1
|
Trunet C, Vischer N, Coroller L, Brul S. Germination and outgrowth of Bacillus mycoides KBAB4 spores are impacted by environmental pH, quantitatively analyzed at single cell level with sporetracker. Food Microbiol 2024; 121:104509. [PMID: 38637073 DOI: 10.1016/j.fm.2024.104509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/06/2024] [Accepted: 02/24/2024] [Indexed: 04/20/2024]
Abstract
Quantifying spore germination and outgrowth heterogeneity is challenging. Single cell level analysis should provide supplementary knowledge regarding the impact of unfavorable conditions on germination and outgrowth dynamics. This work aimed to quantify the impact of pH on spore germination and outgrowth, investigating the behavior of individual spore crops, produced under optimal and suboptimal conditions. Bacillus mycoides (formerly B. weihenstephanensis) KBAB4 spores, produced at pH 7.4 and at pH 5.5 were incubated at different pH values, from pH 5.2 to 7.4. The spores were monitored by microscopy live imaging, in controlled conditions, at 30 °C. The images were analyzed using SporeTracker, to determine the state of single cells. The impact of pH on germination and outgrowth times and rates was estimated and the correlation between these parameters was quantified. The correlation between germination and outgrowth times was significantly higher at low pH. These results suggest that an environmental pressure highlights the heterogeneity of spore germination and outgrowth within a spore population. Results were consistent with previous observations at population level, now confirmed and extended to single cell level. Therefore, single cell level analyses can be used to quantify the heterogeneity of spore populations, which is of interest in order to control the development of spore-forming bacteria, responsible for food safety issues.
Collapse
Affiliation(s)
- C Trunet
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Écologie Microbienne, F-29000, Quimper, France.
| | - N Vischer
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands
| | - L Coroller
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Écologie Microbienne, F-29000, Quimper, France
| | - S Brul
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands
| |
Collapse
|
2
|
Wepukhulu M, Wachira P, Huria N, Sifuna P, Essuman S, Asamba M. Optimization of Growth Conditions for Chlorpyrifos-Degrading Bacteria in Farm Soils in Nakuru County, Kenya. BIOMED RESEARCH INTERNATIONAL 2024; 2024:1611871. [PMID: 38304346 PMCID: PMC10834098 DOI: 10.1155/2024/1611871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 02/03/2024]
Abstract
Chlorpyrifos (CP) is a chlorinated organophosphate pesticide. In Kenya, it is commonly used as an acaricide, particularly in dairy farming, leading to soil and water contamination. The study is aimed at isolating bacteria with CP-degrading potential and optimizing their growth conditions, including temperature, pH, and CP concentration. The enrichment culture technique was used, with minimal salt medium (MSM) supplemented with commercial grade CP. A multilevel factorial design was used to investigate the interactions of temperature, pH, and CP concentration. According to the findings, seven bacterial strains with potential to degrade CP were characterized and identified as Alcaligenes faecalis, Bacillus weihenstephanensis, Bacillus toyonensis, Alcaligenes sp. strain SCAU23, Pseudomonas sp. strain PB845W, Brevundimonas diminuta, and uncultured bacterium clone 99. Growth and biodegradation of bacteria differed significantly among the isolates across pH value, temperature, and concentrations (P ≤ 0.05). The optimum conditions for growth were pH 7, temperature of 25°C, and 25mg/l chlorpyrifos concentration, while optimum degradation conditions were pH 5, temp 25°C, and CP conc. 25mg/l. The Pearson correlation between optimum growth and degradation showed a weak positive relationship (R = 0.1144) for pH and strong positive relationship for temperature and concentration of chlorpyrifos. Other than pH, the study shows that there could be other cofactors facilitating the chlorpyrifos degradation process. The findings show that an efficient consortium, at 25°C and pH 5, can include Bacillus toyonensis 20SBZ2B and Alcaligenes sp. SCAU23 as they showed high optical density (OD) values under these conditions. These results indicate the potential for these bacteria to be employed in chlorpyrifos-contaminated ecosystem detoxification efforts upon manipulation of natural growth conditions. The findings of this study offer a potential foundation for future research into the reconstitution of a consortium. Based on the optimum conditions identified, the isolated bacterial strains could be further developed into a consortium to effectively degrade CP in both laboratory and field conditions. Dairy farmers can utilize the isolated strains and the consortia to decontaminate farm soils.
