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1.
Int J Food Microbiol ; 329: 108690, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32497790

RESUMO

Pecorino di Farindola is a typical cheese produced in the area surrounding the village of Farindola, located in the Abruzzo Region (central Italy), unique among Italian cheese because only raw ewe milk and pig rennet are used for its production. In the literature it is well documented that raw milk is able to support the growth of pathogenic microorganisms such as Listeria monocytogenes. Predictive microbiology can be useful in order to predict growth-death kinetics of pathogenic bacteria, on the basis of known environmental conditions. Aim of this study was to compare predictions obtained from a model, originally designed to predict the kinetics of L. monocytogenes in the dynamic growth-death environment of drying fresh sausage, with the results of challenge tests performed during the ripening of Pecorino di Farindola produced from artificially contaminated raw ewe milk. A challenge test was carried out using ewe raw milk inoculated with L. monocytogenes, in order to produce Pecorino di Farindola cheese stored at 18 °C for 149 days of ripening. During the ripening period, pH and aw values decreased in all samples analysed; lactic acid bacteria become the prevailing microbial population, while for L. monocytogenes a period of stability (neither growth nor death) followed the initial situation. The growth inhibition and the following inactivation may mostly be due to competition with the autochthonous microbiota and to the reduction of water activity. Mathematical modelling was used in order to predict microbial kinetics in the dynamic ripening environment, joining growth and death patterns in a continuous way, and including the highly uncertain growth/no growth range separating the two regions. The effect of lactic acid bacteria on the growth of pathogens was also included. Predicted microbial kinetics were satisfactory, as confirmed by the absence of statistically significant difference between observed and predicted values (p > 0.05). The present study proved, via challenge tests, that a dynamic growth/death model, previously used for a meat product, can be fruitfully used in cheese characterized by active competitive microbiota and progressive drying during ripening.


Assuntos
Queijo/microbiologia , Microbiologia de Alimentos , Listeria monocytogenes/crescimento & desenvolvimento , Modelos Biológicos , Animais , Itália , Cinética , Lactobacillales , Leite/microbiologia , Alimentos Crus/microbiologia
2.
Nat Commun ; 11(1): 2610, 2020 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-32451391

RESUMO

Lactic acid bacteria (LAB) are fundamental in the production of fermented foods and several strains are regarded as probiotics. Large quantities of live LAB are consumed within fermented foods, but it is not yet known to what extent the LAB we ingest become members of the gut microbiome. By analysis of 9445 metagenomes from human samples, we demonstrate that the prevalence and abundance of LAB species in stool samples is generally low and linked to age, lifestyle, and geography, with Streptococcus thermophilus and Lactococcus lactis being most prevalent. Moreover, we identify genome-based differences between food and gut microbes by considering 666 metagenome-assembled genomes (MAGs) newly reconstructed from fermented food microbiomes along with 154,723 human MAGs and 193,078 reference genomes. Our large-scale genome-wide analysis demonstrates that closely related LAB strains occur in both food and gut environments and provides unprecedented evidence that fermented foods can be indeed regarded as a possible source of LAB for the gut microbiome.


Assuntos
Microbiologia de Alimentos , Microbioma Gastrointestinal/genética , Lactobacillales/genética , Lactobacillales/isolamento & purificação , Animais , Bases de Dados Genéticas , Alimentos e Bebidas Fermentados/microbiologia , Humanos , Lactococcus lactis/genética , Lactococcus lactis/isolamento & purificação , Estilo de Vida , Metagenoma , Primatas/microbiologia , Probióticos , Streptococcus thermophilus/genética , Streptococcus thermophilus/isolamento & purificação
3.
PLoS One ; 15(5): e0233047, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32392269

