Special Issue "Microbial Activity in Food"

A special issue of Microorganisms (ISSN 2076-2607). This special issue belongs to the section "Food Microbiology".

Deadline for manuscript submissions: closed (31 March 2016)

Special Issue Editor

Guest Editor
Prof. Giuseppe Comi

Department of Food Science, University of Udine, Via Sondrio, 2/a, 33100 Udine, Italy
Website | E-Mail
Phone: +39 3389918561
Fax: +39-432-558-130
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 Issue Information

Dear Colleagues,

 

Microorganisms for food improvement and safety are the most widespread and widely studied. In particular, studies in the ecology of microorganisms by molecular methods have increased in order to find out their importance regarding spoiling, safety or ripening of food products. Every food has indexes of freshness, quality and technological problems due to microorganisms. Study on public health issues and on particular microorganisms and opportunistic pathogens is necessary to determine food hygienic quality. Research and selections of microorganisms as a starter for fermentations or bioprotections of food are of great interest to improve their sensorial characteristics and safety. Food production needs fast and simple methods to detect the hygienic quality of food. Consequently, biomolecular methods represent a real answer to this request. Finally, the studies of activity of probiotic lactic acid bacteria and yeasts are necessary to combat nutritional defects and microbial diseases.

This issue will publish papers on all aspects of microorganisms activity in food.

Professor Giuseppe Comi
Guest Editor

Manuscript Submission Information

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Keywords

  • microorganisms
  • activity
  • food production
  • food safety
  • food protection
  • food spoilage
  • food improvement
  • toxin and mycotoxin
  • essential oil

Published Papers (14 papers)