Collapse
Affiliation(s)
- Miriam Wepukhulu
- School of Biological Sciences, University of Nairobi, P.O. Box 30197-0100, Nairobi, Kenya
- Department of Dryland Agriculture and Natural Resources, Tharaka University, Marimanti, Kenya
| | - Peter Wachira
- School of Biological Sciences, University of Nairobi, P.O. Box 30197-0100, Nairobi, Kenya
| | - Nderitu Huria
- School of Biological Sciences, University of Nairobi, P.O. Box 30197-0100, Nairobi, Kenya
| | - Paul Sifuna
- Department of Medical Microbiology, Mount Kenya University, P.O. Box 342-01000, Thika, Kenya
| | - Suliman Essuman
- Department of Medical Microbiology, Mount Kenya University, P.O. Box 342-01000, Thika, Kenya
| | - Micah Asamba
- Department of Biochemistry, Microbiology, and Biotechnology, Kenyatta University, P.O. Box 43844, Nairobi, Kenya
| |
Collapse
|
3
|
Misiou O, Ellouze M, Koutsoumanis K. Cardinal models to describe the effect of temperature and pH on the growth of Anoxybacillus flavithermus & Bacillus licheniformis. Food Microbiol 2023; 112:104230. [PMID: 36906302 DOI: 10.1016/j.fm.2023.104230] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/20/2023] [Accepted: 01/22/2023] [Indexed: 01/26/2023]
Abstract
Anoxybacillus flavithermus and Bacillus licheniformis are among the predominant spore-formers of heat-processed foods. To our knowledge, no systematic analysis of growth kinetic data of A. flavithermus or B. licheniformis is currently available. In the present study, the growth kinetics of A. flavithermus and B. licheniformis in broth at various temperature and pH conditions were studied. Cardinal models were used to model the effect of the above-mentioned factors on the growth rates. The estimated values for the cardinal parameters Tmin,Topt,Tmax,pHmin and pH1/2 for A. flavithermus were 28.70 ± 0.26, 61.23 ± 0.16 and 71.52 ± 0.32 °C, 5.52 ± 0.01 and 5.73 ± 0.01, respectively, while for B. licheniformis they were 11.68 ± 0.03, 48.05 ± 0.15, 57.14 ± 0.01 °C, 4.71 ± 0.01 and 5.670 ± 0.08, respectively. The growth behaviour of these spoilers was also investigated in a pea beverage at 62 and 49 °C, respectively, to adjust the models to this product. The adjusted models were further validated at static and dynamic conditions and demonstrated good performance with 85.7 and 97.4% of predicted populations for A. flavithermus and B. licheniformis, respectively, being within the -10%-10% relative error (RE) zone. The developed models can be useful tools in assessing the potential of spoilage of heat-processed foods including plant-based milk alternatives.
Collapse
Affiliation(s)
- Ourania Misiou
- Department of Food Science and Technology, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Mariem Ellouze
- Food Safety Research Department, Nestlé Research, PO BOX44, CH-1000 Lausanne 26, Switzerland
| | - Konstantinos Koutsoumanis
- Department of Food Science and Technology, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
| |
Collapse
|
4
|
Le Marc Y, Postollec F, Huchet V, Ellouze M. Modelling the thermal inactivation of spores from different phylogenetic groups of Bacillus cereus. Int J Food Microbiol 2022; 368:109607. [DOI: 10.1016/j.ijfoodmicro.2022.109607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/29/2021] [Accepted: 02/27/2022] [Indexed: 11/29/2022]
|
5
|
Effect of abiotic factors and culture media on the growth of cheese-associated Nectriaceae species. Int J Food Microbiol 2021; 364:109509. [PMID: 35030441 DOI: 10.1016/j.ijfoodmicro.2021.109509] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/02/2021] [Accepted: 12/19/2021] [Indexed: 11/23/2022]
Abstract
Nectriaceae species have been described in various natural environments or as plant or human pathogens. Within this family, the Bisifusarium domesticum species is of particular interest for food mycologists as it is used for technological functions in various cheese productions. Moreover, it has only been isolated from the cheese environment so far and, until recently, was the only Nectriaceae species described in this food product. Recently, four novel cheese-associated Nectriaceae species have been described, including two associated to the Bisifusarium genus and two to a new genus, Longinectria gen. nov.. These observations raise questions concerning the potential adaptation of these species to the cheese environment. In this context, this study first focused on determining the impact of abiotic factors on the growth of isolates belonging to the five cheese-associated species (i.e. B. allantoides sp. nov., B. domesticum, B. penicilloides sp. nov., L. lagenoides gen. nov. sp. nov. and L. verticilliforme gen. nov. sp. nov.) but also included phylogenetically close species. To do so, fungal growth kinetics in liquid medium (Potato Dextrose Broth) were determined by laser nephelometry at different temperatures, pH and water activities using NaCl as a depressor. Growth modeling was then performed to estimate cardinal values for each abiotic factor. Secondly, fungal growth was also evaluated on Potato Dextrose Agar (synthetic medium), cheese agar (cheese-mimicking medium) and Raclette de Savoie cheese (actual cheese). Our results clearly highlighted physiological differences in growth characteristics between the studied cheese-associated Nectriaceae spp. and the "non-cheese" species which could suggest, for the former, an adaptation to this food matrix. Indeed, regarding the impact of the tested abiotic factors, statistical analyses confirmed this dichotomy, with for example the lowest optimal temperatures estimated for the cheese-associated species (Topt 19.1-23.1 °C) while the other Bisifusarium species exhibited the highest optimal temperatures (Topt 26.1-36.2 °C). As for the impact of growth media, radial growth measurements highlighted that B. domesticum was the least affected species for growth on Raclette de Savoie and even grew faster on cheese agar than on synthetic medium confirming its strong adaptation to the cheese environment.
