Topical Collection "Feature Papers in Food Microbiology"

A topical collection in Microorganisms (ISSN 2076-2607). This collection belongs to the section "Food Microbiology".

Editor

Prof. Dr. Giuseppe Comi
E-Mail Website
Collection Editor
Department of Food Science, University of Udine, Via Sondrio, 2/a, 33100 Udine, Italy
Interests: food microorganisms; spoilage; safety; hygiene; natural antimicrobial compounds; starters; food bioprotection and improvement; fermented foods and beverages; microbial ecology; toxin and mycotoxin; biomolecular methods
Special Issues, Collections and Topics in MDPI journals

Topical Collection Information

As follows from the title, this Topical Collection “Feature Papers in Food Microbiology” aims to collect high-quality research articles, short communications, and review articles in all fields of food microbiology. Since the aim of this Topical Collection is to illustrate, through selected works, frontier research in food microbiology, we encourage Editorial Board Members of the Food Microbiology Section of Microorganisms to contribute papers reflecting the latest progress in their research field, or to invite relevant experts and colleagues to do so.

Topics include, but are not limited to:

  • Food microbiology
  • Pathogenic microorganisms
  • Spoilage microorganisms
  • Interaction in food matrices
  • Detection (traditional and molecular methods, biosensors)
  • Starter cultures
  • Bacteriocins
  • Probiotics
  • Innovation in food protection
  • Antimicrobial resistance
  • Biotechnological aspects
  • Food antimicrobial compounds
  • Decontamination
  • Biofilms

Prof. Giuseppe Comi
Collection Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the collection website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Microorganisms is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (7 papers)

