A comparison of sanitizers for fresh-cut mango (Mangifera indica cv. Keitt) was made. Mangos were obtained from a farm in Homestead, Fla., and stored at 15 °C until processed. Before cutting, fruit were dipped in solutions of either sodium hypochlorite (NaOCl) (200 ppm) or peroxyacetic acid (100 ppm). The cut pieces were dipped in acidified sodium chlorite (NaClO2) (200 ppm, pH 2.6) or dilute peroxyacetic acid (50 ppm) for 30 seconds. Resulting cut slices were placed in polystyrene clamshell food containers and stored at 5 °C for 21 days. Samples in the clamshells were tested for changes in microbial stability and for quality parameters every 7 days. Results showed that even though the fruit slices were sanitized after cutting, cut fruit microbial populations were related to the method of whole fruit sanitation. After 15-21 days in storage at 5 °C, cut slices from whole fruit sanitized with peroxyacetic acid that were subsequently treated with dilute peroxyacetic acid or acidified NaClO2 had less contamination [<1 colony-forming unit (cfu) per gram] than samples cut from whole fruit sanitized with NaOCl (<1000 to 3700 cfu/g). These data demonstrate that the method of whole fruit sanitation plays a role in determining the cleanliness of the cut fruit. These sanitizer systems (peroxyacetic acid on whole fruit followed by peroxyacetic acid or acidified NaClO2 on cut slices) effectively reduced microbial growth and kept microbial counts low on cut fruit surfaces for 21 days when compared to cut fruit slices from NaOCl-treated whole fruit.
Laser labeling of fruit and vegetables is an alternative means of labeling produce in which a low-energy carbon dioxide laser beam etches the surface and reveals a contrasting underlying layer. These etched surfaces can promote water loss and may increase the number of entry sites for decay-promoting organisms. The long-term effects of laser labeling on produce quality during storage have not been examined. We conducted experiments to measure water loss, peel appearance, and potential decay in laser-labeled grapefruit (Citrus paradisi) during storage. Laser-labeled fruit stored at 10 °C and two relative humidities (i.e., 95% and 65%) for 5 weeks showed no increase in decay compared with nonetched control fruit, suggesting that laser labeling does not facilitate decay. This was confirmed by experiments where Penicillium digitatum spores were coated on fruit surfaces before and after etching. In either case, no decay was observed. In agar plates containing a lawn of P. digitatum spores, the laser etching reduced germination of spores in contact areas. Water loss from etched areas and label appearance were determined during storage. Water loss from waxed etched surfaces reached control levels after 24 h in storage. Label appearance slowly deteriorated during 4 weeks in storage and was proportional to laser energy levels and ambient relative humidity. Waxing the labeled surface reduced water loss by 35% to 94%, depending on the wax formulation used. We concluded that laser labeling provides the grapefruit industry a safe alternative to adhesive sticker labeling without enhancing decay susceptibility.