RESUMO

Fruits have been widely considered as the default "health foods" because they contain numerous vitamins and minerals needed to sustain human health. Fermentation strategies have been utilized to enhance the nutritive and flavor features of healthy and readily consumable fruit products while extending their shelf lives. A traditional fermented multi-fruit beverage was made from five fruits including kiwi, guava, papaya, pineapple, and grape fermented by Saccharomyces cerevisiae along with lactic acid bacteria and acetic acid bacteria. The immunomodulatory properties of the fermented multi-fruit beverage, in vivo nonspecific and ovalbumin (OVA)-specific immune response experiments using female BALB/c mice were performed. Administration of the fermented multi-fruit beverage reduced the calorie intake, thus resulting in a less weight gain in mice compared to the water (placebo)-fed mice. In the nonspecific immune study model, the fermented multi-fruit beverage enhanced phagocytosis and T cell proliferation but did not affect B cell proliferation and immunoglobulin G (IgG) production. Analysis of cytokine secretion profile also revealed that the fermented multi-fruit beverage enhanced proinflammatory cytokines interleukin (IL)-6, tumor necrosis factor (TNF)-α, and T helper (Th)1-related cytokine interferon (IFN)-γ production, thus creating an immunostimulatory effect. Nonetheless, in the specific immune study model, the results showed that the fermented multi-fruit beverage decreased the production of proinflammatory cytokines IL-6 and TNF-α production in OVA-immunized mice. Moreover, it also caused a decrease in the production of anti-OVA IgG1, which was accompanied by a decrease in Th2-related cytokines IL-4 and IL-5 production and an increase in Th1-related cytokine IFN-γ production, indicating that it may have the potential to shift the immune system from the allergen-specific Th2 responses toward Th1-type responses. The results indicate that fermented multi-fruit beverage has the potential to modulate immune responses both in a nonspecific and specific manners.


Assuntos
Citocinas/metabolismo , Alimentos e Bebidas Fermentados/microbiologia , Frutas/imunologia , Ovalbumina/administração & dosagem , Linfócitos T/metabolismo , Acetobacteraceae/fisiologia , Administração Oral , Animais , Peso Corporal , Feminino , Imunoglobulina G/metabolismo , Lactobacillales/fisiologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Ovalbumina/imunologia , Fagocitose , Saccharomyces cerevisiae/fisiologia , Células Th1/imunologia , Células Th2/imunologia , Vacinação
4.
Arch Razi Inst ; 75(1): 63-73, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32292004

RESUMO

There is a growing concern regarding the recurrent observation of aflatoxins (AFs) in the milk of lactating animals. Regarding this, the present study was conducted to assess the aflatoxin M1 (AFM1)-binding ability of three species, namely Lactobacillus rhamnosus, L. plantarum, and Saccharomyces boulardii, inAFM1-contaminatedmilk. The mentioned species were administeredatthe concentrations of107 and 109 CFU/mLto skimmed milk contaminated with 0.5 and 0.75 ng/mL AFM1 within the incubation times of 30 and 90 min at 4°C and 37°C. Lactobacillus rhamnosus was found to have the best binding ability at the concentrations of 107 and 109 (CFU/ml), rendering 82% and 90% removal in the milk samples with 0.5 and 0.75 ng/ml AFM1, respectively. Accordingly, this value at 107 and 109 CFU/ml of L. plantarum was obtained 89% and 82% with 0.75 ng/ml of AFM1, respectively. For S. boulardii at 107 and 109 CFU/ml, the rates were respectively estimated at 75% and 90% with 0.75 ng/ml of AFM1. The best AFM1-binding levels for L. rhamnosus, L. plantarum, and S. boulardii were 91.82±10.9%, 89.33±0.58%, and 93.20±10.9, respectively, at the concentrations of 1×109, 1×107, and 1×107 CFU/ml at 37, 4, and 37°C, respectively. In this study, the maximum AFM1 binding (100.0±0.58) occurred while a combination of the aforementioned probiotics was employed at a concentration of 1×107 CFU/ml at 37°C with 0.5 ng/ml AFM1, followed by the combination of L. rhamnosus and L. plantarum (95.86±10.9) at a concentration of 1×109 CFU/ml at the same temperature with 0.75 ng/ml AFM1. It was concluded that the use of S. boulardii in combination with Lactobacillus rhamnosus and L. plantarum, which bind AFM1 in milk, can decrease the risk of AFM1 in dairy products.


