Issue link: https://read.dmtmag.com/i/616629
www.goodfruit.com GOOD FRUIT GROWER JANUARY 1, 2016 29 building a line, to consider that, and it doesn't cost a lot of money to do it. Just a little alteration makes a huge difference for food safety. "If you have two separate water systems, a dump tank followed by a separate flume system, you can switch the water in the first dump tank very frequently. You don't have to dump all the water in the system at one time. It's easy to replenish that tank and keep it clean. Determining an appropriate water change schedule with more frequent water changes can improve safety." The oxidation/reduction potential (ORP) can be used as an indicator of how much active chlorine is in the system to help control microbes, so it's important to measure the ORP with a meter or probe to make sure it stays in the right range, she said. However, readings can be affected by the placement and accuracy of the instrument as well as frequency of calibration. For example, if readings are taken close to the chlorine injection system, perhaps because it's a convenient location, they might not accurately indicate the overall ORP level throughout the entire system. The scientists recommend aiming for ORP readings higher than the minimum target levels to control microbes to account for variability in readings and the accuracy of the probes. Meters need to be maintained properly. Spray bars A spray bar system can be an effective way to reduce the microbial load on fruit. However, Hanrahan said many packing lines don't have a spray bar or, if they do, it's not long enough. "If you have a spray bar that applies a treatment directly to the fruit for a few seconds, that's clearly too short." Research has shown that generic (non-pathogenic) Escherichia coli on apples can be reduced by more than 90 percent when 60 to 80 parts per million of peroxy- acetic acid are directly applied to the fruit for at least 30 seconds, with or without soap. Some packers have changed the layout of their pack- ing lines to add spray bars or created space for longer spray bars. "This is a nice outcome, so you can get microbial reductions on the packing line," Hanrahan said. The scientists emphasize that microbial control must be maintained throughout the packing process. In a study at a cooperating packing house, they found no evi- dence of coliforms or generic E. coli in the pre-size dump tank water system, but the lack of a sanitizer in the flume system and bin fillers resulted in increasing microbial loads on fruit after pre-sizing. They also monitored microbe levels after each step during final packing: dump tank, soap spray bar, hyper- wash, water rinse spray bar, fans, wax application and dryer. The step that appeared to reduce microbes the most was drying. Research is now underway to further study how dry- ing during the packing process affects microorganisms on fruit. Overall, progress is being made on identifying steps in a packing system that can improve microbial control and offer opportunities for microbial reduction, Killinger and Hanrahan report. • "Determining an appropriate water change schedule with more frequent water changes can improve safety." —Ines Hanrahan 1-800-421-4001 Phone: 503-538-2131 Fax: 503-538-7616 info@treeconnect.com • www.treeconnect.com 1-800-421-4001 Phone: 503-538-2131 Fax: 503-538-7616 info@treeconnect.com • www.treeconnect.com • Aztec Fuji® cv. DT2 • Firestorm®Honeycrisp™ USPP 7,197 • Buckeye® Gala USPP 10,840 • Pink Lady® Brand cv. Cripps Pink • NEW pollenizers & more! 2017 TREES AVAILABLE Call Tree Connection today! RESERVE YOUR TREES!