Collapse
|
6
|
Luo W, Wang J, Wang Y, Tang J, Ren Y, Geng F. Bacteriostatic effects of high-intensity ultrasonic treatment on Bacillus subtilis vegetative cells. ULTRASONICS SONOCHEMISTRY 2021; 81:105862. [PMID: 34894527 PMCID: PMC8665408 DOI: 10.1016/j.ultsonch.2021.105862] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/25/2021] [Accepted: 12/06/2021] [Indexed: 05/05/2023]
Abstract
The bacteriostatic effects of high-intensity ultrasonic treatment (HIU) on Bacillus subtilis vegetative cells were evaluated, and the related mechanisms were explored using quantitative proteomics. The bacteriostatic effect of HIU on B. subtilis was proportional to the ultrasound treatment time and power, and the number of cultivable B. subtilis cells was decreased by approximately one log (at 270 W for 15 min) or half log (at 90 W for 25 min or 360 W for 5 min). Scanning electron microscopy images and gel electrophoresis results showed that HIU caused the destruction of the cell structure and intracellular protein leakage. In addition, HIU treatment at 270 W for 15 min resulted in the greatest decrease (84.22%) in intracellular adenosine triphosphate (ATP) content. The quantitative proteomic analysis showed that B. subtilis resisted the stress of HIU treatment by regulating the key proteins in physiological activities related to membrane transport (ATP-binding cassette [ABC] transporter), signal transduction (the two-component system), and energy metabolism (the tricarboxylic acid [TCA] cycle). HIU-induced physical damage, stress, and metabolic disorders were the main causes of the bacteriostatic effects on B. subtilis. These findings provide a foundation for the subsequent optimization and potential applications of HIU inactivation of B. subtilis.
Collapse
Affiliation(s)
- Wei Luo
- Institute for Egg Science and Technology, School of Food and Biological Engineering, Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, China
| | - Jinqiu Wang
- Institute for Egg Science and Technology, School of Food and Biological Engineering, Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, China
| | - Yi Wang
- Institute for Egg Science and Technology, School of Food and Biological Engineering, Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, China
| | - Jie Tang
- Institute for Egg Science and Technology, School of Food and Biological Engineering, Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, China
| | - Yuanhang Ren
- Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Sichuan Engineering & Technology Research Center of Coarse Cereal Industrialization, School of Food and Biological Engineering, Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, China
| | - Fang Geng
- Institute for Egg Science and Technology, School of Food and Biological Engineering, Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, China.
| |
Collapse
|
7
|
Makowski K, Leszczewicz M, Broncel N, Lipińska-Zubrycka L, Głębski A, Komorowski P, Walkowiak B. Isolation, Biochemical Characterisation and Identification of Thermotolerant and Cellulolytic Paenibacillus lactis and Bacillus licheniformis. Food Technol Biotechnol 2021; 59:325-336. [PMID: 34759764 PMCID: PMC8542176 DOI: 10.17113/ftb.59.03.21.7096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 06/24/2021] [Indexed: 11/12/2022] Open
Abstract
Research background Cellulose is an ingredient of waste materials that can be converted to other valuable substances. This is possible provided that the polymer molecule is degraded to smaller particles and used as a carbon source by microorganisms. Because of the frequently applied methods of pretreatment of lignocellulosic materials, the cellulases derived from thermophilic microorganisms are particularly desirable. Experimental approach We were looking for cellulolytic microorganisms able to grow at 50 °C and we described their morphological features and biochemical characteristics based on carboxymethyl cellulase (CMCase) activity and the API® ZYM system. The growth curves during incubation at 50 °C were examined using the BioLector® microbioreactor. Results and conclusions Forty bacterial strains were isolated from fermenting hay, geothermal karst spring, hot spring and geothermal pond at 50 °C. The vast majority of the bacteria were Gram-positive and rod-shaped with the maximum growth temperature of at least 50 °C. We also demonstrated a large diversity of biochemical characteristics among the microorganisms. The CMCase activity was confirmed in 27 strains. Hydrolysis capacities were significant in bacterial strains: BBLN1, BSO6, BSO10, BSO13 and BSO14, and reached 2.74, 1.62, 1.30, 1.38 and 8.02 respectively. Rapid and stable growth was observed, among others, for BBLN1, BSO10, BSO13 and BSO14. The strains fulfilled the selection conditions and were identified based on the 16S rDNA sequences. BBLN1, BSO10, BSO13 were classified as Bacillus licheniformis, whereas BSO14 as Paenibacillus lactis. Novelty and scientific contribution We described cellulolytic activity and biochemical characteristics of many bacteria isolated from hot environments. We are also the first to report the cellulolytic activity of thermotolerant P. lactis. Described strains can be a source of new thermostable cellulases, which are extremely desirable in various branches of circular bioeconomy.
