The effects of pulsed light (PL) treatments combined with a quality-stabilizing dip on the quality and antioxidant attributes of fresh-cut 'Golden delicious' apples was studied. Apple wedges were dipped into a solution of 1% w/v N-acetylcysteine and 0.5% w/v CaCl 2 and flashed with broad-spectrum light with an overall radiant exposure of 4, 8, 12 and 16 J. cm-2. General microbial counts, color, firmness, phenolic compounds and vitamin C contents were evaluated over 15 days at 5 ºC. More pronounced reductions of the naturallyoccurring microbiota were observed as the applied PL-dose increased. The qualitystabilizing pre-treatment effectively prevented browning phenomena on the cut-tissue surface. In addition, browning and oxidation were not promoted in PL flashed samples. Indeed, the initial contents in phenolic compounds and vitamin C were even better maintained than in untreated samples. Treatments of 8 and 16 J cm-2 were most effective for maintaining the quality and antioxidant characteristics.

Fresh-cut strawberries may be sold as a highly convenient, healthy and fully edible product. However, processing and packaging conditions need to ensure the maintenance of their quality characteristics and content of bioactive compounds. This study provides scientific evidence regarding the beneficial effects of pulsed light treatments combined with a quality-stabilizing dip for extending the shelf-life of fresh-cut fruit. These combined treatments may be economically viable at industrial level because of their low energy requirements and reduced treatment time.

The influence of a selection of minimal processing techniques (sanitizing wash prior to packaging, modified atmosphere, storage conditions under light or in the dark) was investigated in relation to the survival of, attachment to and internalization of enteric pathogens in fresh produce. Cut Iceberg lettuce was chosen as a model for fresh produce, Escherichia coli O157:H7 (E. coli O157) and Salmonella enterica were chosen as pathogen models. Care was taken to simulate industrial post-harvest processing. A total of 50 ± 0.1 g of fresh-cut Iceberg lettuce was packed in bags under near ambient atmospheric air with approximately 21% O 2 (NAA) conditions or equilibrium modified atmosphere with 3% O 2 (EMAP). Two lettuce pieces inoculated with E. coli O157 BRMSID 188 or Salmonella Typhimurium labeled with green fluorescent protein (GFP) were added to each package. The bags with cut lettuce were stored under either dark or light conditions for 2 days at 7°C. The pathogens' capacity to attach to the lettuce surface and cut edge was evaluated 2 days after inoculation using conventional plating technique and the internalization of the bacteria was investigated and quantified using confocal microscopy. The effect of a sanitizing wash step (40 mg/L NaClO or 40 mg/L peracetic acid + 1143 mg/L lactic acid) of the cut lettuce prior to packaging was evaluated as well. Our results indicate that both pathogens behaved similarly under the investigated conditions. Pathogen growth was not observed, nor was there any substantial influence of the investigated atmospheric conditions or light/dark storage conditions on their attachment/internalization. The pathogens attached to and internalized via cut edges and wounds, from which they were able to penetrate into the parenchyma. Internalization through the stomata into the parenchyma was not observed, although some bacteria were found in the substomatal cavity. Washing the cut edges with sanitizing agents to reduce enteric pathogen numbers was not more effective than a rinse with precooled tap water prior to packaging. Our results confirm that cut surfaces are the main risk for postharvest attachment and internalization of E. coli O157 and Salmonella during minimal processing and that storage and packaging conditions have no important effect.

The effects of UV-C treatment (5.8 kJ m −2) alone and combined with the addition of orange juice on the bioactive properties, microbiological, and sensory quality of fresh-cut strawberries for 12 days at 0°C were studied. During storage, the contents of ascorbic acid (AA), total phenols, flavonoids, and anthocyanins were enhanced in strawberry slices only treated with UV-C (UV slices), whereas ellagic acid slightly decreased in correlation with the antioxidant capacity. After 12 days of storage, AA level in UV slices was 10% higher than those in the other samples studied. In addition, UV slices showed higher contents of phenols (about 14%), flavonoids (about 23%), and anthocyanins (11-41%) than untreated slices during storage. However, fresh-cut strawberries UV-C treated and immersed in juice showed slight but significant AA decrease due to its oxidation to dehydroascorbic acid. Also, phenolic compounds decreased that was associated with their diffusion to the juice and correlated with the antioxidant capacity. Although both UV-C treatments alone and combined with juice immersion reduced microbial load, UV-C applied alone allowed obtaining the highest microbial reductions. After 8 days of storage, the most significant reductions were found, 1.4 log units for mesophilic bacteria and 1.3 log units for molds and yeasts. In addition, UV-C applied alone allowed maintaining firmness and obtaining a product with the best sensory quality throughout storage. Hence, the irradiation at 5.8 kJ m −2 applied alone was the most effective preserving treatment and may be useful to obtain a value-added product.