Assuntos
Aflatoxina M1/metabolismo , Contaminação de Alimentos/prevenção & controle , Lactobacillales/metabolismo , Leite/química , Saccharomyces boulardii/metabolismo , Animais , Biodegradação Ambiental
5.
Int J Mol Sci ; 21(7)2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32276519

RESUMO

Lactic acid bacteria can act as reservoirs of antibiotic resistance genes that can be ultimately transferred to pathogens. The present work reports on the minimum inhibitory concentration (MIC) of 16 antibiotics to 25 LAB isolates of five Lactobacillus and one Bifidobacterium species from the human vagina. Acquired resistances were detected to kanamycin, streptomycin, chloramphenicol, gentamicin, and ampicillin. A PCR analysis of lactobacilli failed to identify genetic determinants involved in any of these resistances. Surprisingly, a tet(W) gene was detected by PCR in two Bifidobacterium bifidum strains, although they proved to be tetracycline-susceptible. In agreement with the PCR results, no acquired genes were identified in the genome of any of the Lactobacillus spp. strains sequenced. A genome analysis of B. bifidum VA07-1AN showed an insertion of two guanines in the middle of tet(W) interrupting the open reading frame. By growing the strain in the presence of tetracycline, stable tetracycline-resistant variants were obtained. An amino acid substitution in the ribosomal protein S12 (K43R) was further identified as the most likely cause of VA07-1AN being streptomycin resistance. The results of this work expand our knowledge of the resistance profiles of vaginal LAB and provide evidence for the genetic basis of some acquired resistances.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Lactobacillales/fisiologia , Polimorfismo Genético , Vagina/microbiologia , Bifidobacterium bifidum/efeitos dos fármacos , Bifidobacterium bifidum/genética , Bifidobacterium bifidum/fisiologia , Feminino , Humanos , Lactobacillales/efeitos dos fármacos , Lactobacillales/genética , Lactobacillus/efeitos dos fármacos , Lactobacillus/genética , Lactobacillus/fisiologia , Tetraciclina/farmacologia
6.
J Biosci Bioeng ; 130(1): 63-70, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32265130

RESUMO

Japanese sake production involves three processes: rice koji fermentation, seed mash fermentation, and main mash fermentation. Traditional seed mash (kimoto) production utilizes natural lactic acid produced by lactic acid bacteria for pure cultures of only sake yeast, preventing the growth of wild yeast and other unwanted bacteria. Recently, because kimoto production requires substantial time and labor, sake yeast mass-cultured in usual liquid medium has been used as a seed mash alternative. Sake quality is highly similar to that of kimoto, suggesting that they share similar component profiles. However, comparative component analyses of sake brewed with kimoto and sake brewed with cultured yeast are lacking. In this study, a time-course analysis of hydrophilic compounds in the main mash brewed with kimoto and with cultured yeast as well as a sensory evaluation of the products were performed. As a result, differences in various compounds and in umami taste level between sake brewed with kimoto and cultured yeast were detected. This is the first comparative analysis of changes in the component profile during sake main mash brewing using kimoto seed mash and cultured sake yeast; our results clarify the effects of kimoto seed mash on main mash brewing and sake quality.


Assuntos
Bebidas Alcoólicas/análise , Aromatizantes/química , Leveduras/metabolismo , Bebidas Alcoólicas/microbiologia , Fermentação , Aromatizantes/metabolismo , Humanos , Ácido Láctico/análise , Ácido Láctico/metabolismo , Lactobacillales/metabolismo , Oryza/química , Oryza/metabolismo , Oryza/microbiologia , Sementes/química , Sementes/metabolismo , Sementes/microbiologia , Paladar
7.
J Dairy Sci ; 103(5): 4013-4025, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32113772

