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Antimicrobial photodynamic treatment as an alternative approach for Alicyclobacillus acidoterrestris inactivation
- Source :
- Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual), Universidade de São Paulo (USP), instacron:USP
- Publication Year :
- 2020
-
Abstract
- Alicyclobacillus acidoterrestris is a cause of major concern for the orange juice industry due to its thermal and chemical resistance, as well as its spoilage potential. A. acidoterrestris spoilage of orange juice is due to off-flavor taints from guaiacol production and some halophenols. The present study aimed to evaluate the effectiveness of antimicrobial Photodynamic Treatment (aPDT) as an emerging technology to inactivate the spores of A. acidoterrestris. The aPDT efficiency towards A. acidoterrestris was evaluated using as photosensitizers the tetracationic porphyrin (Tetra-Py+-Me) and the phenothiazinium dye new methylene blue (NMB) in combination with white light-emitting diode (LED; 400–740 nm; 65–140 mW/cm2). The spores of A. acidoterrestris were cultured on YSG agar plates (pH 3.7 ± 0.1) at 45 °C for 28 days and submitted to the aPDT with Tetra-Py+-Me and NMB at 10 μM in phosphate-buffered saline (PBS) in combination with white light (140 mW/cm2). The use of Tetra-Py+-Me at 10 μM resulted in a 7.3 ± 0.04 log reduction of the viability of A. acidoterrestris spores. No reductions in the viability of this bacterium were observed with NMB at 10 μM. Then, the aPDT with Tetra-Py+-Me and NMB at 10 μM in orange juice (UHT; pH 3.9; 11°Brix) alone and combined with potassium iodide (KI) was evaluated. The presence of KI was able to potentiate the aPDT process in orange juice, promoting the inactivation of 5 log CFU/mL of A. acidoterrestris spores after 10 h of white light exposition (140 mW/cm2). However, in the absence of KI, both photosensitizers did not promote a significant reduction in the spore viability. The inactivation of A. acidoterrestris spores artificially inoculated in orange peels (105 spores/mL) was also assessed using Tetra-Py+-Me at 10 and 50 μM in the presence and absence of KI in combination with white light (65 mW/cm2). No significant reductions were observed (p
- Subjects :
- Porphyrins
Alicyclobacillus
Light
Food spoilage
Orange (colour)
Microbiology
Agar plate
03 medical and health sciences
chemistry.chemical_compound
Food science
ESPOROS BACTERIANOS
030304 developmental biology
Orange juice
Spores, Bacterial
0303 health sciences
Photosensitizing Agents
030306 microbiology
Chemistry
Guaiacol
New methylene blue
General Medicine
Antimicrobial
Spore
Anti-Bacterial Agents
Fruit and Vegetable Juices
Methylene Blue
Food Science
Citrus sinensis
Subjects
Details
- ISSN :
- 18793460
- Volume :
- 333
- Database :
- OpenAIRE
- Journal :
- International journal of food microbiology
- Accession number :
- edsair.doi.dedup.....eb3de9a79a8602cd3d894be57dd22227