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Research

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Open AccessArticle Phage Inactivation of Listeria monocytogenes on San Daniele Dry-Cured Ham and Elimination of Biofilms from Equipment and Working Environments
Microorganisms 2016, 4(1), 4; https://doi.org/10.3390/microorganisms4010004
Received: 28 October 2015 / Revised: 10 December 2015 / Accepted: 17 December 2015 / Published: 5 January 2016
Cited by 11 | PDF Full-text (844 KB) | HTML Full-text | XML Full-text
Abstract
The anti-listerial activity of generally recognized as safe (GRAS) bacteriophage Listex P100 (phage P100) was demonstrated in broths and on the surface of slices of dry-cured ham against 5 strains or serotypes (i.e., Scott A, 1/2a, 1/2b, and 4b) of Listeria [...] Read more.
The anti-listerial activity of generally recognized as safe (GRAS) bacteriophage Listex P100 (phage P100) was demonstrated in broths and on the surface of slices of dry-cured ham against 5 strains or serotypes (i.e., Scott A, 1/2a, 1/2b, and 4b) of Listeria monocytogenes. In a broth model system, phage P100 at a concentration equal to or greater than 7 log PFU/mL completely inhibited 2 log CFU/cm2 or 3 log CFU/cm2 of L. monocytogenes growth at 30 °C. The temperature (4, 10, 20 °C) seemed to influence P100 activity; the best results were obtained at 4 °C. On dry-cured ham slices, a P100 concentration ranging from 5 to 8 log PFU/cm2 was required to obtain a significant reduction in L. monocytogenes. At 4, 10, and 20 °C, an inoculum of 8 log PFU/cm2 was required to completely eliminate 2 log L. monocytogenes/cm2 and to reach the absence in 25 g product according to USA food law. Conversely, it was impossible to completely eradicate L. monocytogenes with an inoculum of approximately of 3.0 and 4.0 log CFU/cm2 and with a P100 inoculum ranging from 1 to 7 log PFU/cm2. P100 remained stable on dry-cured ham slices over a 14-day storage period, with only a marginal loss of 0.2 log PFU/cm2 from an initial phage treatment of approximately 8 log PFU/cm2. Moreover, phage P100 eliminated free L. monocytogenes cells and biofilms on the machinery surfaces used for dry-cured ham production. These findings demonstrate that the GRAS bacteriophage Listex P100 at level of 8 log PFU/cm2 is listericidal and useful for reducing the L. monocytogenes concentration or eradicating the bacteria from dry-cured ham. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessArticle Bioactivities of Ketones Terpenes: Antifungal Effect on F. verticillioides and Repellents to Control Insect Fungal Vector, S. zeamais
Microorganisms 2015, 3(4), 851-865; https://doi.org/10.3390/microorganisms3040851
Received: 14 August 2015 / Revised: 25 September 2015 / Accepted: 2 November 2015 / Published: 12 November 2015
Cited by 3 | PDF Full-text (1065 KB) | HTML Full-text | XML Full-text
Abstract
Maize is one the most important staple foods in the world. However, numerous pests, such as fungal pathogens, e.g., Fusarium verticillioides, and insects, such as Sitophlilus zeamais, attack maize grains during storage. Many F. verticillioides strains produce fumonisins, one of the most [...] Read more.
Maize is one the most important staple foods in the world. However, numerous pests, such as fungal pathogens, e.g., Fusarium verticillioides, and insects, such as Sitophlilus zeamais, attack maize grains during storage. Many F. verticillioides strains produce fumonisins, one of the most important mycotoxin that causes toxic effects on human and animal health. This situation is aggravated by the insect fungal vector, Sitophlilus zeamais, which contributes to the dispersal of fungal spores, and through feeding damage, provide entry points for fungal infections. The aim of this study was to evaluate in vitro bioassays, the antifungal activity on F. verticillioides M3125 and repellent effects against S. zeamais of ketone terpenes. In addition, we performed Quantitative structure–activity relationship (Q-SAR) studies between physico-chemical properties of ketone terpenes and the antifungal effect. Thymoquinone was the most active compound against F. verticillioides (Minimum Inhibitory Concentration, MIC: 0.87) affecting the lag phase and the growth rate showing a total inhibition of growth at concentration higher than 2 mM (p < 0.05). The Q-SAR model revealed that the antifungal activity of ketone compounds is related to the electronic descriptor, Pi energy. Thymoquinone showed a strong repellent effect (−77.8 ± 8.5, p < 0.001) against S. zeamais. These findings make an important contribution to the search for new compounds to control two stored pests of maize. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessArticle The Potential of the Yeast Debaryomyces hansenii H525 to Degrade Biogenic Amines in Food