RESUMO

Breast milk is the main source of nutrition for infants; it contains considerable microflora that can be transmitted to the infant endogenously or by breastfeeding, and it plays an important role in the maturation and development of the immune system. In this study, we isolated and identified lactic acid bacteria (LAB) from human colostrum, and screened 2 strains with probiotic potential. The LAB isolated from 40 human colostrum samples belonged to 5 genera: Lactobacillus, Bifidobacterium, Streptococcus, Enterococcus, and Staphylococcus. We also isolated Propionibacterium and Actinomyces. We identified a total of 197 strains of LAB derived from human colostrum based on their morphology and 16S rRNA sequence, among them 8 strains of Bifidobacterium and 10 strains of Lactobacillus, including 3 Bifidobacterium species and 4 Lactobacillus species. The physiological and biochemical characteristics of strains with good probiotic characteristics were evaluated. The tolerances of some of the Bifidobacterium and Lactobacillus strains to gastrointestinal fluid and bile salts were evaluated in vitro, using the probiotic strains Bifidobacterium lactis BB12 and Lactobacillus rhamnosus GG as controls. Among them, B. lactis Probio-M8 and L. rhamnosus Probio-M9 showed survival rates of 97.25 and 78.33% after digestion for 11 h in artificial gastrointestinal juice, and they exhibited growth delays of 0.95 and 1.87 h, respectively, in 0.3% bile salts. These two strains have the potential for application as probiotics and will facilitate functional studies of probiotics in breast milk and the development of human milk-derived probiotics.


Assuntos
Bifidobacterium/fisiologia , Colostro/microbiologia , Lactobacillales/fisiologia , Probióticos , Animais , Bifidobacterium/isolamento & purificação , Bifidobacterium animalis/isolamento & purificação , Enterococcus/isolamento & purificação , Feminino , Humanos , Lactobacillales/isolamento & purificação , Lactobacillus/isolamento & purificação , Gravidez , Probióticos/isolamento & purificação , RNA Ribossômico 16S
8.
J Dairy Sci ; 103(5): 4100-4108, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32197850

RESUMO

Staphylococcus aureus is one of the main causative agents of food poisoning. This bacterium is an important component of cheese microbiota and plays an important role in foodborne diseases. Another important component of the microbiota is the lactic acid bacterium, which actively participates in processes that define the physicochemical, sensorial, and microbiological features of cheese. Of the various microbiological interactions in cheese, the interaction between lactic acid bacteria and Staph. aureus is most relevant. To this end, we evaluated the viability of Staph. aureus strains and the expression of their enterotoxins in cheeses produced experimentally, using Weissella paramesenteroides GIR16L4 or Lactobacillus rhamnosus D1 or both as starter cultures. Over 7 d, we observed that the presence of lactic acid bacteria did not impair Staph. aureus growth. However, via qPCR we observed a change in the gene expression of staphylococcal enterotoxins, suggesting that molecular communication exists between Staph. aureus strains and lactic acid bacteria in cheese.


Assuntos
Toxinas Bacterianas/metabolismo , Queijo/microbiologia , Enterotoxinas/metabolismo , Lactobacillus rhamnosus/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Superantígenos/metabolismo , Weissella/crescimento & desenvolvimento , Animais , Toxinas Bacterianas/genética , Queijo/análise , Enterotoxinas/genética , Microbiologia de Alimentos , Lactobacillales/metabolismo , Lactobacillus rhamnosus/metabolismo , Leite , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Superantígenos/genética , Transcriptoma , Weissella/metabolismo
9.
Food Chem ; 318: 126521, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32151927

RESUMO

Isoflavones intake is associated with health benefits. The metabolism of isoflavones by bacteria plays a key role in their biotransformation. Therefore, commercial soy drink was fermented by 11 lactic acid bacteria (LAB) and 9 bifidobacteria strains. The majority of the strains showed deglycosylation of the isoflavone glycosides present in soy drink and appearance of the aglycones daidzein, genistein and glycitein. Moreover, we observed the further transformation of daidzein into O-desmethylangolensin (O-DMA) and tetrahydrodaidzein, alongside with dihydrodaidzein (DHD) and a putative isomer of DHD. On the other hand, genistein was transformed by nearly all strains into 6-hydroxy-O-desmethylangolensin (6-hydroxy-O-DMA), but no dihydrogenistein production was registered. A high concentration of 2-(4-hydroxyphenyl)-propionic acid was observed, suggesting the degradation of O-DMA and 6-hydroxy-O-DMA. The potential of LAB and Bifidobacterium strains to produce functional soy drink enriched with bioactive isoflavones is demonstrated in this work.