Collapse
Affiliation(s)
- Krzysztof Makowski
- Industrial Biotechnology Laboratory, Bionanopark Ltd., Dubois 114/116, 93-465 Lodz, Poland.,Biotechnika, Tymienieckiego 25, 90-350 Lodz, Poland
| | - Martyna Leszczewicz
- Industrial Biotechnology Laboratory, Bionanopark Ltd., Dubois 114/116, 93-465 Lodz, Poland
| | - Natalia Broncel
- Industrial Biotechnology Laboratory, Bionanopark Ltd., Dubois 114/116, 93-465 Lodz, Poland
| | - Lidia Lipińska-Zubrycka
- Industrial Biotechnology Laboratory, Bionanopark Ltd., Dubois 114/116, 93-465 Lodz, Poland.,Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Adrian Głębski
- Industrial Biotechnology Laboratory, Bionanopark Ltd., Dubois 114/116, 93-465 Lodz, Poland
| | - Piotr Komorowski
- Molecular and Nanostructural Biophysics Laboratory, Bionanopark Ltd., Dubois 114/116, 93-465 Lodz, Poland.,Institute of Materials Science and Engineering, Lodz University of Technology, Stefanowskiego 1/15, 90-537 Lodz, Poland
| | - Bogdan Walkowiak
- Molecular and Nanostructural Biophysics Laboratory, Bionanopark Ltd., Dubois 114/116, 93-465 Lodz, Poland.,Institute of Materials Science and Engineering, Lodz University of Technology, Stefanowskiego 1/15, 90-537 Lodz, Poland
| |
Collapse
|
8
|
Løvdal T, Lunestad BT, Myrmel M, Rosnes JT, Skipnes D. Microbiological Food Safety of Seaweeds. Foods 2021; 10:foods10112719. [PMID: 34829000 PMCID: PMC8619114 DOI: 10.3390/foods10112719] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/25/2021] [Accepted: 10/30/2021] [Indexed: 12/13/2022] Open
Abstract
The use of seaweeds in the human diet has a long history in Asia and has now been increasing also in the western world. Concurrent with this trend, there is a corresponding increase in cultivation and harvesting for commercial production. Edible seaweed is a heterogenous product category including species within the green, red, and brown macroalgae. Moreover, the species are utilized on their own or in combinatorial food products, eaten fresh or processed by a variety of technologies. The present review summarizes available literature with respect to microbiological food safety and quality of seaweed food products, including processing and other factors controlling these parameters, and emerging trends to improve on the safety, utilization, quality, and storability of seaweeds. The over- or misuse of antimicrobials and the concurrent development of antimicrobial resistance (AMR) in bacteria is a current worldwide health concern. The role of seaweeds in the development of AMR and the spread of antimicrobial resistance genes is an underexplored field of research and is discussed in that context. Legislation and guidelines relevant to edible seaweed are also discussed.
Collapse
Affiliation(s)
- Trond Løvdal
- Nofima–Norwegian Institute of Food, Fisheries and Aquaculture Research, Department of Process Technology, Richard Johnsens Gate 4, P.O. Box 8034, NO-4021 Stavanger, Norway; (J.T.R.); (D.S.)
- Correspondence:
| | - Bjørn Tore Lunestad
- Institute of Marine Research, Section for Contaminants and Biohazards, Nordnesgaten 50, P.O. Box 1870, NO-5005 Bergen, Norway;
| | - Mette Myrmel
- Virology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Elizabeth Stephansens vei 15, P.O. Box 5003, NO-1433 Ås, Norway;
| | - Jan Thomas Rosnes
- Nofima–Norwegian Institute of Food, Fisheries and Aquaculture Research, Department of Process Technology, Richard Johnsens Gate 4, P.O. Box 8034, NO-4021 Stavanger, Norway; (J.T.R.); (D.S.)
| | - Dagbjørn Skipnes
- Nofima–Norwegian Institute of Food, Fisheries and Aquaculture Research, Department of Process Technology, Richard Johnsens Gate 4, P.O. Box 8034, NO-4021 Stavanger, Norway; (J.T.R.); (D.S.)