Microorganisms 2015, 3(4), 839-850; https://doi.org/10.3390/microorganisms3040839
Received: 3 July 2015 / Revised: 25 October 2015 / Accepted: 2 November 2015 / Published: 6 November 2015
Cited by 8 | PDF Full-text (557 KB) | HTML Full-text | XML Full-text
Abstract
Twenty-six yeasts from different genera were investigated for their ability to metabolize biogenic amines. About half of the yeast strains produced one or more different biogenic amines, but some strains of Debaryomyces hansenii and Yarrowia lipolytica were also able to degrade such compounds. [...] Read more.
Twenty-six yeasts from different genera were investigated for their ability to metabolize biogenic amines. About half of the yeast strains produced one or more different biogenic amines, but some strains of Debaryomyces hansenii and Yarrowia lipolytica were also able to degrade such compounds. The most effective strain D. hanseniii H525 metabolized a broad spectrum of biogenic amines by growing and resting cells. Degradation of biogenic amines by this yeast isolate could be attributed to a peroxisomal amine oxidase activity. Strain H525 may be useful as a starter culture to reduce biogenic amines in fermented food. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessArticle Movement of Salmonella serovar Typhimurium and E. coli O157:H7 to Ripe Tomato Fruit Following Various Routes of Contamination
Microorganisms 2015, 3(4), 809-825; https://doi.org/10.3390/microorganisms3040809
Received: 14 July 2015 / Revised: 28 October 2015 / Accepted: 2 November 2015 / Published: 5 November 2015
Cited by 2 | PDF Full-text (985 KB) | HTML Full-text | XML Full-text
Abstract
Salmonella serovars have been associated with the majority of foodborne illness outbreaks involving tomatoes, and E. coli O157:H7 has caused outbreaks involving other fresh produce. Contamination by both pathogens has been thought to originate from all points of the growing and distribution process. [...] Read more.
Salmonella serovars have been associated with the majority of foodborne illness outbreaks involving tomatoes, and E. coli O157:H7 has caused outbreaks involving other fresh produce. Contamination by both pathogens has been thought to originate from all points of the growing and distribution process. To determine if Salmonella serovar Typhimurium and E. coli O157:H7 could move to the mature tomato fruit of different tomato cultivars following contamination, three different contamination scenarios (seed, leaf, and soil) were examined. Following contamination, each cultivar appeared to respond differently to the presence of the pathogens, with most producing few fruit and having overall poor health. The Micro-Tom cultivar, however, produced relatively more fruit and E. coli O157:H7 was detected in the ripe tomatoes for both the seed- and leaf- contaminated plants, but not following soil contamination. The Roma cultivar produced fewer fruit, but was the only cultivar in which E. coli O157:H7 was detected via all three routes of contamination. Only two of the five cultivars produced tomatoes following seed-, leaf-, and soil- contamination with Salmonella Typhimurium, and no Salmonella was found in any of the tomatoes. Together these results show that different tomato cultivars respond differently to the presence of a human pathogen, and for E. coli O157:H7, in particular, tomato plants that are either contaminated as seeds or have a natural opening or a wound, that allows bacteria to enter the leaves can result in plants that have the potential to produce tomatoes that harbor internalized pathogenic bacteria. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessArticle Evaluation of Potential Effects of NaCl and Sorbic Acid on Staphylococcal Enterotoxin A Formation
Microorganisms 2015, 3(3), 551-566; https://doi.org/10.3390/microorganisms3030551
Received: 18 June 2015 / Revised: 3 August 2015 / Accepted: 1 September 2015 / Published: 17 September 2015
Cited by 3 | PDF Full-text (931 KB) | HTML Full-text | XML Full-text
Abstract
The prophage-encoded staphylococcal enterotoxin A (SEA) is recognized as the main cause of staphylococcal food poisoning (SFP), a common foodborne intoxication disease, caused by Staphylococcus aureus. Studies on the production of SEA suggest that activation of the SOS response and subsequent prophage [...] Read more.
