Survey of molds, yeast and Alicyclobacillus spp. from a concentrated apple juice productive process

Abstract

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.

Characterization of Osmotolerant Yeasts and Yeast‐Like Molds from Apple Orchards and Apple Juice Processing Plants in China and Investigation of Their Spoilage Potential

“…In case of the processing plant environment, osmotolerant isolates were present in all samples except in the online apple juice concentrate. This result is consistent with previous reports suggesting that the distribution of yeasts in orchard and processing plant environments was widespread (Sabate and others ; Vadkertiová and others ; Salomão and others ). The highest numbers of osmotolerant isolates (twenty isolates) were recovered from the air in both plants (Table ).…”

“…A possible explanation for this result might be that osmotolerant isolates in the extracted apple juice were not totally inactivated by the first pasteurization (96 °C, 30 s) and these residual isolates survived in the production line until the second concentration stage (80 to 85 °C, 3 min) in the LC plant. Similar to our findings, Salomão and others () also reported that yeasts were recovered from the stages before concentration during apple juice processing. All online concentrate tested negative for osmotolerant isolates whereas the concentrate that had been stored for a longer time without clear indications of spoilage contained osmotolerant isolates (Table ).…”

Inactivation of Byssochlamys nivea ascospores in strawberry puree by high pressure, power ultrasound and thermal processing

“…Temperature time combinations of 87.5°C-10 min and 90°C-2 min did not kill B. nivea in processed canned fruits (Luthi and Hochstrasser, 1952;Put and Kruiswijk, 1964). Other investigators also reported the isolation of B. nivea from pasteurized fruit concentrates (Palou et al, 1998;Salomão et al, 2014). Milk and milk products (Engel and Teuber, 1991), cucumber brine (Yates and Ferguson, 1963), cream cheese (Pitt and Hocking, 1997) and palm wine (Eziashi et al, 2010) have also been contaminated by this species.…”

Comparison and storage study of ultra-filtered clarified jamun (Syzygium cumini) juice

“…The values increased with increase in storage period for all the juices. Salomão et al (2014) also found yeast and mold count of untreated apple juice to be of the order of 10 5 log CFU/ml and the value decreased with enzymatic treatment and ultrafiltration.…”