Improving the Microbiological Safety of Candy Apples and Shredded Lettuce Through Applying Sequential Intervention Steps
The following reports on the efficacy of sequential treatments to decontaminate fresh produce using candy apples and shredded lettuce as model systems. A forced air ozone treatment was developed to treat whole apples and lettuce heads. By using a combination of laboratory and pilot scale studies, the treatment time, air flow and ozone concentration was optimized to support a 1.90-2.40 log CFU of target bacteria. A further process based on advanced oxidation process (AOP) was developed using a combination of UV-C, hydrogen peroxide and ozone generated by a lamp emitting at a wavelength of 174nm. From optimization studies it was found that using a combination of UV-C and 6% hydrogen peroxide reduced Listeria monocytogenes by 0.86 log CFU. By using a combination of treatments it was possible to achieve a >5 log cfu reduction of target pathogens. The technologies developed during this study provides preventive controls that can be applied in post-harvest fresh produce processing.