The prophage-encoded staphylococcal enterotoxin A (SEA) is recognized as the main cause of staphylococcal food poisoning (SFP), a common foodborne intoxication disease, caused by Staphylococcus aureus. Studies on the production of SEA suggest that activation of the SOS response and subsequent prophage induction affect the regulation of the sea gene and the SEA produced, increasing the risk for SFP. The present study aims to evaluate the effect of NaCl and sorbic acid, in concentrations relevant to food production, on SOS response activation, prophage induction and SEA production. The impact of stress was initially evaluated on steady state cells for a homogenous cell response. NaCl 2% was found to activate the SOS response, i.e., recA expression, and trigger prophage induction, in a similar way as the phage-inducer mitomycin C. In contrast, sorbic acid decreased the pH of the culture to a level where prophage induction was probably suppressed, even when combined with NaCl stress. The impact of previous physiological state of the bacteria was also addressed on cells pre-exposed to NaCl, and was found to potentially affect cell response upon exposure to further stress. The results obtained highlight the possible SFP-related risks arising from the use of preservatives during food processing. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessArticle Effect of Lemongrass Essential Oil Vapors on Microbial Dynamics and Listeria monocytogenes Survival on Rocket and Melon Stored under Different Packaging Conditions and Temperatures
Microorganisms 2015, 3(3), 535-550; https://doi.org/10.3390/microorganisms3030535
Received: 27 July 2015 / Accepted: 1 September 2015 / Published: 9 September 2015
Cited by 2 | PDF Full-text (742 KB) | HTML Full-text | XML Full-text
Abstract
The aim of the present study was to examine the effect of lemongrass essential oil vapors on the dynamics of surface microbiota and L. monocytogenes growth on rocket and melon under different packaging conditions and storage temperature. For that purpose, rocket and [...] Read more.
The aim of the present study was to examine the effect of lemongrass essential oil vapors on the dynamics of surface microbiota and L. monocytogenes growth on rocket and melon under different packaging conditions and storage temperature. For that purpose, rocket and melon were placed on Expanded Polystyrene (EPS) trays, sprayed with L. monocytogenes to a population of 4.5–5.0 log CFU·g−1, packaged using microperforated Oriented Polypropylene (OPP) film in either air or Microperforated Active Modified Atmosphere (MAMA) (initial atmosphere 5% O2, 10% CO2) including a Whatman paper containing the essential oil, without contact with the product, and stored at 0, 5, 10, and 15 °C. Application of lemongrass exhibited a bactericidal effect on enterococci and a fungistatic effect on yeast-mould populations but only during air storage of rocket. The former took place at all temperatures and the latter only at 10 and 15 °C. No effect on shelf life of both products was recorded. However, an important effect on the sensorial properties was observed; during the first 4–5 days of storage both products were organoleptically unacceptable. Regarding MAMA packaging, it affected only Pseudomonas spp. population resulting in a reduction of 1–2 log CFU·g−1 in both products. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
Open AccessArticle Assessment of the Factors Contributing to the Growth or Spoilage of Meyerozyma guilliermondii in Organic Yogurt: Comparison of Methods for Strain Differentiation
Microorganisms 2015, 3(3), 428-440; https://doi.org/10.3390/microorganisms3030428
Received: 9 July 2015 / Revised: 30 July 2015 / Accepted: 7 August 2015 / Published: 19 August 2015
Cited by 5 | PDF Full-text (642 KB) | HTML Full-text | XML Full-text
Abstract
In this work we analyze the spoiling potential of Meyerozyma guilliermondii in yogurt. The analysis was based on contaminated samples sent to us by an industrial laboratory over two years. All the plain and fruit yogurt packages were heavily contaminated by yeasts, but [...] Read more.