| |
Collapse
|
9
|
Stier P, Maul S, Kulozik U. Effect of sporulation conditions following solid-state cultivation on the resistance of Geobacillus stearothermophilus spores for use as bioindicators testing inactivation by H2O2. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.112078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
10
|
Kobayashi T, Azuma T, Yasokawa D, Yamaki S, Yamazaki K. Spore Heat Resistance and Growth Ability at Refrigeration Temperatures of Bacillus spp. and Paenibacillus spp. Biocontrol Sci 2021; 26:147-155. [PMID: 34556617 DOI: 10.4265/bio.26.147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
In this study, spore heat resistance and growth ability at refrigeration temperatures of Bacillus spp. and Paenibacillus spp. were determined. The spore D90°C of 67.6% (23 of 34 strains) of Bacillus and 73.9% (17 of 23 strains) of Paenibacillus was less than 15 min. The growth abilities of both genera were equivalent at 10°C. However, 71.1% (32 of 45 strains) of Paenibacillus and only 6.3% (3 of 48 strains) of Bacillus cereus group could grow at 4°C. Eight B. cereus strains formed spores with higher heat resistance compared to the other Bacillus strains assessed; however, they did not grow at tempreratures below 10°C. Conversely, four Paenibacillus strains formed spores with heat resistance equivalent to that of the eight B. cereus strains and grew at 6°C or lower. In particular, Paenibacillus sp. JCM13343 formed the highest heat-resistant spores (D90°C = 136.1 min) and grew well at 4°C. These results indicate that Paenibacillus can grow in processed foods during refrigerated storage and has the potential to cause spoilage as well as Bacillus. Therefore, Paenibacillus should be considered as one of the targets for microbiological control in refrigerated processed foods.
Collapse
Affiliation(s)
| | - Takanori Azuma
- Food Processing Research Center, Hokkaido Research Organization
| | | | - Shogo Yamaki
- Laboratory of Marine Food Science and Technology, Faculty of Fisheries Sciences, Hokkaido University
| | - Koji Yamazaki
- Laboratory of Marine Food Science and Technology, Faculty of Fisheries Sciences, Hokkaido University
| |
Collapse
|
11
|
Stier P, Kulozik U. Submerged Bioreactor Production of Geobacillus stearothermophilus ATCC 7953 Spores for Use as Bioindicators to Validate Hydrogen Peroxide Inactivation Processes. Methods Protoc 2021; 4:mps4030063. [PMID: 34564309 PMCID: PMC8482076 DOI: 10.3390/mps4030063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 11/30/2022] Open
Abstract
In the food and pharmaceutical industries, evaluating the sterilization performance preceding aseptic production processes is of central importance. In the case of hydrogen peroxide sterilization of solid surfaces, bioindicators (BI) consisting of spores of Bacillus atrophaeus or Geobacillus stearothermophilus are used to validate the effectiveness and efficiency of the inactivation procedure. Commercial production of G. stearothermophilus is commonly performed on agar plates, where cultivation and sporulation conditions are not well-defined. Therefore, the produced BI can vary in their resistance, which in turn creates unacceptable uncertainties in the evaluation of aseptic processes. Submerged production in the bioreactor would allow more control over sporulation conditions, while reducing production time, resistance variability, and avoidance of false-positive or false-negative test results. In addition, submerged production of G. stearothermophilus so far was a challenge to achieve sufficiently high spore concentrations for BI production. This study reports on the development of a method for submerged production of G. stearothermophilus spores (pH 7.0, 57 °C, 30% pO2) that can achieve 1.6 × 107 spores/mL with a resistance against 35% H2O2 at 25 °C of D25°C,35% H2O2 = 73 s. This resistance ranks within the range of commercially available BI, making the results directly transferable to industrial applications.
Collapse
|
12
|
Evelyn, Utami SP, Chairul. Effect of temperature and soluble solid on Bacillus subtilis and Bacillus licheniformis spore inactivation and quality degradation of pineapple juice. FOOD SCI TECHNOL INT 2021; 28:285-296. [PMID: 34018829 DOI: 10.1177/10820132211019143] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bacillus subtilis and Bacillus licheniformis spores can survive processing temperatures used in the thermal processes of high-acid foods. Therefore, this study investigated the thermal inactivation of B. subtilis and B. licheniformis spores in pineapple juice at different temperatures (85-100°C) and soluble solids (SS, 11-30°Brix). The quality of juices and microbial loads after the thermal treatments during storage at 4 °C for 35 days was then checked. A linear decrease in D-value was observed with increasing temperature of treatment. Furthermore, the D-values determined in pineapple juice were: D90°C=13.2 ± 0.5 mins, D95°C = 6.8 ± 0.9 mins and D100°C = 2.1 ± 1.7 mins for B. subtilis spores, and D85°C = 16.6 ± 0.4 mins, D90°C = 7.6 ± 0.5 mins and D95°C = 3.6 ± 1.5 min, for B. licheniformis. Generally, the susceptibility of the bacteria to soluble solid change was affected by the interaction between temperature, SS and strain. In addition, pasteurization processes of ≥95°C for ≥33.8 mins was needed to ensure a recommended 5-log reduction of B. subtilis spores and limit vitamin C degradation of pineapple juice within three-week of storage at 4 °C.
