differences in softness or ‘stickiness’ of the fruit. Significance: These results suggest that the application of gaseous ozone to fresh lychees can increase shelf life by 4 days. This is dependent on the position of the crates during treatment, as the ozone must be allowed to circulate freely around the produce. Gaseous ozone treatment for the prevention of post harvest decay and the extension of the shelf life of produce has the potential for application within the food industry. P3-37 Fate of Salmonella spp. on Fresh and Frozen Cut Mangoes DSC LAURA K. STRAWN and Michelle D. Danyluk University of Florida, Food Science and Human Nutrition, Lake Alfred, FL, USA Introduction: Imported raw mangoes have been associated with three US outbreaks of Salmonella. Purpose: Our objective was to evaluate the fate of Salmonella on fresh (23, 12 and 4°C) and frozen (-20°C) cut mangoes. Methods: Cut mangoes were spot inoculated with a five strain cocktail of Salmonella at 5 log CFU/g (-20 ± 2°C) or 1, 3 and 5 log CFU/g (all other temperatures). Samples were enumerated following stomaching on selective and non-selective media at days 0, 1, 3, 5 and 7 (23 ± 2°C); 0, 1, 3, 5, 7, 10, 14, 21 and 28 (12 ± 2 and 4 ± 2°C); and 0, 7, 14, 21, 28, 60, 90 and 120 (-20 ± 2°C). Population levels in log CFU/g were calculated. Abstract Book — 161 Poster

IAFP 2009 Program Book and Abstract Book

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