Inactivation kinetics of Bacillus cereus vegetative cells and spores from different sources by antimicrobial photodynamic treatment (aPDT)
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Universidade Federal de Minas Gerais
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Artigo de periódico
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Antimicrobial photodynamic treatment (aPDT) is a promising alternative to conventional thermal inactivation methods. This study aimed to evaluate Bacillus cereus vegetative cells' inactivation and spores by aPDT with new methylene blue (NMB) as photosensitizer (PS) using red light. The efficacy of aPDT was determined initially by minimal inhibitory concentration (MIC) of NMB at different concentrations and fluences. Cluster analysis from the results of MIC grouped B. cereus strains according to their aPDT susceptibility. Then, four strains (B63, B3, 436, and ATCC 14579) were selected for a survival study of aPDT with NMB in three concentrations (5, 50, and 100 μM). The viability of B. cereus vegetative cells and spores was reduced in all tested fluences. The strain ATCC 14579 (vegetative cells and spores) was the most susceptible to aPDT at relatively low fluence (25 J/cm2). The Weibull model presented a good fit for the inactivation data estimating the kinetic parameters δ (first decimal reduction) and p (shape parameter). This study contributes to the knowledge of the behavior of different strains of B. cereus regarding an emerging method of microbial inactivation. The variability of inactivation among strains will allow the development of more reliable processes.
Abstract
Assunto
Tratamento fotodinâmico antimicrobiano, Células vegetativas, Esporos de Bacillus cereus
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Phenothiazine dye, Spoilage, Pathogen, Nonthermal treatment, Emerging technology
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https://www.sciencedirect.com/science/article/pii/S0023643821001900