Assuntos
Bifidobacterium/metabolismo , Alimentos e Bebidas Fermentados/microbiologia , Isoflavonas/metabolismo , Lactobacillales/metabolismo , Leite de Soja/metabolismo , Genisteína/metabolismo , Humanos , Propionatos/metabolismo
10.
Int J Food Microbiol ; 323: 108586, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32199192

RESUMO

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS), a culture based alternative for microbial diversity studies, is an attractive tool to dereplicate large numbers of isolates to a smaller set of representatives for downstream characterization. In the present study, MALDI-TOF MS, combined with a database of reference spectra compiled in previous studies, was applied to identify 88 non-starter lactic acid bacteria (NSLAB) isolated from 18 samples of four different artisanal cheeses produced in the Island of Naxos, Greece, from raw sheep and goat milk without the addition of starters. Eighty-four isolates (95.5%) could be identified directly via MALDI-TOF MS. Lactobacillus brevis and Lactobacillus plantarum were the dominant species, followed by Lactococcus lactis, Leuconostoc mesenteroides Lactobacillus paracasei, Lactobacillus rhamnosus, Pediococcus pentosaceus and Enterococcus faecium. The remaining four isolates represented species present in the database; however, within-species diversity was insufficiently covered. Additionally, pheS sequencing was applied to confirm identification.


Assuntos
Queijo/microbiologia , Microbiologia de Alimentos/métodos , Lactobacillales/classificação , Lactobacillales/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Animais , Biodiversidade , Grécia , Lactobacillales/química , Leite/microbiologia , Ovinos
11.
J Appl Microbiol ; 129(1): 116-136, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32141152

RESUMO

Probiotics administration in aquafeed is known to increase feed consumption and absorption due to their capacity to release a wide range of digestive enzymes and nutrients which can participate in digestion process and feed utilization, along with the absorption of diet components led to an increase in host's health and well-being. Furthermore, probiotics improve gut maturation, prevention of intestinal disorders, predigestion of antinutrient factors found in the feed ingredients, gut microbiota, disease resistance against pathogens and metabolism. The beneficial immune effects of probiotics are well established in finfish. However, in comparison, similar studies are less abundant in the shellfish. In this review, the discussions will mainly focus on studies reported the last 2 years. In recent studies, native probiotic bacteria were isolated and fed back to their hosts. Although beneficial effects were demonstrated, some studies showed adverse effects when treated with a high concentration. This adverse effect may be due to the imbalance of the gut microbiota caused by the replenished commensal probiotics. Probiotics revealed greatest effect on the shrimp digestive system particularly in the larval and early post-larval stages, and stimulate the production of endogenous enzymes in shrimp and contribute with improved the enzyme activities in the gut, as well as disease resistance.


Assuntos
Aquicultura , Bacillus/fisiologia , Suplementos Nutricionais , Lactobacillales/fisiologia , Probióticos/administração & dosagem , Fenômenos Fisiológicos da Nutrição Animal , Animais , Peixes/imunologia , Peixes/microbiologia , Microbioma Gastrointestinal , Probióticos/efeitos adversos , Frutos do Mar/microbiologia
12.
Plant Foods Hum Nutr ; 75(2): 223-229, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32100163

RESUMO

Comparative study of four edible coatings of wheat bread containing lactic acid bacteria showed that coating with Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus acidophilus, sodium alginate, whey and glycerol had the best protective properties against microbial spoilage. The viability of lactic acid bacteria was high in the coating containing alginate and whey: a loss in viability was in one - three orders of magnitude lower from initial concentration of 108-109 CFU/g coating after 120 h of storage. Wheat bread with edible coating did not differ by organoleptic assessment from control. The application of edible coating containing lactic acid bacteria to wheat bread diminished the number of mesophilic aerobic and facultative aerobic bacteria in the bread crust and protected it from contamination of mycelium fungi of genera Aspergillus and Penicillium that could preserve wheat bread from mold spoilage and increase shell life.


