1
|
Robles Hernandez MG, Gerlinsky M, Zhang JS, Gänzle MG. Use of Bacillus spp. as beneficial fermentation microbes in baking. Int J Food Microbiol 2024; 416:110646. [PMID: 38457886 DOI: 10.1016/j.ijfoodmicro.2024.110646] [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: 12/30/2023] [Revised: 02/24/2024] [Accepted: 02/26/2024] [Indexed: 03/10/2024]
Abstract
The development of minimally processed baked goods is dependent on new "clean label" functional ingredients that allow substitution of additives without compromising quality. We investigated the use of fermentation with Bacillus spp. as a novel approach to improve bread quality. Bacillus velezensis FUA2155 and Bacillus amyloliquefaciens Fad WE ferments were prepared using white wheat flour, wheat bran or buckwheat, and were added at a level of 2.5-20 % to bread dough. Ropy spoilage of bread was controlled by sourdough addition at a level of 10 or 20 %. The volume of white wheat bread and wheat bran bread increased by 47.4 and 62.5 % respectively with 2.5 % Bacillus ferments. Bread shelf-life was prolonged by the Bacillus ferment only at higher dosages that also reduced bread volume. The use of unfermented or sourdough fermented buckwheat improved bread volume and delayed mould spoilage. The characterization of water-soluble polysaccharides from sourdoughs and Bacillus ferments revealed that solubilization of arabinoxylans contributed to the increase in volume after fermentation of wheat but not after fermentation of buckwheat. In conclusion, Bacillus fermentation can be used to improve bread quality, adding to the diversity of microbes that are suitable for baking applications.
Collapse
Affiliation(s)
| | - Morgan Gerlinsky
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Justina S Zhang
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Michael G Gänzle
- University of Alberta, Dept. of Agricultural, Food and Nutritional Science, Edmonton, Canada.
| |
Collapse
|
2
|
Dymarska M, Widenmann A, Low KE, Abbott DW, Guan L, Gänzle MG. Conversion of Phytochemicals by Lactobacilli: (Phospho)-β-glucosidases Are Specific for Glucosylated Phytochemicals Rather than Disaccharides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:5428-5438. [PMID: 38415591 DOI: 10.1021/acs.jafc.3c08535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Food-fermenting lactobacilli convert glycosylated phytochemicals to glycosyl hydrolases and thereby alter their biological activity. This study aimed to investigate the microbial transformation of β-glucosides of phytochemicals in comparison with utilization of cellobiose. Four homofermentative and four heterofermentative lactobacilli were selected to represent the metabolic diversity of Lactobacillaceae. The genomes of Lactobacillus crispatus, Companilactobacillus paralimentarius, Lacticaseibacillus paracasei, and Lactiplantibacillus plantarum encoded for 8 to 22 enzymes, predominantly phospho-β-glucosidases, with predicted activity on β-glucosides. Levilactobacillus hammesii and Furfurilactobacillus milii encoded for 3 β-glucosidases, Furfurilactobacillus rossiae for one, and Fructilactobacillus sanfranciscensis for none. The hydrolysis of amygdalin, esculin, salicin, glucosides of quercetin and genistein, and ginsenosides demonstrated that several strains hydrolyzed β-glucosides of phytochemicals but not cellobiose. Taken together, several of the carbohydrate-active enzymes of food-fermenting lactobacilli are specific for glycosides of phytochemicals.
Collapse
Affiliation(s)
- Monika Dymarska
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
- Department of Food Chemistry and Biocatalysis, Wrocław University of Environmental and Life Sciences, 50-375 Wrocław, Poland
| | - Anna Widenmann
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Kristin E Low
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge T1J 4B1, Canada
| | - D Wade Abbott
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge T1J 4B1, Canada
| | - Leluo Guan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Michael G Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
- College of Bioengineering and Food Science, Hubei University of Technology, Wuhan, Hubei 430068, People's Republic of China
| |
Collapse
|
3
|
Gaur G, Chen C, Gänzle MG. Characterization of isogenic mutants with single or double deletions of four phenolic acid esterases in Lactiplantibacillus plantarum TMW1.460. Int J Food Microbiol 2023; 388:110100. [PMID: 36706579 DOI: 10.1016/j.ijfoodmicro.2023.110100] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 11/05/2022] [Accepted: 01/15/2023] [Indexed: 01/22/2023]
Abstract
In plants, hydroxycinnamic and hydroxybenzoic acids occur mainly as esters. This study aimed to determine the contribution of individual phenolic acid esterases in Lp. plantarum TMW1.460, which encodes for four esterases: TanA, Lp_0796, Est_1092 and a homolog of Lj0536 and Lj1228 that was termed HceP. To determine which of the phenolic acid esterases present in Lp plantarum TMW1.460 are responsible for esterase activity, mutants with deletions in lp_0796, est_1092, tanB, hceP, or hceP and est_1092 were constructed. The phenotype of wild type strain and mutants was determined with esters of hydroxycinnamic acids (chlorogenic acid and ethyl ferulate) and of hydroxybenzoic acids (methyl gallate, tannic acid and epigallocatechin-3-gallate). Lp. plantarum TMW1.460 hydrolysed chlorogenic acid, methyl ferulate and methyl gallate but not tannic acid or epigallocatechin gallate. The phenotype of mutant strains during growth in mMRS differed from the wild type as follows: Lp. plantarum TMW1.460ΔhceP did not hydrolyse esters of hydroxycinnamic acids; Lp. plantarum TMW1.460ΔtanB did not hydrolyse esters of hydroxybenzoic acids; disruption of est_1092 or Lp_0796 did not alter the phenotype. The phenotype of Lp. plantarum TMW1.460ΔΔhceP/est_1092 was identical to Lp. plantarum TMW1.460ΔhceP. The metabolism of phenolic acids during growth of the mutant strains in broccoli puree and wheat sourdough did not differ from metabolism of the wild type strain. In conclusion, esters of hydroxycinnamic and hydroxybenzoic acids each are hydrolysed by dedicated enzymes. The hydroxycinnamic acid esterase HceP is not expressed, or not active during growth of Lp. plantarum TMW1.460 in all food substrates.
Collapse
Affiliation(s)
- Gautam Gaur
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Alberta, Canada
| | - Chen Chen
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Alberta, Canada; Shanghai Institute of Technology, School of Perfume and Aroma Technology, Shanghai, PR China
| | - Michael G Gänzle
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Alberta, Canada.
| |
Collapse
|
4
|
Pham VD, Korver DR, Gänzle MG. Conversion of Phenolic Acids in Canola Fermentation: Impact on Antimicrobial Activity against Salmonella enterica and Campylobacter jejuni. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:2059-2069. [PMID: 36669157 DOI: 10.1021/acs.jafc.2c08322] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Canola meal (CM) is commonly used in poultry feeds. CM has a high protein content but also contains high levels of antimicrobial phenolic acids. Lactic acid bacteria can alter CM phenolic composition during fermentation and influence its antimicrobial activity against pathogens. Fermented CM was analyzed for phenolic composition using tandem mass spectrometry (LC-MS/MS) and high-performance liquid chromatography (HPLC). Sinapic acid and derivatives were the major phenolic acids in CM. Growth of lactobacilli in CM was attenuated when compared to cereal substrates. Glucosides and esters of sinapic acid were extensively hydrolyzed during fermentation with Lactiplantibacillus plantarum and Furfurilactobacillus milii. Lp. plantarum transformed hydroxycinnamic acids to dihydro, 4-vinyl, and 4-ethyl derivatives, Ff. milii reduced hydroxycinnamic acids to dihydroderivatives, but Limosilactobacillus reuteri did not convert hydroxycinnamic acids. The minimum inhibitory concentration of phenolic extracts was assessed with lactobacilli, Salmonella, and Campylobacter jejuni as indicator strains. Fermentation of CM with Lp. plantarum or Ff. milii increased the antimicrobial activity of phenolic extracts against Salmonella enterica and Campylobacter jejuni. Fermentation with Lm. reuteri TMW1.656 but not fermentation with Lm. reuteri TMW1.656ΔrtcN increased the antimicrobial activity of extracts owing to the production of reutericyclin. This study demonstrates that fermentation of CM with lactobacilli converts hydroxycinammic esters and may increase the antimicrobial activity of phenolic compounds in CM against pathogens.
