UNIVERSIDADE FEDERAL DE SANTA CATARINA CENTRO TECNOLÓGICO PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA DE ALIMENTOS

The majority of concentrated apple juice produced in Brazil (>90%) is destined for exportation. Apples rejected for the fresh fruit consumption market are used for juice processing. The quality of this raw material should be attained in order to obtain a juice under the rigid international standards. Heat resistant molds and the thermoacidophilic bacterium from Alicyclobacillus genus are among the microorganisms of importance for heat-processed fruit juices, such as apple juice. Some species of heat resistant molds, such as Byssochlamys spp. , are able both to deteriorate packaged fruit juice and to produce mycotoxins. Alicyclobacillus causes medicinal off-flavors in packaged fruit juices. Penicillium expansum is the most important contaminant in apples and is responsible for “blue mold rot” in those fruits. Patulin (PAT) is a thermal stable mycotoxin produced primarily by this mold and also by Byssochlamys spp. PAT has been shown to exhibit severe chronic and acute effects in humans. The regulatory agencies have recommended a PAT maximum level of 50 μg/L (ppb) for apple juice. Then, the aim of this study was to detect PAT in apples and to assess the washing/sanitizing treatments for apples destined for juice. In the initial survey, P. expansum, Byssochlamys fulva and Alicyclobacillus acidoterrestris was the most import microorganisms in the process. In the disinfection test, the chlorine-based sanitizer sodium dichloroisocyanurate was more efficient than peracetic acid against P. expansum spores. None of those sanitizers were efficient against A. acidoterrestris and B. fulva spores. When sodium hypochlorite was tested against P.expansum, the efficacy of chlorine solutions was enhanced by decreasing the pH. For the modeling investigation, the results showed that Bigelow and Weibull were the best models to describe P. expansum thermal and sanitizer inactivation, respectivelly. All P. expansum inoculated apple varieties incubated under 11°C and 20.5°C showed mold spoilage at both temperatures, except Red Delicious and Empire. The highest PAT productions occurred in Golden Supreme and McIntosh varieties. Findings showed that PAT was not detected throughout the harvest season. However, 86% of lots from offseason yielded more than 50 ppb of PAT. The sampling plan developed to evaluate the apples during the receiving step suggested to reject the lot when more than 8 rotten fruits were found in a total of 50 apples, because the risk of > 50 ppb of PAT in the final product. Rotten fruits are those with size lesion > 4 cm or with visible “blue mold” development. Wash treatments using high-pressured water reduced PAT levels by 64 to 100%, but the toxin was transferred to the water. Treatments using sodium dichloroisocyanurate proved to be efficient in reducing 100% of PAT in aqueous solution. In conclusion, this sanitizer, even at low concentration (25 ppm), is efficient to reduce both PAT and P. expansum spores and should be recommended for apple handling and washing treatments. This investigation provides direct impact in the PAT levels for the final product which reduce the risk for healthy consumers and help in the development of industry international competitiveness.