In this work we analyze the spoiling potential of Meyerozyma guilliermondii in yogurt. The analysis was based on contaminated samples sent to us by an industrial laboratory over two years. All the plain and fruit yogurt packages were heavily contaminated by yeasts, but only the last ones, containing fermentable sugars besides lactose, were spoiled by gas swelling. These strains were unable to grow and ferment lactose (as the type strain); they did grow on lactate plus galactose, fermented glucose and sucrose, and galactose (weakly), but did not compete with lactic acid bacteria for lactose. This enables them to grow in any yogurt, although only those with added jam were spoiled due to the fermentation of the fruit sugars. Fermentation, but not growth, was strongly inhibited at 8 °C. In consequence, in plain yogurt as well as in any yogurt maintained at low temperature, yeast contamination would not be detected by the consumer. The risk could be enhanced because the species has been proposed for biological control of fungal infections in organic agriculture. The combination of the IGS PCR-RFLP (amplification of the intergenic spacer region of rDNA followed by restriction fragment length polymorphism analysis) method and mitochondrial DNA-RFLP makes a good tool to trace and control the contamination by M. guilliermondii. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessArticle Comparison of Microbiological and Probiotic Characteristics of Lactobacilli Isolates from Dairy Food Products and Animal Rumen Contents
Microorganisms 2015, 3(2), 198-212; https://doi.org/10.3390/microorganisms3020198
Received: 9 March 2015 / Revised: 23 March 2015 / Accepted: 25 March 2015 / Published: 15 April 2015
Cited by 12 | PDF Full-text (688 KB) | HTML Full-text | XML Full-text
Abstract
Lactobacilli are employed in probiotic food preparations and as feed additives in poultry and livestock, due to health benefits associated with their consumption. The objective of this study was to evaluate and compare the probiotic potential of ten lactobacilli strains isolated from commercial [...] Read more.
Lactobacilli are employed in probiotic food preparations and as feed additives in poultry and livestock, due to health benefits associated with their consumption. The objective of this study was to evaluate and compare the probiotic potential of ten lactobacilli strains isolated from commercial dairy food products and animal rumen contents in New Zealand. Genetic identification of the isolates revealed that all belonged to the genus Lactobacillus, specifically the species L. reuteri, L. rhamnosus and L. plantarum. All isolates did not show any haemolytic behaviour. Isolates of dairy origin showed better tolerance to low pH stress. On the other hand, rumen isolates exhibited a higher tolerance to presence of bile salts. All isolates exhibited resistance to aminoglycoside antibiotics, however most were sensitive to ampicillin. Isolates of rumen origin demonstrated a higher inhibitory effect on Listeria monocytogenes, Enterobacter aerogenes and Salmonella menston. Bacterial adherence of all isolates increased with a decrease in pH. This screening study on lactobacilli isolates has assessed and identified potential probiotic candidates for further evaluation. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessArticle Isolation and Taxonomic Identity of Bacteriocin-Producing Lactic Acid Bacteria from Retail Foods and Animal Sources
Microorganisms 2015, 3(1), 80-93; https://doi.org/10.3390/microorganisms3010080
Received: 30 January 2015 / Revised: 2 March 2015 / Accepted: 9 March 2015 / Published: 19 March 2015
Cited by 7 | PDF Full-text (1086 KB) | HTML Full-text | XML Full-text
Abstract
Bacteriocin-producing (Bac+) lactic acid bacteria (LAB) were isolated from a variety of food products and animal sources. Samples were enriched in de Man, Rogosa, and Sharpe (MRS) Lactocilli broth and plated onto MRS agar plates using a “sandwich overlay” technique. Inhibitory [...] Read more.
Bacteriocin-producing (Bac+) lactic acid bacteria (LAB) were isolated from a variety of food products and animal sources. Samples were enriched in de Man, Rogosa, and Sharpe (MRS) Lactocilli broth and plated onto MRS agar plates using a “sandwich overlay” technique. Inhibitory activity was detected by the “deferred antagonism” indicator overlay method using Listeria monocytogenes as the primary indicator organism. Antimicrobial activity against L. monocytogenes was detected by 41 isolates obtained from 23 of 170 food samples (14%) and 11 of 110 samples from animal sources (10%) tested. Isolated Bac+ LAB included Lactococcus lactis, Lactobacillus curvatus, Carnobacterium maltaromaticum, Leuconostoc mesenteroides, and Pediococcus acidilactici, as well as Enterococcus faecium, Enterococcus faecalis, Enterococcus hirae, and Enterococcus thailandicus. In addition to these, two Gram-negative bacteria were isolated (Serratia plymuthica, and Serratia ficaria) that demonstrated inhibitory activity against L. monocytogenes, Staphylococcus aureus, and Enterococcus faecalis (S. ficaria additionally showed activity against Salmonella Typhimurium). These data continue to demonstrate that despite more than a decade of antimicrobial interventions on meats and produce, a wide variety of food products still contain Bac+ microbiota that are likely eaten by consumers and may have application as natural food preservatives. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessArticle Fumaric Acid and Slightly Acidic Electrolyzed Water Inactivate Gram Positive and Gram Negative Foodborne Pathogens