Assuntos
Lactobacillales , Probióticos , Pão , Lactobacillus , Triticum
13.
Int J Food Microbiol ; 322: 108547, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32097827

RESUMO

The present study aimed to characterize lactic acid bacteria involved in the different processing steps of tchapalo, a traditional Ivoirian beverage, for their potential application as starter cultures in food and beverages. Lactic acid bacteria (LAB) were therefore isolated and enumerated at different steps of the process on MRS and BEA agars. Of the 465 isolates, 27 produced bacteriocins that inhibit Lactobacillus delbrueckii F/31 strain. Of those, two also inhibited Listeria innocua ATCC 33090, while two others displayed inhibitory activity against L.innocua ATCC 33090, E. faecalis CIP 105042, E. faecalis ATCC 29212, Streptococcus sp. clinical LNSP, E. faecalis CIP 105042 and E. faecium ATCC 51558. The dominant species involved in tchapalo LAB fermentation, as determined by 16S rRNA gene sequencing, were Lactobacillus fermentum (64%), followed by Pediococcus acidilactici (14%). Two strains representing the two dominant species, L. fermentum S6 and P. acidilactici S7, and two potential bacteriocin producers, Weissella confusa AB3E41 and Enterococcus faecium AT1E22, were selected for further characterization. First, genome analysis showed that these strains do not display potential harmful genes such as pathogenic factors or transmissible antibiotic resistance genes. Furthermore, phylogenetic analyses were performed to assess evidence of eventual links to groups of strains with particular properties. They revealed that (i) L. fermentum S6 and P. acidilactici S7 are closely related to strains that ferment plants, (ii) E. faecium AT1E22 belongs to the environmental clade B of E. faecium, while W. confusa is quite similar to other strains also isolated from plant fermentations. Further genome analysis showed that E. faecium AT1E22 contains the Enterocin P gene probably carried by a megaplasmid, whereas no evidence of a bacteriocin gene was found in W. confusa AB3E41. The metabolic and the first step of the probiotic potentials of the different strains were analyzed. Lactobacillus fermentum S6 and P. acidilactici S7 are good candidates to develop starter cultures, and E. faecium AT1E22 should be further tested to confirm its potential as a probiotic strain in the production of sorghum wort.


Assuntos
Cerveja/microbiologia , Lactobacillales/isolamento & purificação , Sorghum/microbiologia , Bacteriocinas/genética , Bacteriocinas/metabolismo , Fermentação , Genoma Bacteriano/genética , Lactobacillales/classificação , Lactobacillales/genética , Lactobacillales/metabolismo , Listeria/crescimento & desenvolvimento , Filogenia , Probióticos/classificação , Probióticos/metabolismo , RNA Ribossômico 16S/genética
14.
Int J Food Microbiol ; 322: 108545, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32109681

RESUMO

PVOH-based polymer matrices in the form of films were evaluated as carriers of living Lactococcus lactis subsp. Lactis. These lactic acid bacteria are capable of producing nisin, which is an effective antilisterial peptide. A low percentage (1:0.125 w/w) of yeast extract, gelatin, sodium caseinate, gelatin, or casein hydrolysates was incorporated in PVOH matrices with the aim of increasing the viability of bacteria in the film. The films were obtained by casting after incorporating L. lactis. Then they were evaluated for antilisterial activity in liquid medium at 37 °C for 24 h, and also at 4 °C for 21 days in order to simulate the storage of liquid foods in refrigeration conditions. The survival of the lactic acid bacteria was also evaluated at both temperatures during the experiment. L. lactis remained viable in all the films tested at 37 and 4 °C. The antimicrobial activity of the films was greater at 4 °C than at 37 °C. With regard to the effect of the film composition, the activity of the films was higher when protein hydrolysates and sodium caseinate were incorporated in the formulation. Films supplemented with protein hydrolysates or sodium caseinate inhibited growth of the pathogen during the 21 days of storage at 4 °C. At 37 °C, after 24 h the films had slowed the growth of the inoculated pathogen by between 2 and 4 log CFU/mL. Finally, as the films developed are intended to be used in the design of active packaging of foods, they were tested in pasteurized milk inoculated with 4 log CFU/mL of Listeria monocytogenes and stored at 4 °C for 21 days. The pathogen began to grow after the second day of storage with or without film, but when the films were added to the medium the growth of the pathogen was slowed down, without reaching >6 log CFU, whereas the control reached a maximum growth of 8.5 log CFU. The pH of the milk was monitored throughout the experiment, and it decreased with time. This was due to the generation of organic acids by the lactic bacteria. Buffering the food stabilized the pH without modifying the activity of the films. Thus, the current study shows that PVOH films supplemented with nutrients can act as carriers of L. lactis, and they can help to increase the safety of refrigerated dairy beverages and sauces.


