a b s t r a c tThe present study evaluated the effect of thermal (temperature) and thermochemical (temperature þ oregano essential oil (EO)) inactivation of Bacillus coagulans spores in Nutrient Broth (NB) adjusted at 4 Brix and pH of 4.2. Thermal treatments included temperatures between 95 and 103 C. For thermochemical treatment, first temperature was fixed at 100 C and EO concentration varied between 250 and 1000 mg/g. Thermochemical treatment significantly reduced the time needed to reduce a 6 log level of spores compared to thermal treatment, for example around 1.4 min with 400 mg/g of EO. Then, EO concentration was fixed at 400 mg/g and temperature varied between 90 and 100 C. Although the first results showed a faster spore reduction with 500 mg/g, the fixed EO concentration was 400 mg/g, since it represents a lower organoleptic impact and also a significant reduction in the spores' resistance.For instance, at 97 C and 400 mg/g, about 4.3 min was needed to reduce the spores in 6 log, without the EO this time was 5.0 min. These findings indicate that oregano EO may be used to render B. coagulans spores more susceptible to the lethal effect of heat.

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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.

). Os ascósporos destes fungos podem permanecer em estado de dormência em restos de frutas apodrecidas e no solo ( RAJASHEKHARA; SURESH; ETHIRAJ, 2000;TOURNAS;TRAXLER, 1994), necessitando ativação térmica para germinarem, o que normalmente corresponde aos processamentos térmicos comerciais aplicados a produtos de frutas (ENIGL; KING Jr.; TOROK, 1993).Estes microrganismos ainda são conhecidos por produzirem várias micotoxinas, como a patulina, durante seu desenvolvimento nos produtos de frutas, o que representa um grave AbstractHeat resistant molds are able to survive the pasteurization process applied to apple products. This study aimed at detecting and identifying heat resistant molds during the processing of apple nectar (pH 3.4; 11.6 °Brix) in order to select the most heat resistant mold. The isolation was carried out after heat shock at 70 °C, during 2 hours, and incubation at 30 °C, in PDA (3% agar), where rose bengal was added. The identification of macro and microscopic structures was carried out after incubation in three different media (G25N, CYA, MEA) and temperatures. Different heat shocks, from 80 °C/20 minutes to 97 °C/15 minutes, were applied to select the most heat resistant mold. Eleven strains were selected, of which five were heat-resistant: three strains were isolated from apple and concentrated apple juice and were identified as Neosartorya fischeri; one strain, isolated from apple, was identified as Byssochlamys fulva and one strain, isolated from the product after the first pasteurization, was identified as Eupenicillium sp. The most heat-resistant strains belong to N. fischeri and B. fulva, which were able to survive at 95 °C/20 minutes. Among the six remaining, one was identified as Aspergillus sp., however, none of them was heat resistant. Keywords: heat resistant molds; N. fischeri; B. fulva; apple nectar. ResumoOs fungos filamentosos termorresistentes são capazes de sobreviver aos processos de pasteurização aplicados aos produtos de frutas. Este estudo visou isolar e identificar fungos termorresistentes durante o processamento de néctar de maçã (pH 3,4 e 11,6 °Brix), de forma a selecionar o bolor mais termorresistente. O isolamento foi obtido após choque térmico de 70 °C/2 horas e incubação a 30 °C em PDA (3% de ágar) acrescido de rosa de bengala. A identificação foi baseada na morfologia e nas estruturas micro e macroscópicas observadas após incubação das cepas em três diferentes meios (G25N, CYA e MEA) e temperaturas. O fungo mais termorresistente foi selecionado pela aplicação de choques térmicos (de 80 °C/20 minutos até 97 °C/15 minutos). Foram detectadas 11 linhagens de bolores, sendo 5 termorresistentes. Dentre estas, três cepas, isoladas da matéria-prima e do concentrado de maçã, foram identificadas como Neosartorya fischeri; uma cepa isolada da matéria-prima foi identificada como Byssochlamys fulva, e uma cepa isolada do produto após a primeira pasteurização foi identificada como Eupenicillium sp. As cepas mais resistentes foram as de N. fischeri e B. fulva, que sobreviveram ao...