Collapse
Affiliation(s)
- Vi D Pham
- Department. of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Douglas R Korver
- Department. of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Michael G Gänzle
- Department. of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| |
Collapse
|
5
|
Impact of High-Pressure Processing (HPP) on Selected Quality and Nutritional Parameters of Cauliflower (Brassica oleracea var. Botrytis). APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12126013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
In recent years, innovative food processing methods, such as high-pressure processing (HPP) treatment, have been shown to improve food quality. The purpose of this work was to determine the effects of high-pressure processing (HPP; 400 and 600 MPa for 2 or 5 min, 20 °C) of cauliflower. Microbial shelf-life (total aerobic count and spores), texture, color, drip loss, dry matter, antioxidative capacity, total phenolic content, and ascorbic acid were analyzed before and after processing, as well as during storage (4 °C) for up to 42 days. Among the different treatments, HPP at 600 MPa exhibited low microbial counts between days 14 and 28 of storage, while at 400 MPa already had high bacterial counts between days 7 and 14. HPP at both 400 and 600 MPa was the best method to maintain the color during storage. The texture of the cauliflower did not differ from the control during storage for HPP. For all samples, the dry matter content remained stable during storage, with few differences between treatments. The nutritional quality of high-pressure-processed cauliflower at 600 MPa for 2 min remained high until day 28. The overall results of this study demonstrate that HPP has the potential to preserve the quality of cauliflower.
Collapse
|
6
|
Pswarayi F, Qiao N, Gaur G, Gänzle M. Antimicrobial plant secondary metabolites, MDR transporters and antimicrobial resistance in cereal-associated lactobacilli: is there a connection? Food Microbiol 2021; 102:103917. [PMID: 34809942 DOI: 10.1016/j.fm.2021.103917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/19/2021] [Accepted: 09/24/2021] [Indexed: 11/27/2022]
Abstract
Cereal-associated lactobacilli resist antimicrobial plant secondary metabolites. This study aimed to identify multi-drug-resistance (MDR) transporters in isolates from mahewu, a Zimbabwean fermented cereal beverage, and to determine whether these MDR-transporters relate to resistance against phenolic compounds and antibiotics. Comparative genomic analyses indicated that all seven mahewu isolates harbored multiple MATE and MFS MDR proteins. Strains of Lactiplantibacillus plantarum and Limosilactobacillus fermentum encoded for the same gene, termed mahewu phenolics resistance gene mprA, with more than 99% nucleotide identity, suggesting horizontal gene transfer. Strains of Lp. plantarum were more resistant than strains of Lm. fermentum to phenolic acids, other antimicrobials and antibiotics but the origins of strains were not related to resistance. The resistance of several strains exceeded EFSA thresholds for several antibiotics. Analysis of gene expression in one strain each of Lp. plantarum and Lm. fermentum revealed that at least one MDR gene in each strain was over-expressed during growth in wheat, sorghum and millet relative to growth in MRS5 broth. In addition, both strains over-expressed a phenolic acid reductase. The results suggest that diverse lactobacilli in mahewu share MDR transporters acquired by lateral gene transfer, and that these transporters mediate resistance to secondary plant metabolites and antibiotics.
Collapse
Affiliation(s)
- Felicitas Pswarayi
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Nanzhen Qiao
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Gautam Gaur
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Michael Gänzle
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada.
| |
Collapse
|
7
|
Lu W, Fu N, Woo MW, Chen XD. Exploring the interactions between Lactobacillus rhamnosus GG and whey protein isolate for preservation of the viability of bacteria through spray drying. Food Funct 2021; 12:2995-3008. [PMID: 33704292 DOI: 10.1039/d0fo02906h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Protective agents used in spray drying protect the activity of lactic acid bacteria (LAB) by stabilizing the subcellular structures, constituting a protective layer at the cellular surface, or having mild drying kinetics. The effects of a reputed protectant, whey protein isolate (WPI), on Lactobacillus rhamnosus GG (LGG) were examined by exposing the cells to WPI solution to induce protein adsorption at the cellular surface prior to spray drying. WPI-treated LGG demonstrated enhanced thermotolerance with cell survival increased by 1.64 log after heat treatment. The survival after spray drying was significantly decreased from 45.75% to 8.6% and from 32.96% to 10.44%, when the WPI-treated cells were resuspended in trehalose solution or reconstituted skimmed milk as protectant, respectively, associated with decreased growth capability and metabolic activity. The contact with WPI appeared to stimulate the cellular response of LGG. With well-maintained cell viability and intact cellular membrane, the metabolic activity of WPI-treated LGG was decreased, and subsequent resuspension of the cells in trehalose solution led to a reduction in the stability of the cellular surface charge. The WPI-treated cells showed marginally increased surface roughness, indicating possible WPI attachment, but there was no thick protein coverage at the cellular surface and the size distribution of cells was unaffected. It was proposed that the enhanced thermotolerance and the decreased survival of spray-dried LGG could be linked to the cellular response toward WPI and protectant media, which may vary among individual LAB strains. Modulating the strain-specific interactions between the LAB cells and the protectant constituents could be crucial to maximizing cell viability retention after spray drying.
Collapse
Affiliation(s)
- Wenjie Lu
- FoodPRINT International Associated Laboratory INRAE, School of Chemical and Environmental Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123, China.
| | | | | | | |
Collapse
|
8
|
Sehrawat R, Kaur BP, Nema PK, Tewari S, Kumar L. Microbial inactivation by high pressure processing: principle, mechanism and factors responsible. Food Sci Biotechnol 2021; 30:19-35. [PMID: 33552614 DOI: 10.1007/s10068-020-00831-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/20/2020] [Accepted: 09/23/2020] [Indexed: 12/12/2022] Open
Abstract
High-pressure processing (HPP) is a novel technology for the production of minimally processed food products with better retention of the natural aroma, fresh-like taste, additive-free, stable, convenient to use. In this regard safety of products by microbial inactivation is likely to become an important focus for food technologists from the research and industrial field. High pressure induces conformational changes in the cell membranes, cell morphology. It perturbs biochemical reactions, as well as the genetic mechanism of the microorganisms, thus ensures the reduction in the microbial count. Keeping in view the commercial demand of HPP products, the scientific literature available on the mechanism of inactivation by high pressure and intrinsic and extrinsic factors affecting the efficiency of HPP are systematically and critically analyzed in this review to develop a clear understanding of these issues. Modeling applied to study the microbial inactivation kinetics by HPP is also discussed for the benefit of interested readers.