Microorganisms 2015, 3(1), 34-46; https://doi.org/10.3390/microorganisms3010034
Received: 29 November 2014 / Accepted: 3 February 2015 / Published: 12 February 2015
Cited by 10 | PDF Full-text (504 KB) | HTML Full-text | XML Full-text
Abstract
Sanitizing effectiveness of slightly acidic electrolyzed water (SAEW) and fumaric acid (FA) at different dipping temperatures (25–60 °C), times (1–5 min), and concentrations (5–30 ppm for SAEW and 0.125%–0.5% for FA) on pure cultures of two Gram positive pathogens Staphylococcus aureus (SA) and [...] Read more.
Sanitizing effectiveness of slightly acidic electrolyzed water (SAEW) and fumaric acid (FA) at different dipping temperatures (25–60 °C), times (1–5 min), and concentrations (5–30 ppm for SAEW and 0.125%–0.5% for FA) on pure cultures of two Gram positive pathogens Staphylococcus aureus (SA) and Listeria monocytogenes (LM) and two Gram negative pathogens Escherichia coli O157:H7 (EC) and Salmonella Typhimurium (ST) was evaluated. FA (0.25%) showed the strongest sanitizing effect, demonstrating complete inactivation of EC, ST, and LM, while SA was reduced by 3.95–5.76 log CFU/mL at 25–60 °C, respectively, after 1 min of treatment. For SAEW, the complete inactivation was obtained when available chlorine concentration was increased to 20 ppm at 40 °C for 3 and 5 min. Moreover, Gram positive pathogens have been shown to resist to all treatment trends more than Gram negative pathogens throughout this experiment. Regardless of the different dipping temperatures, concentrations, and times, FA treatment was more effective than treatment with SAEW for reduction of foodborne pathogens. This study demonstrated that application of FA in food systems may be useful as a method for inactivation of foodborne pathogens. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessArticle Identification of Multiple Bacteriocins in Enterococcus spp. Using an Enterococcus-Specific Bacteriocin PCR Array
Microorganisms 2015, 3(1), 1-16; https://doi.org/10.3390/microorganisms3010001
Received: 11 January 2015 / Revised: 16 January 2015 / Accepted: 21 January 2015 / Published: 4 February 2015
Cited by 10 | PDF Full-text (982 KB) | HTML Full-text | XML Full-text
Abstract
Twenty-two bacteriocin-producing Enterococcus isolates obtained from food and animal sources, and demonstrating activity against Listeria monocytogenes, were screened for bacteriocin-related genes using a bacteriocin PCR array based on known enterococcal bacteriocin gene sequences in the NCBI GenBank database. The 22 bacteriocin-positive (Bac+) [...] Read more.
Twenty-two bacteriocin-producing Enterococcus isolates obtained from food and animal sources, and demonstrating activity against Listeria monocytogenes, were screened for bacteriocin-related genes using a bacteriocin PCR array based on known enterococcal bacteriocin gene sequences in the NCBI GenBank database. The 22 bacteriocin-positive (Bac+) enterococci included En. durans (1), En. faecalis (4), En. faecium (12), En. hirae (3), and En. thailandicus (2). Enterocin A (entA), enterocins mr10A and mr10B (mr10AB), and bacteriocin T8 (bacA) were the most commonly found structural genes in order of decreasing prevalence. Forty-five bacteriocin genes were identified within the 22 Bac+ isolates, each containing at least one of the screened structural genes. Of the 22 Bac+ isolates, 15 possessed two bacteriocin genes, seven isolates contained three different bacteriocins, and three isolates contained as many as four different bacteriocin genes. These results may explain the high degree of bactericidal activity observed with various Bac+ Enterococcus spp. Antimicrobial activity against wild-type L. monocytogenes and a bacteriocin-resistant variant demonstrated bacteriocins having different modes-of-action. Mixtures of bacteriocins, especially those with different modes-of-action and having activity against foodborne pathogens, such as L. monocytogenes, may play a promising role in the preservation of food. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Review

