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Tarrah A, Pakroo S, Carlot M, Nesto C, Cirillo A, Lombardi A, Corich V, Giacomini A. Thermal resistance and high-performance microwave decontamination assessment of Bacillus endospores isolated from food-grade herbal extracts. PLoS One 2021; 16:e0261988. [PMID: 34962973 PMCID: PMC8714112 DOI: 10.1371/journal.pone.0261988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/14/2021] [Indexed: 11/18/2022] Open
Abstract
Generally, endospore contamination can occur from different sources during product manufacturing in many industries and therefore lower its quality by affecting physicochemical properties and shelf-life. Bacterial endospores can germinate inside the product and produce several enzymes, which can cause several undesirable changes. This study assessed the spores thermal resistance and applied a microwave decontamination technique toward herbal extracts (Tilia tomentosa and Centella asiatica) containing ethanol or glycerol. Based on 16S rRNA analysis, the detected contaminant endospores belonged to different Bacillus species, namely B. subtilis, B. zhangzhouensis, and B. pumilus. The thermal resistance assessment using inoculated endospores in the actual products revealed B. pumilus T2 as the most resistant endospore to the heat treatments tested in both T. tomentosa and C. asiatica extracts. Finally, a high-performance microwave technique was used to decontaminate T. tomentosa extract against the mixture of Bacillus spores. Results from the microwave technique indicate that the increase of temperature from 100°C to 105°C not only decontaminated the product but also could dramatically decrease the effective thermal treatment time (10 times), which can benefit the product quality. The results provided in this study considerably contribute to improving an original decontamination method for products containing glycerol and ethanol with the most negligible effect on product quality.
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Affiliation(s)
- Armin Tarrah
- Department of Agronomy Food Natural Resources Animal and Environment (DAFNAE), University of Padova, Legnaro, PD, Italy
| | - Shadi Pakroo
- Department of Agronomy Food Natural Resources Animal and Environment (DAFNAE), University of Padova, Legnaro, PD, Italy
| | - Milena Carlot
- Interdepartmental Centre for Research in Viticulture and Enology (CIRVE), University of Padova, Conegliano, TV, Italy
| | - Camilla Nesto
- Agripharma Società Cooperativa Agricola via Prima Strada 11, Vescovana, PD, Italy
| | - Antonella Cirillo
- Agripharma Società Cooperativa Agricola via Prima Strada 11, Vescovana, PD, Italy
| | - Angiolella Lombardi
- Department of Agronomy Food Natural Resources Animal and Environment (DAFNAE), University of Padova, Legnaro, PD, Italy
| | - Viviana Corich
- Department of Agronomy Food Natural Resources Animal and Environment (DAFNAE), University of Padova, Legnaro, PD, Italy
- Interdepartmental Centre for Research in Viticulture and Enology (CIRVE), University of Padova, Conegliano, TV, Italy
- * E-mail:
| | - Alessio Giacomini
- Department of Agronomy Food Natural Resources Animal and Environment (DAFNAE), University of Padova, Legnaro, PD, Italy
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Gonzalez LE, Szalwinski LJ, Marsh BM, Wells JM, Cooks RG. Immediate and sensitive detection of sporulated Bacillus subtilis by microwave release and tandem mass spectrometry of dipicolinic acid. Analyst 2021; 146:7104-7108. [PMID: 34757350 DOI: 10.1039/d1an01796a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Spore lysis of Bacillus species is achieved by brief (1 min) microwave irradiation while tandem mass spectrometry (MS/MS) allows identification of the characteristic spore marker, dipicolinic acid. This rapid measurement, made on 105-108 spores, has significant implications for biothreat recognition.
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Affiliation(s)
- L Edwin Gonzalez
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
| | - Lucas J Szalwinski
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
| | - Brett M Marsh
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
| | | | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
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Eijlander RT, Holsappel S, de Jong A, Ghosh A, Christie G, Kuipers OP. SpoVT: From Fine-Tuning Regulator in Bacillus subtilis to Essential Sporulation Protein in Bacillus cereus. Front Microbiol 2016; 7:1607. [PMID: 27790204 PMCID: PMC5061766 DOI: 10.3389/fmicb.2016.01607] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/26/2016] [Indexed: 12/14/2022] Open
Abstract
Sporulation is a highly sophisticated developmental process adopted by most Bacilli as a survival strategy to withstand extreme conditions that normally do not support microbial growth. A complicated regulatory cascade, divided into various stages and taking place in two different compartments of the cell, involves a number of primary and secondary regulator proteins that drive gene expression directed toward the formation and maturation of an endospore. Such regulator proteins are highly conserved among various spore formers. Despite this conservation, both regulatory and phenotypic differences are observed between different species of spore forming bacteria. In this study, we demonstrate that deletion of the regulatory sporulation protein SpoVT results in a severe sporulation defect in Bacillus cereus, whereas this is not observed in Bacillus subtilis. Although spores are initially formed, the process is stalled at a later stage in development, followed by lysis of the forespore and the mother cell. A transcriptomic investigation of B. cereus ΔspoVT shows upregulation of genes involved in germination, potentially leading to premature lysis of prespores formed. Additionally, extreme variation in the expression of species-specific genes of unknown function was observed. Introduction of the B. subtilis SpoVT protein could partly restore the sporulation defect in the B. cereus spoVT mutant strain. The difference in phenotype is thus more than likely explained by differences in promoter targets rather than differences in mode of action of the conserved SpoVT regulator protein. This study stresses that evolutionary variances in regulon members of sporulation regulators can have profound effects on the spore developmental process and that mere protein homology is not a foolproof predictor of similar phenotypes.