Collapse
Affiliation(s)
- Rachna Sehrawat
- Department of Food Engineering, National Institute of Food Technology Entrepreneurship and Management, Kundli, Sonepat, Haryana 131028 India.,Department of Food Process Engineering, National Institute of Technology Rourkela, Rourkela, Odisha 769008 India
| | - Barjinder Pal Kaur
- Department of Food Engineering, National Institute of Food Technology Entrepreneurship and Management, Kundli, Sonepat, Haryana 131028 India
| | - Prabhat K Nema
- Department of Food Engineering, National Institute of Food Technology Entrepreneurship and Management, Kundli, Sonepat, Haryana 131028 India
| | - Somya Tewari
- Department of Food Engineering, National Institute of Food Technology Entrepreneurship and Management, Kundli, Sonepat, Haryana 131028 India
| | - Lokesh Kumar
- Department of Wine, Food and Molecular Biosciences, Lincoln University, Lincoln, Canterbury 7647 New Zealand
| |
Collapse
|
9
|
Hao F, Fu N, Ndiaye H, Woo MW, Jeantet R, Chen XD. Thermotolerance, Survival, and Stability of Lactic Acid Bacteria After Spray Drying as Affected by the Increase of Growth Temperature. FOOD BIOPROCESS TECH 2021. [DOI: 10.1007/s11947-020-02571-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
10
|
Fundamental Study of Decellularization Method Using Cyclic Application of High Hydrostatic Pressure. MICROMACHINES 2020; 11:mi11111008. [PMID: 33203164 PMCID: PMC7696941 DOI: 10.3390/mi11111008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/29/2022]
Abstract
Decellularized tissues are promising materials that mainly consist of extracellular matrices (ECMs) obtained by removing all cells from organs and tissues. High hydrostatic pressure (HHP) has been used for decellularization to remove cells physically from organs or tissues rather than by chemical methods. However, ultrahigh pressure induces denaturation of the ECM structure. In this study, we examined the effects of cyclic HHP at low and high pressures on the cell membrane structure to establish a novel decellularization method that enables decellularization without the denaturation of the ECM. A decellularization device using cyclic HHP (maximum pressure: 250 MPa, cycle number: 5) was developed. NB1RGB cell suspension was injected into a plastic bag to be subjected to cyclic HHP. After applying cyclic HHP, the amount of DNA inside the cells and the morphological changes of the cells were evaluated. As a result, the amount of DNA inside the cells decreased after the cyclic HHP compared to the static HHP. In addition, cyclic HHP was suggested to promote the destruction of the cell and nuclear membrane. In conclusion, it was revealed that the cell structure could be denatured and destroyed by cyclic HHP at a lower level than that of previous approaches.
Collapse
|
11
|
Peng K, Koubaa M, Bals O, Vorobiev E. Recent insights in the impact of emerging technologies on lactic acid bacteria: A review. Food Res Int 2020; 137:109544. [DOI: 10.1016/j.foodres.2020.109544] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 12/14/2022]
|
12
|
Impact of ultra high pressure on microbial characteristics of rose pomace beverage: A comparative study against conventional heat pasteurization. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
13
|
Genetic Determinants of Hydroxycinnamic Acid Metabolism in Heterofermentative Lactobacilli. Appl Environ Microbiol 2020; 86:AEM.02461-19. [PMID: 31862715 DOI: 10.1128/aem.02461-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/16/2019] [Indexed: 02/06/2023] Open
Abstract
Phenolic acids are among the most abundant phenolic compounds in edible parts of plants. Lactic acid bacteria (LAB) metabolize phenolic acids, but the enzyme responsible for reducing hydroxycinnamic acids to phenylpropionic acids (HcrB) was only recently characterized in Lactobacillus plantarum In this study, heterofermentative LAB species were screened for their hydroxycinnamic acid metabolism. Data on strain-specific metabolism in combination with comparative genomic analyses identified homologs of HcrB as putative phenolic acid reductases. Par1 and HcrF both encode putative multidomain proteins with 25% and 63% amino acid identity to HcrB, respectively. Of these genes, par1 in L. rossiae and hcrF in L. fermentum were overexpressed in response to hydroxycinnamic acids. The deletion of par1 in L. rossiae led to the loss of phenolic acid metabolism. The strain-specific metabolism of phenolic acids was congruent with the genotype of lactobacilli; however, phenolic acid reductases were not identified in strains of Weissella cibaria that reduced hydroxycinnamic acids to phenylpropionic acids. Phylogenetic analysis of major genes involved in hydroxycinnamic acid metabolism in strains of the genus Lactobacillus revealed that Par1 was found to be the most widely distributed phenolic acid reductase, while HcrB was the least abundant, present in less than 9% of Lactobacillus spp. In conclusion, this study increased the knowledge on the genetic determinants of hydroxycinnamic acid metabolism, explaining the species- and strain-specific metabolic variations in lactobacilli and providing evidence of additional enzymes involved in hydroxycinnamic acid metabolism of lactobacilli.IMPORTANCE The metabolism of secondary plant metabolites, including phenolic compounds, by food-fermenting lactobacilli is a significant contributor to the safety, quality, and nutritional quality of fermented foods. The enzymes mediating hydrolysis, reduction, and decarboxylation of phenolic acid esters and phenolic acids in lactobacilli, however, are not fully characterized. The genomic analyses presented here provide evidence for three novel putative phenolic acid reductases. Matching comparative genomic analyses with phenotypic analysis and quantification of gene expression indicates that two of the three putative phenolic acid reductases, Par1 and HcrF, are involved in reduction of hydroxycinnamic acids to phenylpropionic acids; however, the activity of Par2 may be unrelated to phenolic acids and recognizes other secondary plant metabolites. These findings expand our knowledge on the metabolic potential of lactobacilli and facilitate future studies on activity and substrate specificity of enzymes involved in metabolism of phenolic compounds.
Collapse
|
14
|
Laidlaw AM, Gänzle MG, Yang X. Comparative assessment of qPCR enumeration methods that discriminate between live and dead Escherichia coli O157:H7 on beef. Food Microbiol 2019; 79:41-47. [DOI: 10.1016/j.fm.2018.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 11/05/2018] [Accepted: 11/13/2018] [Indexed: 11/28/2022]
|
15
|
Viability of Molds and Bacteria in Tempeh Processed with Supercritical Carbon Dioxides during Storage. INTERNATIONAL JOURNAL OF FOOD SCIENCE 2018; 2018:8591015. [PMID: 30402459 PMCID: PMC6191950 DOI: 10.1155/2018/8591015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 08/13/2018] [Accepted: 08/28/2018] [Indexed: 11/17/2022]
Abstract
Application of supercritical carbon dioxide for processing of food products has an impact on microbial inactivation and food quality. This technique is used to preserve tempeh due to no heat involved. The quality of tempeh is highly influenced by mold growth because of its role in forming a compact texture, white color, and functional properties as well as consumer acceptance. This study aims to observe viability of molds and bacteria in tempeh after processed with supercritical CO2 and to determine the best processing conditions which can maintain mold growth and reduce the number of bacteria in tempeh. For that purpose, tempeh was treated using high pressure CO2 at 7.6 MPa (supercritical CO2) and at 6.3 MPa (sub/near supercritical CO2) with incubation period of 5, 10, 15, and 20 min. The best treatment obtained was used to process tempeh for storage study. The results showed that there was a significant interaction between pressure and incubation period for bacterial and mold viability at ρ>0.05. Reduction of bacteria and molds increased with longer incubation period. Molds were undetectable after treatment for 20 min with either supercritical CO2 or sub-supercritical, and bacteria significantly reduced up to 2.40 log CFU/g. On the other hand, sub-supercritical CO2 for 10 min was the best processing method because molds survived 4.3x104 CFU/gram after treatment and were able to grow during storage at 30°C, producing white mycelium as indicated by increasing the L⁎ color value and tempeh acceptability. The inactivation of mold was reversible causing it to grow back during storage under suitable conditions. Tempeh matrix composition can provide protection against the destructive effects of supercritical CO2. Gram-positive bacteria were more resistant than Gram-negative. In conclusion, sub-supercritical CO2 can act as a method of cold pasteurization of tempeh and can be used as an alternative method to preserve tempeh.