Assuntos
Conservação de Alimentos/métodos , Lactobacillales/fisiologia , Listeria monocytogenes/crescimento & desenvolvimento , Leite/microbiologia , Álcool de Polivinil , Animais , Antibacterianos/metabolismo , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Conservantes de Alimentos/metabolismo , Lactobacillales/química , Lactobacillales/metabolismo , Lactococcus lactis/química , Lactococcus lactis/metabolismo , Lactococcus lactis/fisiologia , Nisina/metabolismo , Proteínas/química , Refrigeração
15.
J Anim Sci ; 98(2)2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32017844

RESUMO

Fermented concentrated feed has been widely recognized as an ideal feed in the animal industry. In this study, we used a powerful method, coupling propidium monoazide (PMA) pretreatment with single-molecule real-time (SMRT) sequencing technology to compare the bacterial and fungal composition of feeds before and after fermentation with four added lactic acid bacteria (LAB) inoculants (one Lactobacillus casei strain and three L. plantarum strains). Five feed samples consisting of corn, soybean meal, and wheat bran were fermented with LAB additives for 3 d. Following anaerobic fermentation, the pH rapidly decreased, and the mean numbers of LAB increased from 106 to 109 colony-forming units (cfu)/g fresh matter. SMRT sequencing results showed that the abundance and diversity of bacteria and fungi in the feed were significantly higher before fermentation than after fermentation. Fifteen bacterial species and eight fungal genera were significantly altered following fermentation, and L. plantarum was the dominant species (relative abundance 88.94%) in the post-fermentation group. PMA treatment revealed that the bacteria Bacillus cereus, B. circulans, Alkaliphilus oremlandii, Cronobacter sakazakii, Paenibacillus barcinonensis, and P. amylolyticus (relative abundance >1%) were viable in the raw feed. After fermentation, their relative abundances decreased sharply to <0.2%; however, viable L. plantarum was still the dominant species post fermentation. We inferred that our LAB additives grew rapidly and inhibited harmful microorganisms and further improved feed quality. In addition, coupling PMA treatment with the Pacific Biosciences SMRT sequencing technology was a powerful tool for providing accurate live microbiota profiling data in this study.


Assuntos
Bactérias/classificação , Fungos/classificação , Microbiota , Micobioma , Silagem/microbiologia , Animais , Azidas , Bactérias/genética , Reatores Biológicos , Fermentação , Fungos/genética , Lactobacillales , Propídio/análogos & derivados , Soja , Triticum , Zea mays
16.
J Food Sci ; 85(3): 556-566, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32067252

RESUMO

A novel dairy product, namely "chocolate cheese", was produced with two typical Sicilian food products: Pecorino cheese, processed from ewe's milk, and Modica chocolate. The cheese, manufactured with 0%, 5%, 10%, and 15% (w/w) solid or molten chocolate, was evaluated after 0, 2, 4, and 6 weeks of vacuum storage for its nutritional and health properties. The addition of chocolate reduced the pH, protein, fat, and ash; the addition of 5% or 10% molten chocolate reduced hardness (N/mm2 ). The addition of either solid or molten chocolate resulted in a slight increase (P < 0.1038) in the total polyphenol content, a higher oleic acid content, and less oxidative stability. The microbiological profile showed that the total mesophilic count and the number of mesophilic coccus lactic acid bacteria (LAB) were approximately equal (about 108 CFU/g) in all cheese. The survival of the microorganisms was affected by both the chocolate added and the storage time. Chocolate cheese stored for 6 weeks had less Enterobacteriaceae than control cheese, whereas yeasts were detected at higher cell densities in the former cheese. Filamentous fungi were undetectable in some cheese. Differences were also observed in the number of mesophilic rod LAB, which increased progressively over time in all cheese, and in Enterobacteriaceae, yeasts, and filamentous fungi, which decreased during storage. Descriptive and hedonic sensory tests and principal component analysis showed that fresh cheese and cheese stored for 2 weeks, including 5% molten chocolate, were the most preferred by evaluators. Based on these results, chocolate cheese has the potential to be appreciated in the market for its nutritional, health, and sensory properties. PRACTICAL APPLICATION: Chocolate cheese, made by combining two typical Sicilian foods, Pecorino cheese and Modica chocolate, is proposed as a novel dairy product. The highest sensory acceptance was obtained with the addition of 5% molten chocolate and storage for 2 weeks. Given its improved antioxidant properties, healthier fat, and sensory properties, chocolate cheese has the potential to be appreciated in the market, especially by young consumers.