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Open AccessReview Alicyclobacillus spp.: New Insights on Ecology and Preserving Food Quality through New Approaches
Microorganisms 2015, 3(4), 625-640; https://doi.org/10.3390/microorganisms3040625
Received: 27 July 2015 / Accepted: 29 September 2015 / Published: 10 October 2015
Cited by 4 | PDF Full-text (251 KB) | HTML Full-text | XML Full-text
Abstract
Alicyclobacillus spp. includes spore-forming and thermo-acidophilic microorganisms, usually recovered from soil, acidic drinks, orchards and equipment from juice producers. The description of the genus is generally based on the presence of ω-fatty acids in the membrane, although some newly described species do not [...] Read more.
Alicyclobacillus spp. includes spore-forming and thermo-acidophilic microorganisms, usually recovered from soil, acidic drinks, orchards and equipment from juice producers. The description of the genus is generally based on the presence of ω-fatty acids in the membrane, although some newly described species do not possess them. The genus includes different species and sub-species, but A. acidoterrestris is generally regarded as the most important spoiler for acidic drinks and juices. The main goal of this review is a focus on the ecology of the genus, mainly on the species A. acidoterrestris, with a special emphasis on the different phenotypic properties and genetic traits, along with the correlation among them and with the primary source of isolation. Finally, the last section of the review reports on some alternative approaches to heat treatments (natural compounds and other chemical treatments) to control and/or reduce the contamination of food by Alicyclobacillus. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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Open AccessReview Bioprotective Role of Yeasts
Microorganisms 2015, 3(4), 588-611; https://doi.org/10.3390/microorganisms3040588
Received: 30 July 2015 / Accepted: 29 September 2015 / Published: 10 October 2015
Cited by 22 | PDF Full-text (688 KB) | HTML Full-text | XML Full-text
Abstract
The yeasts constitute a large group of microorganisms characterized by the ability to grow and survive in different and stressful conditions and then to colonize a wide range of environmental and human ecosystems. The competitive traits against other microorganisms have attracted increasing attention [...] Read more.
The yeasts constitute a large group of microorganisms characterized by the ability to grow and survive in different and stressful conditions and then to colonize a wide range of environmental and human ecosystems. The competitive traits against other microorganisms have attracted increasing attention from scientists, who proposed their successful application as bioprotective agents in the agricultural, food and medical sectors. These antagonistic activities rely on the competition for nutrients, production and tolerance of high concentrations of ethanol, as well as the synthesis of a large class of antimicrobial compounds, known as killer toxins, which showed clearly a large spectrum of activity against food spoilage microorganisms, but also against plant, animal and human pathogens. This review describes the antimicrobial mechanisms involved in the antagonistic activity, their applications in the processed and unprocessed food sectors, as well as the future perspectives in the development of new bio-drugs, which may overcome the limitations connected to conventional antimicrobial and drug resistance. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
Open AccessReview Live Yeast and Yeast Cell Wall Supplements Enhance Immune Function and Performance in Food-Producing Livestock: A Review †,
Microorganisms 2015, 3(3), 417-427; https://doi.org/10.3390/microorganisms3030417
Received: 26 May 2015 / Revised: 17 July 2015 / Accepted: 29 July 2015 / Published: 7 August 2015
Cited by 21 | PDF Full-text (373 KB) | HTML Full-text | XML Full-text
Abstract
More livestock producers are seeking natural alternatives to antibiotics and antimicrobials, and searching for supplements to enhance growth performance, and general animal health and well-being. Some of the compounds currently being utilized and studied are live yeast and yeast-based products derived from the [...] Read more.
More livestock producers are seeking natural alternatives to antibiotics and antimicrobials, and searching for supplements to enhance growth performance, and general animal health and well-being. Some of the compounds currently being utilized and studied are live yeast and yeast-based products derived from the strain Saccharomyces cerevisiae. These products have been reported to have positive effects both directly and indirectly on the immune system and its subsequent biomarkers, thereby mitigating negative effects associated with stress and disease. These yeast-based products have also been reported to simultaneously enhance growth and performance by enhancing dry matter intake (DMI) and average daily gain (ADG) perhaps through the establishment of a healthy gastrointestinal tract. These products may be especially useful in times of potential stress such as during birth, weaning, early lactation, and during the receiving period at the feedlot. Overall, yeast supplements appear to possess the ability to improve animal health and metabolism while decreasing morbidity, thereby enhancing profitability of these animals. Full article
(This article belongs to the Special Issue Microbial Activity in Food)
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