Collapse
Affiliation(s)
- Evelyn
- Department of Chemical Engineering, University of Riau, Pekanbaru, Indonesia
| | - Syelvia Putri Utami
- Department of Chemical Engineering, University of Riau, Pekanbaru, Indonesia
| | - Chairul
- Department of Chemical Engineering, University of Riau, Pekanbaru, Indonesia
| |
Collapse
|
13
|
Isolation, stability, and characteristics of high-pressure superdormant Bacillus subtilis spores. Int J Food Microbiol 2021; 343:109088. [PMID: 33621831 DOI: 10.1016/j.ijfoodmicro.2021.109088] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/15/2020] [Accepted: 01/30/2021] [Indexed: 12/26/2022]
Abstract
Bacterial spores are a major challenge in industrial decontamination processes owing to their extreme resistance. High-pressure (HP) of 150 MPa at 37 °C can trigger the germination of spores, making them lose their extreme resistance. Once their resistance is lost, germinated spores can easily be inactivated by a mild decontamination step. The implementation of this gentle germination-inactivation strategy is hindered by the presence of a subpopulation of so-called high-pressure superdormant (HPSD) spores, which resist germination or germinate only very slowly in response to HP. It is essential to understand the properties of HPSD spores and the underlying causes of superdormancy to tackle superdormant spores and further develop germination-inactivation strategies involving HP. This study investigated factors influencing the prevalence of HPSD spores and successfully isolated them by combining buoyant density centrifugation and fluorescence-activated cell sorting, which allowed further characterisation of HPSD spores for the first time. The prevalence of HPSD spores was shown to be strongly dependent on the HP dwell time, with increasing treatment times reducing their prevalence. Spore mutants lacking major germinant receptors further showed a highly increased prevalence of HPSD spores; 93% of the spores remained dormant even after a prolonged HP dwell time of 40 min. In contrast to nutrient germination, sublethal heat treatment of 75 °C for 30 min prior to pressure treatment did not induce spore activation and increase germination. The isolated HPSD spores did not show visible structural differences compared to the initial dormant spores when investigated with transmission electron microscopy. Re-sporulated HPSD spores showed similar germination capacity compared to the initial dormant spores, indicating that HPSD spores are most likely not genetically different from the rest of the population. Moreover, the majority of HPSD spores germinated when exposed a second time to the same germination treatment; however, the germination capacity was lower than that of the initial population. The fact that the majority of spores lost superdormancy when exposed a second time to the same trigger makes it unlikely that there is one factor that determines whether a spore germinates with a certain HP treatment or not. Instead, it seems possible that there are other reversible or cumulative causes. This study investigated the factors influencing spore HP superdormancy to improve the understanding of HPSD spores with regard to their stability, germination capacity, and potential underlying causes of spore HP superdormancy. This knowledge will contribute to the development of HP-based germination-inactivation strategies for gentle but effective spore control.
Collapse
|
14
|
Leguerinel I, Maucotel M, Arnoux T, Gaspari M, Desriac N, Chatzitzika C, Valdramidis V. Effects of heating and recovery media pH on the heat resistance of
Alicyclobacillus acidoterrestris
Ad 746 spores. J Appl Microbiol 2020; 129:1674-1683. [DOI: 10.1111/jam.14745] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 05/19/2020] [Accepted: 06/07/2020] [Indexed: 12/01/2022]
Affiliation(s)
- I. Leguerinel
- Laboratoire Universitaire de Biodiversité et Écologie Microbienne Univ Brest UMT ALTER’IX Quimper France
| | - M. Maucotel
- Department of Food Sciences and Nutrition Faculty of Health Sciences University of Malta Msida Malta
| | - T. Arnoux
- Department of Food Sciences and Nutrition Faculty of Health Sciences University of Malta Msida Malta
| | - M. Gaspari
- Department of Food Sciences and Nutrition Faculty of Health Sciences University of Malta Msida Malta
| | - N. Desriac
- Laboratoire Universitaire de Biodiversité et Écologie Microbienne Univ Brest UMT ALTER’IX Quimper France
| | - C. Chatzitzika
- Department of Food Sciences and Nutrition Faculty of Health Sciences University of Malta Msida Malta
| | - V.P. Valdramidis
- Department of Food Sciences and Nutrition Faculty of Health Sciences University of Malta Msida Malta
- Centre of Biobanking and Molecular Medicine University of Malta Msida Malta
| |
Collapse
|
15
|