Collapse
|
16
|
Sreedevi P, Rao PS. Microbial destruction kinetics of high-pressure-processed sugarcane juice (Saccharum officinarum). J FOOD PROCESS ENG 2018. [DOI: 10.1111/jfpe.12850] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- P. Sreedevi
- Department of Agricultural and Food Engineering; Indian Institute of Technology; Kharagpur, West Bengal India
| | - P. Srinivasa Rao
- Department of Agricultural and Food Engineering; Indian Institute of Technology; Kharagpur, West Bengal India
| |
Collapse
|
17
|
Teixeira JS, Repková L, Gänzle MG, McMullen LM. Effect of Pressure, Reconstituted RTE Meat Microbiota, and Antimicrobials on Survival and Post-pressure Growth of Listeria monocytogenes on Ham. Front Microbiol 2018; 9:1979. [PMID: 30210467 PMCID: PMC6119701 DOI: 10.3389/fmicb.2018.01979] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 08/06/2018] [Indexed: 01/19/2023] Open
Abstract
Pressure treatment of ready-to-eat (RTE) meats extends the shelf life and reduces risks associated with Listeria monocytogenes. However, pressure reduces numbers of Listeria on ham by less than 5 log (CFU/g) and pressure effects on other meat microbiota are poorly documented. This study investigated the impact of pressure and RTE meat microbiota, with or without nisin and rosemary oil, on survival of Listeria after refrigerated storage. Ham was inoculated with a 5-strain cocktail of L. monocytogenes alone or with a cocktail of RTE meat microbiota consisting of Brochothrix thermosphacta, Carnobacterium maltaromaticum, Leuconostoc gelidum, and Lactobacillussakei. Products were treated at 500 MPa at 5°C for 1 or 3 min, with or without rosemary extract or nisin. Surviving cells were differentially enumerated after pressure treatment and after 4 weeks of refrigerated storage. After 4 weeks of storage, products were also analyzed by high throughput sequencing of 16S rRNA amplicons. Pressure treatment reduced counts of Listeria by 1 to 2 log (CFU/g); inactivation of RTE meat microbiota was comparable. Counts of Listeria increased by 1–3 log (CFU/g) during refrigerated storage. RTE meat microbiota did not influence pressure inactivation of Listeria but prevented growth of Listeria during refrigerated storage. Rosemary extract did not influence bacterial inactivation or growth. The combination of nisin with pressure treatment for 3 min reduced counts of Listeria and meat microbiota by >5 log (CFU/g); after 4 weeks of storage, counts were below the detection limit. In conclusion, pressure alone does not eliminate Listeria or other microbiota on RTE ham; however, the presence of non-pathogenic microbiota prevents growth of Listeria on pressure treated ham and has a decisive influence on post-pressure survival and growth.
Collapse
Affiliation(s)
- Januana S Teixeira
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Lenka Repková
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Michael G Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Lynn M McMullen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
18
|
Reitermayer D, Kafka TA, Lenz CA, Vogel RF. Interrelation between Tween and the membrane properties and high pressure tolerance of Lactobacillus plantarum. BMC Microbiol 2018; 18:72. [PMID: 30001697 PMCID: PMC6044075 DOI: 10.1186/s12866-018-1203-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 06/14/2018] [Indexed: 11/16/2022] Open
Abstract
Tween® 80 is a frequently used supplement of media for the cultivation of lactic acid bacteria. We investigated its effect on the cell physiology and stress tolerance of Lactobacillus (L.) plantarum. Data on the transcriptomic response to Tween 80 supplementation and its effects on cellular fatty acid profiles and growth characteristics are compared with data characterizing the effect of Tween 80, other Tween types and free fatty acids on the high hydrostatic pressure (HHP) tolerance of L. plantarum strain TMW 1.708. These include effects on cell viability, sub-lethal injury, metabolic activity, protein release and propidium iodide uptake. Tween 80 caused the downregulation of fatty acid biosynthesis and an increase in oleic acid and cyclopropane fatty acid levels in the cell membrane. Tween 20, Tween 80 and free oleic acid, but not Tween 40, Tween 60 and other free fatty acids, conferred resistance against HHP. Tween 80 diminished pressure-induced loss of metabolic activity, protein release and uptake of propidium iodide. However, loss of cell viability exceeded by far membrane permeabilization, suggesting that membrane permeabilization, which has frequently been postulated as a major factor in HHP inactivation of microbes, is not necessarily required for HHP-induced cell death of Lactobacillus plantarum.
Collapse
Affiliation(s)
| | | | | | - Rudi F Vogel
- Technische Universität München, Freising, Germany.
| |
Collapse
|
19
|
Ramaroson M, Guillou S, Rossero A, Rezé S, Anthoine V, Moriceau N, Martin JL, Duranton F, Zagorec M. Selection procedure of bioprotective cultures for their combined use with High Pressure Processing to control spore-forming bacteria in cooked ham. Int J Food Microbiol 2018; 276:28-38. [PMID: 29655009 DOI: 10.1016/j.ijfoodmicro.2018.04.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/09/2018] [Accepted: 04/04/2018] [Indexed: 10/17/2022]
Abstract
High Pressure Processing (HPP) and biopreservation can contribute to food safety by inactivation of bacterial contaminants. However these treatments are inefficient against bacterial endospores. Moreover, HPP can induce spore germination. The objective of this study was to select lactic acid bacteria strains to be used as bioprotective cultures, to control vegetative cells of spore-forming bacteria in ham after application of HPP. A collection of 63 strains of various origins was screened for their antagonistic activity against spore-forming Bacillus and Clostridium species and their ability to resist to HPP. Some safety requirements should also be considered prior to their introduction into the food chain. Hence, the selection steps included the assessment of biogenic amine production and antibiotic resistance. No strain produced histamine above the threshold detection level of 50 ppm. From the assessment of antibiotic resistance against nine antibiotics, 14 susceptible strains were kept. Antagonistic action of the 14 strains was then assessed by the well diffusion method against pathogenic or spoilage spore-forming species as Bacillus cereus, Clostridium sp. like botulinum, Clostridium frigidicarnis, and Clostridium algidicarnis. One Lactobacillus curvatus strain and one Lactococcus lactis strain were ultimately selected for their widest inhibitory spectrum and their potential production of bacteriocin. A Lactobacillus plantarum strain was included as control. Their resistance to HPP and ability to regrow during chilled storage was then assessed in model ham liquid medium. Treatments of pressure intensities of 400, 500, and 600 MPa, and durations of 1, 3, 6, and 10 min were applied. After treatment, cultures were incubated at 8 °C during 30 days. Inactivation curves were then fitted by using a reparameterized Weibull model whereas growth curves were modelled with a logistic model. Although the two Lactobacillus strains were more resistant than L. lactis to HPP, the latter was the only strain able to regrow following HPP. The absence of biogenic amine production of this strain after growth on diced cube cooked ham was also shown. In conclusion this L. lactis strain could be selected as representing the best candidate for a promising preservative treatment combining biopreservation and HPP to control spore-forming bacteria in cooked ham.
