Bacteria and molds may spoil and/or contaminate apple juice either by direct microbial action or indirectly by the uptake of metabolites as off-flavours and toxins. Some of these microorganisms and/or metabolites may remain in the food even after extensive procedures. This study aim to identify the presence of molds (including heat resistant species) and Alicyclobacillus spp., during concentrated apple juice processing. Molds were isolated at different steps and then identified by their macroscopic and microscopic characteristics after cultivation on standard media at 5, 25 and 37°C, during 7 days. Among the 19 isolated found, 63% were identified as Penicillium with 50% belonging to the P. expansum specie. With regards to heat resistant molds, the species Neosartorya fischeri, Byssochlamys fulva and also the genus Eupenicillium sp., Talaromyces sp. and Eurotium sp. were isolated. The thermoacidophilic spore-forming bacteria were identified as A. acidoterrestris by a further investigation based on 16S rRNA sequence similarity. The large contamination found indicates the need for methods to eliminate or prevent the presence of these microorganisms in the processing plants in order to avoid both spoilage of apple juice and toxin production.

The rapid increase in the global production of apples has led to improved monitoring and control of toxic substances present in apples and their derivatives. One of these toxic substances is patulin, a mycotoxin and secondary metabolite produced by different fungi species of the genera Penicillium, Aspergillus, Gymnoascus, Paecilomyces and Byssochlamys. This study evaluated patulin levels in juice produced from Fuji apples subjected to different temperature conditions and storage times in southern Brazil. The apples were divided into groups weighing 1 kg and stored at the following temperatures: 0ºC, 5ºC, 6.7ºC, 19.5ºC and 25ºC. Sub-samples of each group were processed to determine their patulin level by HPLC at the following intervals: 0 (control group), 7, 14 and 21 days. After 28 days of storage at all temperatures, the apples could not be analyzed due to their deterioration. The results indicated that at all temperatures; there was variation in the patulin levels. The smallest patulin value was observed in apple juice stored at 19.5°C and 25°C