Trunet C, Mtimet N, Mathot AG, Postollec F, Leguerinel I, Couvert O, Broussolle V, Carlin F, Coroller L. Suboptimal Bacillus licheniformis and Bacillus weihenstephanensis Spore Incubation Conditions Increase Heterogeneity of Spore Outgrowth Time. Appl Environ Microbiol 2020; 86:e02061-19. [PMID: 31900309 PMCID: PMC7054099 DOI: 10.1128/aem.02061-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/14/2019] [Indexed: 11/20/2022] Open
Abstract
Changes with time of a population of Bacillus weihenstephanensis KBAB4 and Bacillus licheniformis AD978 dormant spores into germinated spores and vegetative cells were followed by flow cytometry, at pH ranges of 4.7 to 7.4 and temperatures of 10°C to 37°C for B. weihenstephanensis and 18°C to 59°C for B. licheniformis Incubation conditions lower than optimal temperatures or pH led to lower proportions of dormant spores able to germinate and extended time of germination, a lower proportion of germinated spores able to outgrow, an extension of their times of outgrowth, and an increase of the heterogeneity of spore outgrowth time. A model based on the strain growth limits was proposed to quantify the impact of incubation temperature and pH on the passage through each physiological stage. The heat treatment temperature or time acted independently on spore recovery. Indeed, a treatment at 85°C for 12 min or at 95°C for 2 min did not have the same impact on spore germination and outgrowth kinetics of B. weihenstephanensis despite the fact that they both led to a 10-fold reduction of the population. Moreover, acidic sporulation pH increased the time of outgrowth 1.2-fold and lowered the proportion of spores able to germinate and outgrow 1.4-fold. Interestingly, we showed by proteomic analysis that some proteins involved in germination and outgrowth were detected at a lower abundance in spores produced at pH 5.5 than in those produced at pH 7.0, maybe at the origin of germination and outgrowth behavior of spores produced at suboptimal pH.IMPORTANCE Sporulation and incubation conditions have an impact on the numbers of spores able to recover after exposure to sublethal heat treatment. Using flow cytometry, we were able to follow at a single-cell level the changes in the physiological states of heat-stressed spores of Bacillus spp. and to discriminate between dormant spores, germinated spores, and outgrowing vegetative cells. We developed original mathematical models that describe (i) the changes with time of the proportion of cells in their different states during germination and outgrowth and (ii) the influence of temperature and pH on the kinetics of spore recovery using the growth limits of the tested strains as model parameters. We think that these models better predict spore recovery after a sublethal heat treatment, a common situation in food processing and a concern for food preservation and safety.
Collapse
Affiliation(s)
- C Trunet
- Univ Brest, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT ACTIA 19.03 ALTER'iX, Quimper, France
- ADRIA Food Expertise, UMT ACTIA 19.03 ALTER'iX, Quimper, France
| | - N Mtimet
- Univ Brest, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT ACTIA 19.03 ALTER'iX, Quimper, France
| | - A-G Mathot
- Univ Brest, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT ACTIA 19.03 ALTER'iX, Quimper, France
| | - F Postollec
- ADRIA Food Expertise, UMT ACTIA 19.03 ALTER'iX, Quimper, France
| | - I Leguerinel
- Univ Brest, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT ACTIA 19.03 ALTER'iX, Quimper, France
| | - O Couvert
- Univ Brest, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT ACTIA 19.03 ALTER'iX, Quimper, France
| | - V Broussolle
- INRAE, Avignon Université, UMR SQPOV, Avignon, France
| | - F Carlin
- INRAE, Avignon Université, UMR SQPOV, Avignon, France
| | - L Coroller
- Univ Brest, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, UMT ACTIA 19.03 ALTER'iX, Quimper, France
| |
Collapse
|
16
|
Trunet C, Ngo H, Coroller L. Quantifying permeabilization and activity recovery of Bacillus spores in adverse conditions for growth. Food Microbiol 2019; 81:115-120. [DOI: 10.1016/j.fm.2018.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 06/15/2018] [Accepted: 06/21/2018] [Indexed: 10/28/2022]
|
17
|
Microbiota of milk powders and the heat resistance and spoilage potential of aerobic spore-forming bacteria. Int Dairy J 2018. [DOI: 10.1016/j.idairyj.2018.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
18
|
Trunet C, Mtimet N, Mathot AG, Postollec F, Leguérinel I, Couvert O, Carlin F, Coroller L. Effect of incubation temperature and pH on the recovery of Bacillus weihenstephanensis spores after exposure to a peracetic acid-based disinfectant or to pulsed light. Int J Food Microbiol 2018; 278:81-87. [DOI: 10.1016/j.ijfoodmicro.2018.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 02/16/2018] [Accepted: 04/10/2018] [Indexed: 12/01/2022]