Collapse
Affiliation(s)
- Mihanta Ramaroson
- SECALIM, INRA, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | - Sandrine Guillou
- SECALIM, INRA, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | - Albert Rossero
- SECALIM, INRA, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | - Sandrine Rezé
- SECALIM, INRA, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | - Valérie Anthoine
- SECALIM, INRA, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | - Nicolas Moriceau
- SECALIM, INRA, Oniris, Université Bretagne Loire, 44307, Nantes, France
| | - Jean-Luc Martin
- IFIP, French Institute for the Pig and Pork Industry, 94 700 Maisons-Alfort, France
| | - Frédérique Duranton
- CTCPA, French Food Industry Science and Technology Center, 44300 Nantes, France
| | - Monique Zagorec
- SECALIM, INRA, Oniris, Université Bretagne Loire, 44307, Nantes, France.
| |
Collapse
|
20
|
Effect of High-Pressure Processing on Quality and Microbiological Properties of a Fermented Beverage Manufactured from Sweet Whey Throughout Refrigerated Storage. FOOD BIOPROCESS TECH 2018. [DOI: 10.1007/s11947-018-2078-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
21
|
Xu L, Garner AL, Tao B, Keener KM. Microbial Inactivation and Quality Changes in Orange Juice Treated by High Voltage Atmospheric Cold Plasma. FOOD BIOPROCESS TECH 2017. [DOI: 10.1007/s11947-017-1947-7] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
22
|
Santos LM, Oliveira FA, Ferreira EH, Rosenthal A. Application and possible benefits of high hydrostatic pressure or high-pressure homogenization on beer processing: A review. FOOD SCI TECHNOL INT 2017; 23:561-581. [PMID: 28605941 DOI: 10.1177/1082013217714670] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Beer is the most consumed beverage in the world, especially in countries such as USA, China and Brazil.It is an alcoholic beverage made from malted cereals, and the barley malt is the main ingredient, added with water, hops and yeast. High-pressure processing is a non-traditional method to preserve food and beverages. This technology has become more interesting compared to heat pasteurization, due to the minimal changes it brings to the original nutritional and sensory characteristics of the product, and it comprises two processes: high hydrostatic pressure, which is the most industrially used process, and high-pressure homogenization. The use of high pressure almost does not affect the molecules that are responsible for the aroma and taste, pigments and vitamins compared to the conventional thermal processes. Thus, the products processed by high-pressure processing have similar characteristics compared to fresh products, including beer. The aim of this paper was to review what has been investigated about beer processing using this technology regarding the effects on physicochemical, microbiology and sensory characteristics and related issues. It is organized by processing steps, since high pressure can be applied to malting, mashing, boiling, filtration and pasteurization. Therefore, the beer processed with high-pressure processing may have an extended shelf-life because this process can inactivate beer spoilage microorganisms and result in a superior sensory quality related to freshness and preservation of flavors as it does to juices that are already commercialized. However, beyond this application, high-pressure processing can modify protein structures, such as enzymes that are present in the malt, like α- and β-amylases. This process can activate enzymes to promote, for example, saccharification, or instead inactivate at the end of mashing, depending on the pressure the product is submitted, besides being capable of isomerizing hops to raise beer bitterness. As a consequence, the process may reduce steam demand and residue generation. Therefore, the use of high-pressure processing can potentially replace or be combined with heat processes usually applied to beer, thus bringing benefits to the sensory quality of the product and to the environment.
Collapse
Affiliation(s)
- Lígia Mr Santos
- 1 SENAI-RJ, Vassouras and Food Technology Department Federal Rural University of Rio de Janeiro, UFRRJ, Seropédica, Rio de Janeiro, Brazil
| | - Fabiano A Oliveira
- 2 Federal Center for Technological Education, Cefet / RJ, Valença, Rio de Janeiro, Brazil
| | - Elisa Hr Ferreira
- 3 Food Technology Department Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil
| | | |
Collapse
|
23
|
A novel soybean flour as a cryoprotectant in freeze-dried Bacillus subtilis SB-MYP-1. Lebensm Wiss Technol 2017. [DOI: 10.1016/j.lwt.2016.11.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
24
|
Meng J, Gong Y, Qian P, Yu JY, Zhang XJ, Lu RR. Combined effects of ultra-high hydrostatic pressure and mild heat on the inactivation of Bacillus subtilis. Lebensm Wiss Technol 2016. [DOI: 10.1016/j.lwt.2015.12.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
25
|
Morimoto N, Jinno C, Mahara A, Kakudo N, Fujisato T, Kusumoto K, Suzuki S, Yamaoka T. Verification of the Inactivation of Melanocytic Nevus in vitro Using a Newly Developed Portable High Hydrostatic Pressure Device. Cells Tissues Organs 2016; 201:170-9. [PMID: 27002537 DOI: 10.1159/000444048] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2016] [Indexed: 11/19/2022] Open
Abstract
High hydrostatic pressure (HHP) technology is a physical method for inactivating tissue. We reported that nevus specimens were inactivated after HHP at 200 MPa and that the inactivated nevus could be used as autologous dermis for covering skin defects. In this study, we verified the inactivation of nevus specimens using a newly developed portable HHP device which will be used in a clinical trial. Nevus tissue specimens were obtained from 5 patients (mean age 7.2 years, range 1-19). We cultured fibroblasts and nevus cells from the tissue specimens and then evaluated their inactivation after HHP at 200 MPa by confirming the attachment of the suspensions and by the live/dead staining of the suspensions, through the dissociation of the cells on chamber slides and by the live/dead staining of the remaining cells. The cells were also quantitatively evaluated by WST-8 assay. We then confirmed the inactivation of the nevus specimens after HHP using explant culture. Our results indicated that fibroblasts and nevus cells were inactivated after HHP at 200 MPa, with the exception of a small percentage of green-colored cells, which reflected the remaining activity of the cellular esterases after HHP. No cells migrated from the nevus specimens after HHP at 200 MPa. We verified the inactivation of fibroblasts and nevus cells cultured from nevus specimens, and in the nevus samples themselves after pressurization at 200 MPa using this device. This device could be used in clinical trials for giant congenital melanocytic nevi and may thus become useful in various medical fields.
Collapse
Affiliation(s)
- Naoki Morimoto
- Department of Plastic and Reconstructive Surgery, Kansai Medical University, Hirakata, Osaka, Japan
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Jofré A, Aymerich T, Garriga M. Impact of different cryoprotectants on the survival of freeze-dried Lactobacillus rhamnosus and Lactobacillus casei/paracasei during long-term storage. Benef Microbes 2016; 6:381-6. [PMID: 25380798 DOI: 10.3920/bm2014.0038] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The production of long shelf-life highly concentrated dried probiotic/starter cultures is of paramount importance for the food industry. The aim of the present study was to evaluate the protective effect of glucose, lactose, trehalose, and skim milk applied alone or combined upon the survival of potentially probiotic Lactobacillus rhamnosus CTC1679, Lactobacillus casei/paracasei CTC1677 and L. casei/paracasei CTC1678 during freeze-drying and after 39 weeks of storage at 4 and 22 °C. Immediately after freeze-drying, the percentage of survivors was very high (≥ 94%) and only slight differences were observed among strains and cryoprotectants. In contrast, during storage, survival in the dried state depended on the cryoprotectant, temperature and strain. For all the protectants assayed, the stability of the cultures was remarkably higher when stored under refrigeration (4 °C). Under these conditions, skim milk alone or supplemented with trehalose or lactose showed the best performance (reductions ≤ 0.9 log units after 39 weeks of storage). The lowest survival was observed during non-refrigerated storage and with glucose and glucose plus milk; no viable cells left at the end of the storage period. Thus, freeze-drying in the presence of appropriate cryoprotectants allows the production of long shelf-life highly concentrated dried cultures ready for incorporation in high numbers into food products as starter/potential probiotic cultures.