2020

Jump to: 2019

Article
In Vitro Probiotic Potential and Safety Evaluation (Hemolytic, Cytotoxic Activity) of Bifidobacterium Strains Isolated from Raw Camel Milk
Microorganisms 2020, 8(3), 354; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms8030354 - 02 Mar 2020
Cited by 14 | Viewed by 2233
Abstract
The present study was designed to isolate Bifidobacterium strains from raw camel milk and to investigate their probiotic characteristics. Among 35 isolates, 8 were identified as Gram-positive, catalase negative, non-spore forming, non-motile and V or Y shaped rods. B-2, B-5, B-11, B-19 and [...] Read more.
The present study was designed to isolate Bifidobacterium strains from raw camel milk and to investigate their probiotic characteristics. Among 35 isolates, 8 were identified as Gram-positive, catalase negative, non-spore forming, non-motile and V or Y shaped rods. B-2, B-5, B-11, B-19 and B-28 exhibited good survival at low pH and high bile salt concentration. Most of the isolates were resistant to nalidixic acid, fusidic acid, polymyxin B, neomycin, streptomycin, gentamicin, rifampicin and kanamycin. Furthermore, the production of exopolysaccharides (EPS), adhesion characteristics, antioxidant properties, antagonistic activities, nitrite reduction and cholesterol assimilation were also studied. Isolate B-11 was chosen because it exhibited most of the probiotic properties among all the tested isolates. It is identified as the member of Bifidobacterium longum group through 16S rRNA gene sequencing and named as B. longum B-11. B. longum B-11 was further selected for in vivo attachment to rat intestine and scanning electron micrographs revealed that attachment of a large number of rods shaped bacterial cell. Our findings suggest that B. longum B-11 processes excellent attributes to be used as potential probiotic in the development of functional probiotic food. Full article
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Article
Identification of Species and Subspecies of Lactic Acid Bacteria Present in Spanish Cheeses Type “Torta” by MALDI-TOF MS and pheS gene Analyses
Microorganisms 2020, 8(2), 301; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms8020301 - 21 Feb 2020
Cited by 9 | Viewed by 1737
Abstract
Several artisanal cheeses are elaborated in European countries, being commonly curdled with rennets of animal origin. However, in some Spanish regions some cheeses of type “Torta” are elaborated using Cynara cardunculus L. rennets. Two of these cheeses, “Torta del Casar” and “Torta de [...] Read more.
Several artisanal cheeses are elaborated in European countries, being commonly curdled with rennets of animal origin. However, in some Spanish regions some cheeses of type “Torta” are elaborated using Cynara cardunculus L. rennets. Two of these cheeses, “Torta del Casar” and “Torta de Trujillo”, are elaborated in Cáceres province with ewe’s raw milk and matured over at least 60 days without starters. In this work, we identified the lactic acid bacteria present in these cheeses using MALDI-TOF MS and pheS gene analyses, which showed they belong to the species Lactobacillus curvatus, Lactobacillus diolivorans, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactococcus lactis and Leuconostoc mesenteroides. The pheS gene analysis also allowed the identification of the subspecies La. plantarum subsp. plantarum, La. paracasei subsp. paracasei and Le. mesenteroides subsp. jonggajibkimchii. Low similarity values were found in this gene for some currently accepted subspecies of Lc. lactis and for the two subspecies of La. plantarum, and values near to 100% for the subspecies of Le. mesenteroides and La. paracasei. These results, which were confirmed by the calculated ANIb and dDDH values of their whole genomes, showed the need to revise the taxonomic status of these species and their subspecies. Full article
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Article
Interactions between Kazachstania humilis Yeast Species and Lactic Acid Bacteria in Sourdough
Microorganisms 2020, 8(2), 240; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms8020240 - 11 Feb 2020
Cited by 15 | Viewed by 1993
Abstract
Sourdoughs harbor simple microbial communities usually composed of a few prevailing lactic acid bacteria species (LAB) and yeast species. However, yeast and LAB found in sourdough have been described as highly diverse. Even if LAB and yeast associations have been widely documented, the [...] Read more.
Sourdoughs harbor simple microbial communities usually composed of a few prevailing lactic acid bacteria species (LAB) and yeast species. However, yeast and LAB found in sourdough have been described as highly diverse. Even if LAB and yeast associations have been widely documented, the nature of the interactions between them has been poorly described. These interactions define the composition and structure of sourdough communities, and therefore, the characteristics of the final bread product. In this study, the nature of the interactions between strains of two commonly found sourdough yeast species, Kazachstania humilis and Saccharomyces cerevisiae, and lactic acid bacteria isolated from sourdoughs has been analyzed. Population density analysis showed no evidence of positive interactions, but instead revealed neutral or negative asymmetric interaction outcomes. When in coculture, the yeasts´ population size decreased in the presence of LAB regardless of the strain, while the LAB´s population size was rarely influenced by the presence of yeasts. However, a higher maltose depletion was shown in maltose-negative K. humilis and maltose-positive obligately heterofermentative LAB cocultures compared to monocultures. In addition, tested pairs of obligately heterofermentative LAB and K. humilis strains leavened dough as much as couples of LAB and S. cerevisiae strains, while K. humilis strains never leavened dough as much as S. cerevisiae when in monoculture. Taken together, our results demonstrate that even if higher fermentation levels with increased maltose depletion were detected for K. humilis and obligately heterofermentative LAB pairs, these interactions cannot be ecologically classified as positive, leading us to rethink the established hypothesis of coexistence by facilitation in sourdoughs. Full article
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Article
Evaluation of Immunomodulatory Activities of the Heat-Killed Probiotic Strain Lactobacillus casei IMAU60214 on Macrophages In Vitro
Microorganisms 2020, 8(1), 79; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms8010079 - 07 Jan 2020
Cited by 7 | Viewed by 1561
Abstract
Most Lactobacillus species have beneficial immunological (“immunoprobiotic”) effects in the host. However, it is unclear how probiotic bacteria regulate immune responses. The present study investigated the effects of heat-killed Lactobacillus casei IMAU60214 on the activity of human monocyte-derived macrophages (MDMs). Human MDMs were [...] Read more.
Most Lactobacillus species have beneficial immunological (“immunoprobiotic”) effects in the host. However, it is unclear how probiotic bacteria regulate immune responses. The present study investigated the effects of heat-killed Lactobacillus casei IMAU60214 on the activity of human monocyte-derived macrophages (MDMs). Human MDMs were treated with heat-killed L. casei at a ratio (bacteria/MDM) of 50:1, 100:1, 250:1, and 500:1, and then evaluated for the following: NO production, by Griess reaction; phagocytosis of FITC-labeled Staphylococcus aureus particles; cytokine secretion profile (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-12p70, IL-10, and transforming growth factor (TGF)-β) by ELISA; and costimulatory molecule (CD80 and CD86) surface expression, by flow cytometry. Heat-killed L. casei IMAU60214 enhanced phagocytosis, NO production, cytokine release, and surface expression of CD80 and CD86 in a dose-dependent manner. All products were previously suppressed by pretreatment with a Toll-like receptor 2 (TLR2)-neutralizing antibody. Overall, our findings suggest that this probiotic strain promotes an M1-like pro-inflammatory phenotype through the TLR2 signaling pathway. These effects on macrophage phenotype help explain the probiotic efficacy of Lactobacillus and provide important information for the selection of therapeutic targets and treatments compatible with the immunological characteristics of this probiotic strain. Full article
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2019