|
19
|
Dispersed phase volume fraction, weak acids and Tween 80 in a model emulsion: Effect on the germination and growth of Bacillus weihenstephanensis KBAB4 spores. Food Res Int 2018; 109:288-297. [PMID: 29803452 DOI: 10.1016/j.foodres.2018.04.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 04/12/2018] [Accepted: 04/12/2018] [Indexed: 11/21/2022]
Abstract
In foodstuffs, physico-chemical interactions and/or physical constraints between spores, inhibitors and food components may exist. Thus, the objective of this study was to investigate such interactions using a model emulsion as a microbial medium in order to improve bacterial spore control with better knowledge of the interactions in the formulation. Emulsions were prepared with hexadecane mixed with nutrient broth using sonication and were stabilized by Tween 80 and Span 80. The hexadecane ratio was either 35% (v/v) or 50% (v/v) and each emulsion was studied in the presence of organic acid (acetic, lactic or hexanoic) at two pH levels (5.5 and 6). Self-diffusion coefficients of emulsion components and the organic acids were measured by Pulsed Field Gradient-Nuclear Magnetic Resonance (PFG-NMR). The inhibition effect on the spore germination and cell growth of Bacillus weihenstephanensis KBAB4 was characterized by the measure of the probability of growth using the most probable number methodology, and the measure of the time taken for the cells to germinate and grow using a single cell Bioscreen® method and using flow cytometry. The inhibition of spore germination and growth in the model emulsion depended on the dispersed phase volume fraction and the pH value. The effect of the dispersed phase volume fraction was due to a combination of (i) the lipophilicity of the biocide, hexanoic acid, that may have had an impact on the distribution of organic acid between hexadecane and the aqueous phases and (ii) the antimicrobial activity of the emulsifier Tween 80 detected at the acidic pH value. The interface phenomena seemed to have a major influence. Future work will focus on the exploration of these phenomena at the interface.
Collapse
|
20
|
Bressuire-Isoard C, Broussolle V, Carlin F. Sporulation environment influences spore properties in Bacillus: evidence and insights on underlying molecular and physiological mechanisms. FEMS Microbiol Rev 2018; 42:614-626. [DOI: 10.1093/femsre/fuy021] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 05/16/2018] [Indexed: 02/07/2023] Open
Affiliation(s)
- Christelle Bressuire-Isoard
- UMR408 SQPOV “Sécurité et Qualité des Produits d'Origine Végétale”, INRA–Avignon Université, Centre de Recherche PACA, CS40509, Site Agroparc, 84914 Avignon Cedex 9, France
| | - Véronique Broussolle
- UMR408 SQPOV “Sécurité et Qualité des Produits d'Origine Végétale”, INRA–Avignon Université, Centre de Recherche PACA, CS40509, Site Agroparc, 84914 Avignon Cedex 9, France
| | - Frédéric Carlin
- UMR408 SQPOV “Sécurité et Qualité des Produits d'Origine Végétale”, INRA–Avignon Université, Centre de Recherche PACA, CS40509, Site Agroparc, 84914 Avignon Cedex 9, France
| |
Collapse
|
21
|
Tsuchido T. Research on Injured Microorganisms: Significance, To Date and Into the Future −Special Issues. J JPN SOC FOOD SCI 2018. [DOI: 10.3136/nskkk.65.67] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Tetsuaki Tsuchido
- Research Center of Microorganism Control, Research Institute for the 21st Century, Organization for Research Promotion, Osaka Prefecture University
| |
Collapse
|
22
|
Trunet C, Carlin F, Coroller L. Investigating germination and outgrowth of bacterial spores at several scales. Trends Food Sci Technol 2017. [DOI: 10.1016/j.tifs.2017.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
23
|
Sohier D, Riou A, Postollec F. A typical day working in a laboratory in 2050: are microbiologists becoming chemists and serene workers? Curr Opin Food Sci 2016. [DOI: 10.1016/j.cofs.2016.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
24
|
Effect of pH on Thermoanaerobacterium thermosaccharolyticum DSM 571 growth, spore heat resistance and recovery. Food Microbiol 2016; 55:64-72. [DOI: 10.1016/j.fm.2015.11.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/03/2015] [Accepted: 11/25/2015] [Indexed: 11/19/2022]
|
25
|
Mtimet N, Trunet C, Mathot AG, Venaille L, Leguérinel I, Coroller L, Couvert O. Modeling the behavior of Geobacillus stearothermophilus ATCC 12980 throughout its life cycle as vegetative cells or spores using growth boundaries. Food Microbiol 2015; 48:153-62. [DOI: 10.1016/j.fm.2014.10.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 10/15/2014] [Accepted: 10/31/2014] [Indexed: 10/24/2022]
|