Title: Laser etching: A new technology to identify Florida grapefruit Authors
Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 14, 2009
Publication Date: July 8, 2009
Citation: Sood, P., Ference, C., Narciso, J., Exteberria, E. 2009. Laser etching: A novel technology to label Florida grapefruit. HortTechnology. 19(3):504-510. Interpretive Summary: Grapefruit has always been labeled with sticky paper labels mar the fruit, stick to one another in storage and add to the landfill. These labels are easily removed and should there be a problem and the fruit need to be traced back to the grove, the information would be missing. The laser technology uses a CO2 laser beam that etches into the first few outer cells of the fruit peel and leaves a mark containing information that cannot be peeled off, washed off or changed in any way. The information on the label is permanent. Etching into the fruit peel does not increase the entrance of food pathogens, postharvest pathogens or water loss if the laser label is covered with wax after etching. This is a new technology that would benefit Florida citrus growers.
Technical Abstract: Laser labeling of fruits and vegetables is an alternative means to label produce. Low energy CO2 laser beam etches the surface showing the contrasting underlying layer. These etched surfaces can promote water loss and potentially allowing for pathogen entry. The long term effects of laser labeling on produce during storage have not been addressed. Studies were conducted to measure water loss, peel appearance and potential decay in grapefruit (Citrus paradisi) during storage as affected by laser labeling. Laser labeled fruit stored at 10 °C and different relative humidities (i.e. 95% and 65 % RH) for 5 weeks showed no increase in decay compared to control non-etched 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. Furthermore, laser etching of agar plates covered in Penicillium digitatum spores reduced germination at the etched areas. Water loss from etched areas and label appearance were determined during storage. Water loss leveled after one day in storage, whereas appearance slowly deteriorated proportional to laser energy levels and ambient relative humidity. Waxing labeled surface reduced water loss by 73 – 87% depending on ???? was used.