UV-C irradiation reduces microbial populations and deterioration in Cucurbita pepo fruit tissue

Effectiveness of two-sided UV-C treatments in inhibiting natural microflora and extending the shelf-life of minimally processed ‘Red Oak Leaf’ lettuce

“…However, no significant differences were found among various treatments (1.18-7.11 kJ m À2 ) in this study. Similar findings were reported from Erkan et al (2001) on zucchini squash tissue. In fruit that involve the ripening process (e.g.…”

“…Allende and Artes (2003a, b) found similar results when minimally processed 'Lollo Rosso' and 'Red Oak Leaf' lettuces were treated with 0.4, 0.81, 2.44, 4.07, and 8.14 kJ m À2 on only one side of the tissue. Erkan et al (2001) found that the mesophilic bacterial populations of squash slices were higher in non-radiated controls than in those treated with 0.493 or 9.80 kJ m À2 UV-C radiation. Therefore, UV-C radiation prolonged shelflife of fresh-cut lettuce based on total microbial counts.…”

“…Additionally, Maharaj et al (1999) found that increases in CO 2 production in fresh tomato after UV-C radiation were proportional to the applied dose. Erkan et al (2001) reported that the respiration rates of squash slices were higher in radiated tissue than those of non-radiated controls, and the increase in the respiration rate correlated with the increase in UV-C intensity. However, Vicente et al (2005) found that UV-C treated peppers displayed a lower respiration rate than untreated control fruit.…”

“…Taking this limit into account, the shelf-life of the product was 1 day longer when 1.18 kJ m À2 was applied and 3 days longer when the highest UV-C dose was applied. It was reported that yeast growth in squash slices decreased at least 2 or 3 log units when treated with 4.9 and 9.86 kJ m À2 UV-C doses (Erkan et al, 2001). Ultraviolet radiation causes crosslinks of aromatic amino acids at their carbon-carbon double bonds which lead to membrane depolarization and abnormal ionic flow (Moseley, 1990), photochemical oxidation (Braun and Oliveros, 1997) and pyrimidine dimer formation in DNA strands (Miller et al, 1999).…”

“…Of special interest is the development of an UV-C apparatus, which delivered low-dose UV-C light to the surface of fruit on a processing line (Wilson et al, 1997). However, only a few studies have focused on UV-C radiation of minimally processed fruit and vegetables (Allende and Artes, 2003a, b;Erkan et al, 2001) and all of them radiated the product only on one side of the tissue. The overall objective of this study was to determine the efficiency of three UV-C radiation doses on the in vitro growth of different vegetable-associated micro-organisms and the microbial reduction of the resident microflora of fresh processed 'Red Oak Leaf' lettuce when applied to both sides of the tissue.…”