Collapse
Affiliation(s)
- A Jofré
- IRTA-Food Safety Programme, Finca Camps i Armet, 17121 Monells, Spain
| | - T Aymerich
- IRTA-Food Safety Programme, Finca Camps i Armet, 17121 Monells, Spain
| | - M Garriga
- IRTA-Food Safety Programme, Finca Camps i Armet, 17121 Monells, Spain
| |
Collapse
|
27
|
Microbiological Aspects of High-Pressure Processing of Food: Inactivation of Microbial Vegetative Cells and Spores. HIGH PRESSURE PROCESSING OF FOOD 2016. [DOI: 10.1007/978-1-4939-3234-4_14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
28
|
Wacher-Rodarte MDC, Trejo-Muñúzuri TP, Montiel-Aguirre JF, Drago-Serrano ME, Gutiérrez-Lucas RL, Castañeda-Sánchez JI, Sainz-Espuñes T. Antibiotic resistance and multidrug-resistant efflux pumps expression in lactic acid bacteria isolated from pozol, a nonalcoholic Mayan maize fermented beverage. Food Sci Nutr 2015; 4:423-30. [PMID: 27247772 PMCID: PMC4867762 DOI: 10.1002/fsn3.304] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/18/2015] [Accepted: 09/21/2015] [Indexed: 01/22/2023] Open
Abstract
Pozol is a handcrafted nonalcoholic Mayan beverage produced by the spontaneous fermentation of maize dough by lactic acid bacteria. Lactic acid bacteria (LAB) are carriers of chromosomal encoded multidrug‐resistant efflux pumps genes that can be transferred to pathogens and/or confer resistance to compounds released during the fermentation process causing food spoiling. The aim of this study was to evaluate the antibiotic sensibility and the transcriptional expression of ABC‐type efflux pumps in LAB isolated from pozol that contributes to multidrug resistance. Analysis of LAB and Staphylococcus (S.) aureus ATCC 29213 and ATCC 6538 control strains to antibiotic susceptibility, minimal inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) to ethidium bromide were based in “standard methods” whereas the ethidium bromide efflux assay was done by fluorometric assay. Transcriptional expression of efflux pumps was analyzed by RT‐PCR. LAB showed antibiotic multiresistance profiles, moreover, Lactococcus (L.) lactis and Lactobacillus (L.) plantarum displayed higher ethidium bromide efflux phenotype than S. aureus control strains. Ethidium bromide resistance and ethidium bromide efflux phenotypes were unrelated with the overexpression of lmrD in L. lactics, or the underexpression of lmrA in L. plantarum and norA in S. aureus. These findings suggest that, moreover, the analyzed efflux pumps genes, other unknown redundant mechanisms may underlie the antibiotic resistance and the ethidium bromide efflux phenotype in L. lactis and L. plantarum. Phenotypic and molecular drug multiresistance assessment in LAB may improve a better selection of the fermentation starter cultures used in pozol, and to control the antibiotic resistance widespread and food spoiling for health safety.
Collapse
Affiliation(s)
- Maria Del Carmen Wacher-Rodarte
- Depto de Alimentos y Biotecnología Facultad de Química UNAM Ciudad Universitaria Coyoacán 04510 México Distrito Federal México
| | - Tanya Paulina Trejo-Muñúzuri
- Depto de Alimentos y Biotecnología Facultad de Química UNAM Ciudad Universitaria Coyoacán 04510 México Distrito Federal México
| | | | - Maria Elisa Drago-Serrano
- Depto. Sistemas Biológicos UAM-Xochimilco Calzada del Hueso No.1100, Coyoacan 04960 Mexico Distrito Federal México
| | - Raúl L Gutiérrez-Lucas
- Depto. Sistemas Biológicos UAM-Xochimilco Calzada del Hueso No.1100, Coyoacan 04960 Mexico Distrito Federal México
| | | | - Teresita Sainz-Espuñes
- Depto. Sistemas Biológicos UAM-Xochimilco Calzada del Hueso No.1100, Coyoacan 04960 Mexico Distrito Federal México
| |
Collapse
|
29
|
Microbiological quality and safety of smoothies treated in different pressure–temperature domains: effects on indigenous fruit microbiota and Listeria monocytogenes and their survival during storage. Eur Food Res Technol 2015. [DOI: 10.1007/s00217-015-2460-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
30
|
Syed QA, Buffa M, Guamis B, Saldo J. Factors Affecting Bacterial Inactivation during High Hydrostatic Pressure Processing of Foods: A Review. Crit Rev Food Sci Nutr 2015; 56:474-83. [DOI: 10.1080/10408398.2013.779570] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
31
|
Scolari G, Zacconi C, Busconi M, Lambri M. Effect of the combined treatments of high hydrostatic pressure and temperature on Zygosaccharomyces bailii and Listeria monocytogenes in smoothies. Food Control 2015. [DOI: 10.1016/j.foodcont.2014.07.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
32
|
Filannino P, Bai Y, Di Cagno R, Gobbetti M, Gänzle MG. Metabolism of phenolic compounds by Lactobacillus spp. during fermentation of cherry juice and broccoli puree. Food Microbiol 2014; 46:272-279. [PMID: 25475296 DOI: 10.1016/j.fm.2014.08.018] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/16/2014] [Accepted: 08/21/2014] [Indexed: 11/30/2022]
Abstract
This study aimed to investigate the metabolism of phenolic acids and flavonoids during lactic acid fermentation of cherry juice and broccoli puree for potential food and pharmaceutical purposes. When fermenting cherry juice and broccoli puree, Lactobacillus spp. exhibited strain-specific metabolism of phenolic acid derivatives. The metabolism of protocatechuic, caffeic and p-coumaric acids through phenolic acid decarboxylases and reductases differed between mMRS and cherry juice and broccoli puree. The synthesis of reduced compounds was the highest during food fermentations and the substrate seemed to modulate the metabolism of phenolic compounds. The reduction of phenolic acids involves a hydrogen donor and the re-oxidation of the reduced co-factor NADH, which may provide a metabolic advantage through NAD(+) regeneration. Quinic acid reduction may replace fructose and pyruvate as hydrogen acceptors, and it may provide an energetic advantage to heterofermentative bacteria when growing in broccoli puree lacking of fructose. This study demonstrated that phenolics metabolism may confer a selective advantage for lactobacilli in vegetable and fruit fermentation, and the metabolic routes are strongly dependent on the intrinsic factors of substrate. Fermented cherry juice and broccoli puree, due to the selected bacterial bioconversion pathways, are enriched in phenolic derivative with high human bioavailability and biological activity.
Collapse
Affiliation(s)
- Pasquale Filannino
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada; Department of Soil, Plant and Food Science, University of Bari Aldo Moro, Bari, Italy
| | - Yunpeng Bai
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Raffaela Di Cagno
- Department of Soil, Plant and Food Science, University of Bari Aldo Moro, Bari, Italy.
| | - Marco Gobbetti
- Department of Soil, Plant and Food Science, University of Bari Aldo Moro, Bari, Italy
| | - Michael G Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
33
|
Complete cell killing by applying high hydrostatic pressure for acellular vascular graft preparation. BIOMED RESEARCH INTERNATIONAL 2014; 2014:379607. [PMID: 24877088 PMCID: PMC4022071 DOI: 10.1155/2014/379607] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 12/13/2022]
Abstract
Pressure treatment has been developed in tissue engineering application. Although the tissue scaffold prepared by a ultrahydrostatic pressure treatment has been reported, an excessive pressure has a potential to disrupt a structure of extracellular matrix through protein denaturation. It is important to understand the suitable low-pressure condition and mechanisms for cell killing. In this study, cellular morphology, mitochondria activity, and membrane permeability of mammalian cells with various pressure treatments were investigated with in vitro models. When the cells were treated with a pressure of 100 MPa for 10 min, cell morphology and adherence were the same as an untreated cells. Dehydrogenase activity in mitochondria was almost the same as untreated cells. On the other hand, when the cells were treated with the pressure of more than 200 MPa, the cells did not adhere, and the dehydrogenase activity was completely suppressed. However, green fluorescence was observed in the live/dead staining images, and the cells were completely stained as red after above 500 MPa. That is, membrane permeability was disturbed with the pressure treatment of above 500 MPa. These results indicated that the pressure of 200 MPa for 10 min was enough to induce cell killing through inactivation of mitochondria activity.