Jump to: 2020

Article
Schizosaccharomyces pombe Can Reduce Acetic Acid Produced by Baijiu Spontaneous Fermentation Microbiota
Microorganisms 2019, 7(12), 606; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms7120606 - 22 Nov 2019
Cited by 7 | Viewed by 1944
Abstract
The spontaneous fermentation of alcoholic beverage is a bioprocess donated by microbiota with complex stress environments. Among various microbes, non-Saccharomyces yeasts have high stress tolerance and significantly affect the taste and quality of products in process. Although many researchers have focused on [...] Read more.
The spontaneous fermentation of alcoholic beverage is a bioprocess donated by microbiota with complex stress environments. Among various microbes, non-Saccharomyces yeasts have high stress tolerance and significantly affect the taste and quality of products in process. Although many researchers have focused on the influence of acid stress, the mechanism of non-Saccharomyces yeasts to tolerant stress remains unclear in microbiota. To bridge the gap, we constructed in situ and in vitro studies to explore the reduction pathway of acetic acid in non-Saccharomyces yeasts. In this study, we found Schizosaccharomyces pombe has special capacities to resist 10 g/L acetic acid in laboratory cultures and decrease the average concentration of acetic acid from 9.62 to 6.55 g/kg fermented grains in Chinese Maotai-flavor liquor (Baijiu) production. Moreover, Schi. pombe promoted metabolic level of mevalonate pathway (high expressions of gene ACCAT1, HMGCS1, and HMGCR1) to degrade a high concentration of acetic acid. Meanwhile, Schi. pombe also improved the concentration of mevalonic acid that is the precursor of terpenes to enhance the taste and quality of Baijiu. Overall, the synchronicity of reduction and generation in Schi. pombe advances the current knowledge to guide more suitable strategies for mechanism studies of non-Saccharomyces yeasts in fermented industries of alcoholic beverages. Full article
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Article
Elucidating Escherichia Coli O157:H7 Colonization and Internalization in Cucumbers Using an Inverted Fluorescence Microscope and Hyperspectral Microscopy
Microorganisms 2019, 7(11), 499; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms7110499 - 28 Oct 2019
Cited by 3 | Viewed by 1358
Abstract
Contamination of fresh cucumbers (Cucumis sativus L.) with Escherichia coli O157:H7 can impact the health of consumers. Despite this, the pertinent mechanisms underlying E. coli O157:H7 colonization and internalization remain poorly documented. Herein we aimed to elucidate these mechanisms in cucumbers using [...] Read more.
Contamination of fresh cucumbers (Cucumis sativus L.) with Escherichia coli O157:H7 can impact the health of consumers. Despite this, the pertinent mechanisms underlying E. coli O157:H7 colonization and internalization remain poorly documented. Herein we aimed to elucidate these mechanisms in cucumbers using an inverted fluorescence microscope and hyperspectral microscopy. We observed that E. coli O157:H7 primarily colonized around the stomata on cucumber epidermis without invading the internal tissues of intact cucumbers. Once the bacterial cells had infiltrated into the internal tissues, they colonized the cucumber placenta and vascular bundles (xylem vessels, in particular), and also migrated along the xylem vessels. Moreover, the movement rate of E. coli O157:H7 from the stalk to the flower bud was faster than that from the flower bud to the stalk. We then used hyperspectral microscope imaging to categorize the infiltrated and uninfiltrated areas with high accuracy using the spectral angle mapper (SAM) classification method, which confirmed the results obtained upon using the inverted fluorescence microscope. We believe that our results are pivotal for developing science-based food safety practices, interventions for controlling E. coli O157:H7 internalization, and new methods for detecting E. coli O157:H7-plant interactions. Full article
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Article
Antimicrobial and Anti-Inflammatory Lingonberry Mouthwash—A Clinical Pilot Study in the Oral Cavity
Microorganisms 2019, 7(9), 331; https://0-doi-org.brum.beds.ac.uk/10.3390/microorganisms7090331 - 08 Sep 2019
Cited by 5 | Viewed by 1638
Abstract
Fermented lingonberry juice was designed to be used as a mouthwash. Our aim was to study the antimicrobial and anti-inflammatory effects of the mouthwash in the oral cavity. A clinical study of 30 adult participants was performed. A total of 20 participants used [...] Read more.
Fermented lingonberry juice was designed to be used as a mouthwash. Our aim was to study the antimicrobial and anti-inflammatory effects of the mouthwash in the oral cavity. A clinical study of 30 adult participants was performed. A total of 20 participants used 10 mL of the mouthwash twice daily for two weeks and 10 participants used 20 mL twice daily for one week. Streptococcus mutans, Candida and Lactobacilli were cultivated at the beginning, after the mouthwash period and after a washout period. At the same timepoints an additional oral mouthrinse was collected for chair-side/point-of-care (POC)-PerioSafe®/OraLyzer® aMMP-8 quantitative on-line evaluation, and an oral clinical investigation was performed. Mean Streptococcus mutans and Candida counts, visible plaque index (VPI) and bleeding on probing (BOP) were reduced, and Lactobacilli counts increased during the lingonberry mouthwash period. The aMMP-8 mouthrinses showed reduced values in both test groups when compared to the startpoint. The mouthrinse aMMP-8 reduction correlated with the reductions in microbial counts, VPI and BOP. Based on the results, fermented lingonberry juice seems a promising aid in oral homecare, diminishing the microbial and related proinflammatory burden by balancing the oral microbial flora and gradually lowering the inflammatory load in the oral cavity. Full article
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