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Affiliation(s)
- Robyn T Eijlander
- Top Institute Food and NutritionWageningen, Netherlands; Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
| | - Siger Holsappel
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen Groningen, Netherlands
| | - Anne de Jong
- Top Institute Food and NutritionWageningen, Netherlands; Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
| | - Abhinaba Ghosh
- Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge Cambridge, UK
| | - Graham Christie
- Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge Cambridge, UK
| | - Oscar P Kuipers
- Top Institute Food and NutritionWageningen, Netherlands; Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
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Inactivation of Clostridium difficile spores by microwave irradiation. Anaerobe 2015; 38:14-20. [PMID: 26546732 DOI: 10.1016/j.anaerobe.2015.10.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/25/2015] [Accepted: 10/30/2015] [Indexed: 02/06/2023]
Abstract
Spores are a potent agent for Clostridium difficile transmission. Therefore, factors inhibiting spores have been of continued interest. In the present study, we investigated the influence of microwave irradiation in addition to conductive heating for C. difficile spore inactivation in aqueous suspension. The spores of 15 C. difficile isolates from different host origins were exposed to conductive heating and microwave irradiation. The complete inhibition of spore viability at 10(7) CFU/ml was encountered following microwave treatment at 800 W for 60 s, but was not observed in the conductive-heated spores at the same time-temperature exposure. The distinct patterns of ultrastructural alterations following microwave and conductive heat treatment were observed and the degree of damages by microwave was in the exposure time-dependent manner. Microwave would therefore be a simple and time-efficient tool to inactivate C. difficile spores, thus reducing the risk of C. difficile transmission.
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Tola YB, Ramaswamy HS. Thermal destruction kinetics of Bacillus licheniformis spores in carrot juice extract as influenced by pH, type of acidifying agent and heating method. Lebensm Wiss Technol 2014. [DOI: 10.1016/j.lwt.2013.09.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Kim SY, Shin S, Song CH, Jo EK, Kim HJ, Park JK. Destruction ofBacillus licheniformisspores by microwave irradiation. J Appl Microbiol 2009; 106:877-85. [DOI: 10.1111/j.1365-2672.2008.04056.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Carta R, Desogus F. The effect of low-power microwaves on the growth of bacterial populations in a plug flow reactor. AIChE J 2009. [DOI: 10.1002/aic.12034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Brinley T, Dock C, Truong VD, Coronel P, Kumar P, Simunovic J, Sandeep K, Cartwright G, Swartzel K, Jaykus LA. Feasibility of Utilizing Bioindicators for Testing Microbial Inactivation in Sweetpotato Purees Processed with a Continuous-Flow Microwave System. J Food Sci 2007; 72:E235-42. [DOI: 10.1111/j.1750-3841.2007.00371.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ortega YR, Liao J. Microwave inactivation of Cyclospora cayetanensis sporulation and viability of Cryptosporidium parvum oocysts. J Food Prot 2006; 69:1957-60. [PMID: 16924923 DOI: 10.4315/0362-028x-69.8.1957] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The efficacy of microwave heating on the viability of Cryptosporidium parvum oocysts and on the sporulation of Cyclospora cayetanensis oocysts for various periods of cooking times (0, 10, 15, 20, 30, and 45 s) at 100% power was determined. Cyclospora oocysts were stored in 2.5% dichromate at 23 degrees C for 2 weeks, and sporulation rates were then determined. The 4',6-diamidino-2-phenylindole and propidium iodide vital stain and the neonate animal infectivity assay determined Cryptosporidium oocyst viability. Cryptosporidium oocysts could be completely inactivated with as little as 20 s of cooking time, whereas Cyclospora sporulation was observed up to 45 s. Two of the examined microwave ovens were more effective at reducing sporulation and viability than the third one. Because of the variability of temperature achieved by the various ovens, cooking time was not an accurate parameter for parasite inactivation. Cryptosporidium oocysts could be inactivated only when temperatures of 80 degrees C or higher were reached in the microwave ovens.
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Affiliation(s)
- Ynes R Ortega
- Center for Food Safety and Department of Food Science and Technology, University of Georgia, Griffin, Georgia 30223, USA.
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