Collapse
|
34
|
Gautier J, Passot S, Pénicaud C, Guillemin H, Cenard S, Lieben P, Fonseca F. A low membrane lipid phase transition temperature is associated with a high cryotolerance of Lactobacillus delbrueckii subspecies bulgaricus CFL1. J Dairy Sci 2013; 96:5591-602. [PMID: 23810590 DOI: 10.3168/jds.2013-6802] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 05/15/2013] [Indexed: 11/19/2022]
Abstract
The mechanisms of cellular damage that lactic acid bacteria incur during freeze-thaw processes have not been elucidated to date. Fourier transform infrared spectroscopy was used to investigate in situ the lipid phase transition behavior of the membrane of Lactobacillus delbrueckii ssp. bulgaricus CFL1 cells during the freeze-thaw process. Our objective was to relate the lipid membrane behavior to membrane integrity losses during freezing and to cell-freezing resistance. Cells were produced by using 2 different culture media: de Man, Rogosa, and Sharpe (MRS) broth (complex medium) or mild whey-based medium (minimal medium commonly used in the dairy industry), to obtain different membrane lipid compositions corresponding to different recovery rates of cell viability and functionality after freezing. The lipid membrane behavior studied by Fourier transform infrared spectroscopy was found to be different according to the cell lipid composition and cryotolerance. Freeze-resistant cells, exhibiting a higher content of unsaturated and cyclic fatty acids, presented a lower lipid phase transition temperature (Ts) during freezing (Ts=-8°C), occurring within the same temperature range as the ice nucleation, than freeze-sensitive cells (Ts=+22°C). A subzero value of lipid phase transition allowed the maintenance of the cell membrane in a relatively fluid state during freezing, thus facilitating water flux from the cell and the concomitant volume reduction following ice formation in the extracellular medium. In addition, the lipid phase transition of freeze-resistant cells occurred within a short temperature range, which could be ascribed to a reduced number of fatty acids, representing more than 80% of the total. This short lipid phase transition could be associated with a limited phenomenon of lateral phase separation and membrane permeabilization. This work highlights that membrane phase transitions occurring during freeze-thawing play a fundamental role in the cryotolerance of Lb. delbrueckii ssp. bulgaricus CFL1 cells.
Collapse
Affiliation(s)
- J Gautier
- INRA, UMR782, Génie et Microbiologie des Procédés Alimentaires, Thiverval-Grignon, France
| | | | | | | | | | | | | |
Collapse
|
35
|
Pilavtepe-Çelik M, Yousef A, Alpas H. Physiological changes of Escherichia coli O157:H7 and Staphylococcus aureus following exposure to high hydrostatic pressure. J Verbrauch Lebensm 2013. [DOI: 10.1007/s00003-013-0828-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
36
|
Gayán E, Torres JA, Paredes-Sabja D. Hurdle Approach to Increase the Microbial Inactivation by High Pressure Processing: Effect of Essential Oils. FOOD ENGINEERING REVIEWS 2012. [DOI: 10.1007/s12393-012-9055-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
37
|
Hofstetter S, Denter C, Winter R, McMullen LM, Gänzle MG. Use of the fluorescent probe LAURDAN to label and measure inner membrane fluidity of endospores of Clostridium spp. J Microbiol Methods 2012; 91:93-100. [PMID: 22884687 DOI: 10.1016/j.mimet.2012.07.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 07/17/2012] [Accepted: 07/17/2012] [Indexed: 11/29/2022]
Abstract
A method for measuring the fluidity of inner membranes of populations of endospores of Clostridium spp. with a fluorescent dye was developed. Cells of Clostridium beijerinckii ATCC 8260 and Clostridium sporogenes ATCC 7955 were allowed to sporulate in the presence of 6-dodecanoyl-2-dimethylaminonaphthalene (LAURDAN) on a soil-based media. Labeling of endospores with LAURDAN did not affect endospore viability. Removal of the outer membranes of endospores was done using a chemical treatment and confirmed using transmission electron microscopy (TEM). Two-photon confocal laser scanning microscopy (CLSM), and generalized polarization (GP) measurements were used to assess fluorescence of endospores. Lipid composition analysis of cells and endospores was done to determine whether differences in GP values are attributable to differences in membrane composition. Removal of the outer membranes of endospores did not significantly impact GP values. Decoated, labeled endospores of C. sporogenes ATCC 7955 and C. beijerinckii ATCC 8260 exhibited GP values of 0.77±0.031 and 0.74±0.027 respectively. Differences in ratios of fatty acids between cells and endospores are unlikely to be responsible for high GP values observed in endospores. These GP values indicate high levels of lipid order and the exclusion of water from within inner membranes of endospores.
Collapse
Affiliation(s)
- Simmon Hofstetter
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Alberta, Canada, T6G 2P5.
| | | | | | | | | |
Collapse
|
38
|
|
39
|
McKay AM, Linton M, Stirling J, Mackle A, Patterson MF. A comparative study of changes in the microbiota of apple juice treated by high hydrostatic pressure (HHP) or high pressure homogenisation (HPH). Food Microbiol 2011; 28:1426-31. [DOI: 10.1016/j.fm.2011.06.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 06/07/2011] [Accepted: 06/22/2011] [Indexed: 10/18/2022]
|
40
|
Zotta T, Guidone A, Tremonte P, Parente E, Ricciardi A. A comparison of fluorescent stains for the assessment of viability and metabolic activity of lactic acid bacteria. World J Microbiol Biotechnol 2011; 28:919-27. [DOI: 10.1007/s11274-011-0889-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 09/10/2011] [Indexed: 11/29/2022]
|
41
|
Sánchez-Maldonado AF, Schieber A, Gänzle MG. Structure-function relationships of the antibacterial activity of phenolic acids and their metabolism by lactic acid bacteria. J Appl Microbiol 2011; 111:1176-84. [PMID: 21895894 DOI: 10.1111/j.1365-2672.2011.05141.x] [Citation(s) in RCA: 219] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS To determine structure-function relationships of antibacterial phenolic acids and their metabolites produced by lactic acid bacteria (LAB). METHODS AND RESULTS Minimum inhibitory concentrations (MICs) of 6 hydroxybenzoic and 6 hydroxycinnamic acids were determined with Lactobacillus plantarum, Lactobacillus hammesii, Escherichia coli and Bacillus subtilis as indicator strains. The antibacterial activity of phenolic acids increased at lower pH. A decreasing number of hydroxyl groups enhanced the activity of hydroxybenzoic acids, but had minor effects on hydroxycinnamic acids. Substitution of hydroxyl groups with methoxy groups increased the activity of hydroxybenzoic, but not of hydroxycinnamic, acid. Metabolism of chlorogenic, caffeic, p-coumaric, ferulic, protocatechuic or p-hydroxybenzoic acids by L. plantarum, L. hammesii, Lactobacillus fermentum and Lactobacillus reuteri was analysed by LC-DAD-MS. Furthermore, MICs of substrates and metabolites were compared. Decarboxylated and/or reduced metabolites of phenolic acids had a lower activity than the substrates. Strain-specific metabolism of phenolic acids generally corresponded to resistance. CONCLUSIONS The influence of lipophilicity on the antibacterial activity of hydroxybenzoic acids is stronger than that of hydroxycinnamic acids. Metabolism of phenolic acids by LAB detoxifies phenolic acids. SIGNIFICANCE AND IMPACT OF THE STUDY Results allow the targeted selection of plant extracts for food preservation, and selection of starter cultures for fermented products.
Collapse
Affiliation(s)
- A F Sánchez-Maldonado
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | | | | |
Collapse
|
42
|
Microbiological food safety assessment of high hydrostatic pressure processing: A review. Lebensm Wiss Technol 2011. [DOI: 10.1016/j.lwt.2010.11.001] [Citation(s) in RCA: 259] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
43
|
Kim JA, Jung YS, Kim MY, Yang SY, Lee S, Kim YH. Protective effect of components isolated from Lindera erythrocarpa against oxidative stress-induced apoptosis of H9c2 cardiomyocytes. Phytother Res 2011; 25:1612-7. [PMID: 21412863 DOI: 10.1002/ptr.3465] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/27/2011] [Accepted: 02/08/2011] [Indexed: 11/08/2022]
Abstract
Eight compounds were isolated from the methanol fraction of Lindera erythrocarpa and assessed for their ability to protect H9c2 cardiomyocytes against oxidative stress-induced cell death. Three of the compounds significantly reduced the release of lactate dehydrogenase from H9c2 cardiomyocytes treated with buthionine-[S,R]-sulfoximine and reduced the uptake of propidium iodide by these cells. These effects were concentration-dependent. The three inhibitory compounds were identified as (-)-epicatechin, avicularin and quercitrin by spectroscopic techniques including one- and two-dimensional NMR and mass spectroscopy.
Collapse
Affiliation(s)
- Jeong Ah Kim
- College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea
| | | | | | | | | | | |
Collapse
|
44
|
Malinowska-Pańczyk E, Kołodziejska I, Saryczew M. Changes in bacterial cells induced by high pressure at subzero temperature. Syst Appl Microbiol 2011; 34:139-47. [PMID: 21316894 DOI: 10.1016/j.syapm.2010.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 09/28/2010] [Accepted: 09/29/2010] [Indexed: 11/28/2022]
Abstract
The aim of this study was to examine the effect of pressure treatment at 193MPa and -20°C on membrane damage, changes in activity of membrane-bound ATPases and degradation of nucleic acids. The experiments were carried out with three Escherichia coli strains, in the exponential and stationary phases of growth, and differing in sensitivity to pressure. All E. coli strains subjected to pressure in the exponential phase of growth were inactivated by 6 log cycles, independently of the strain, which was accompanied by a total loss of ability to plasmolyse, an increase in irreversible membrane permeability to PI, and a reduction of cellular ATP by more than 80%. After pressure treatment of stationary phase cells, the relationship between the inactivation level and the ability to plasmolyse was not as evident as in the case of exponential phase cells. Pressure treatment of two strains of E. coli K-12 and Ec160/59 in the stationary phase that decreased viability by no more than one log cycle led only to reversible permeabilization of bacterial membranes, while irreversible permeabilization was observed in the pressure sensitive E. coli IBA72 strain phase that was inactivated by 4.6 log cycles. The reduction of ATP and changes in ATPase activity after pressure treatment of tested E. coli strains in the stationary phase of growth depended on the stage of inactivation of the particular strain. Electrophoretic analysis showed degradation of RNA isolated after pressure treatment from cells of all E. coli strains tested in the exponential phase of growth. The changes of RNA induced by pressure were not visible in the case of cells in the stationary phase. The degradation of DNA isolated from pressure treated E. coli strains from the exponential as well as from the stationary phase of growth was not observed.
Collapse
Affiliation(s)
- Edyta Malinowska-Pańczyk
- Department of Food Chemistry, Technology and Biotechnology, Chemical Faculty, Gdansk University of Technology, G. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | | | | |
Collapse
|
45
|
Daryaei H, Coventry J, Versteeg C, Sherkat F. Combined pH and high hydrostatic pressure effects on Lactococcus starter cultures and Candida spoilage yeasts in a fermented milk test system during cold storage. Food Microbiol 2010; 27:1051-6. [DOI: 10.1016/j.fm.2010.07.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 07/01/2010] [Accepted: 07/08/2010] [Indexed: 10/19/2022]
|
46
|
Wu B, Shao H, Wang Z, Hu Y, Tang YJ, Jun YS. Viability and metal reduction of Shewanella oneidensis MR-1 under CO2 stress: implications for ecological effects of CO2 leakage from geologic CO2 sequestration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:9213-9218. [PMID: 21058700 DOI: 10.1021/es102299j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
To study potential ecological impacts of CO(2) leakage to shallow groundwater and soil/sediments from geologic CO(2) sequestration (GCS) sites, this work investigated the viability and metal reduction of Shewanella oneidensis MR-1 under CO(2) stress. While MR-1 could grow under high-pressure nitrogen gas (500 psi), the mix of 1% CO(2) with N(2) at total pressures of 15 or 150 psi significantly suppressed the growth of MR-1, compared to the N(2) control. When CO(2) partial pressures were over 15 psi, the growth of MR-1 stopped. The reduced bacterial viability was consistent with the pH decrease and cellular membrane damage under high pressure CO(2). After exposure to 150 psi CO(2) for 5 h, no viable cells survived, the cellular contents were released, and microscopy images confirmed significant cell structure deformation. However, after a relatively short exposure (25 min) to 150 psi CO(2), MR-1 could fully recover their growth within 24 h after the stress was removed, and the reduction of MnO(2) by MR-1 was observed right after the stress was removed. Furthermore, MR-1 survived better if the cells were aggregated rather than suspended, or if pH buffering minerals, such as calcite, were present. To predict the cell viability under different CO(2) pressures and exposure times, a two-parameter mathematical model was developed.
Collapse
Affiliation(s)
- Bing Wu
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | | | | | | | | | | |
Collapse
|
47
|
Effect of high hydrostatic pressure and high-pressure homogenisation on Lactobacillus plantarum inactivation kinetics and quality parameters of mandarin juice. Eur Food Res Technol 2010. [DOI: 10.1007/s00217-010-1381-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
48
|
Daryaei H, Coventry J, Versteeg C, Sherkat F. Effects of high pressure treatment on glycolytic enzymes of Lactococcus lactis subsp. lactis, Streptococcus thermophilus and Lactobacillus acidophilus. INNOV FOOD SCI EMERG 2010. [DOI: 10.1016/j.ifset.2009.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
49
|
Cao-Hoang L, Dumont F, Marechal PA, Gervais P. Inactivation of Escherichia coli and Lactobacillus plantarum in relation to membrane permeabilization due to rapid chilling followed by cold storage. Arch Microbiol 2010; 192:299-305. [PMID: 20191264 DOI: 10.1007/s00203-010-0555-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 01/22/2010] [Accepted: 01/28/2010] [Indexed: 10/19/2022]
Abstract
The relationship between membrane permeabilization and loss of viability by chilling depending on the chilling rate was investigated in two bacterial models: one Gram-positive bacterium, Lactobacillus plantarum, and one Gram-negative bacterium, Escherichia coli. Cells were cold shocked slowly (2 degrees C/min) or rapidly (2,000 degrees C/min) from physiological temperature to 0 degrees C and maintained at this temperature for up to 1 week. Loss of membrane integrity was assessed by the uptake of the fluorescent dye propidium iodide (PI). Cell death was found to be strongly dependent on the rate of temperature downshift to 0 degrees C. Prolonged incubation of cells after the chilling emphasized the effect of treatment on the cells, as the amount of cell death increased with the length of exposure to low temperature, particularly when cells were rapidly chilled. More than 5 and 3-log reductions in cell population were obtained with L. plantarum and E. coli after the rapid cold shock followed by 7-day storage, respectively. A correlation between cell inactivation and membrane permeabilization was demonstrated with both bacterial strains. Thus, loss of membrane integrity due to the chilling treatments was directly involved in the inactivation of vegetative bacterial cells.
Collapse
Affiliation(s)
- L Cao-Hoang
- Laboratoire de Génie des Procédés Microbiologiques et Alimentaires, AgroSup Dijon, France.
| | | | | | | |
Collapse
|
50
|
The relationship between membrane damage, release of protein and loss of viability in Escherichia coli exposed to high hydrostatic pressure. Int J Food Microbiol 2010; 137:214-20. [DOI: 10.1016/j.ijfoodmicro.2009.11.020] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 11/23/2009] [Accepted: 11/26/2009] [Indexed: 11/16/2022]
|