Assuntos
Antioxidantes/análise , Queijo/análise , Chocolate/análise , Aditivos Alimentares/análise , Leite/química , Animais , Cacau/química , Feminino , Humanos , Lactobacillales/crescimento & desenvolvimento , Leite/microbiologia , Ovinos , Paladar
17.
J Dairy Sci ; 103(4): 3025-3037, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32008781

RESUMO

Poro de Tabasco cheese (PTC) is one of the most popular cheeses in southern Mexico. It has been made by traditional, nonstandardized artisanal techniques dating back more than 50 yr. These techniques result in the cheese having a heterogeneous chemical and microbiological composition and, consequently, distinct organoleptic characteristics. Scientific interest in artisanal cheese is growing because it represents a source of bacteria with potential health benefits. However, the quality of raw-milk cheeses often does not comply with official sanitary standards. The objective of the present study was to explore the chemical composition and microbiological quality of PTC and to describe its production process. Based on chemical composition, this cheese can be classified as a hard, full-fat, fresh cheese, with moisture on a fat-free basis and fat in dry matter ranging from 41 to 55% and from 49 to 57%, respectively. The chemical and microbiological composition of PTC varied among the evaluated dairies due to the lack of standardization in the production process. Microbial populations decreased during production, which may be associated with high acidity and high salt and low moisture contents, the presence of lactic acid bacteria or antimicrobial substances, and the drainage of whey. However, despite the absence of Escherichia coli, Salmonella spp., and Listeria monocytogenes in final cheeses for all dairies, Staphylococcus aureus and its toxins were found in some samples from one dairy. Therefore, heat treatment for milk and good manufacturing practices should be implemented throughout the entire production process to ensure a safe product.


Assuntos
Queijo , Microbiologia de Alimentos , Animais , Bovinos , Queijo/análise , Manipulação de Alimentos , Lactobacillales , Listeria monocytogenes , México , Leite/microbiologia , Salmonella , Staphylococcus aureus
18.
J Dairy Sci ; 103(4): 2969-2981, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32059859

RESUMO

Enterococcus hirae WEHI01 is a potential probiotic strain isolated from a healthy Chinese infant. This strain has previously been characterized as having cholesterol-lowering potential and good dairy fermentation performance. In this study, we used rat models with obesity and type 2 diabetes mellitus (T2DM) induced by a high fat and sucrose diet and low-dose streptozotocin, respectively, and we evaluated the effect of E. hirae WEHI01 on glycolipid metabolism, glycolipid-related gene expression, organ histopathology, and intestinal flora changes in the 2 models. Our results showed that administration of 5.0 × 109 cfu of E. hirae WEHI01 for 4 wk decreased serum lipid levels and regulated glycolipid metabolism in the liver of obese rats. Following continuous administration of the same concentration of E. hirae WEHI01 to a T2DM rat model for another 5 wk, E. hirae WEHI01 improved glucose tolerance, recovered body weight loss, and led to significant decreases in tumor necrosis factor-α, IL-6, IL-10, and total bile acid in serum. We also found that E. hirae WEHI01 restored the morphology of the pancreas, kidney, and liver, and changed the composition of the gut microbiota (i.e., decreased the Shannon index, increased the Simpson index, and substantially increased the abundance of Lactobacillales). Combining the results for the obese model and the T2DM model, we speculated that beneficial effects of E. hirae WEHI01 on T2DM could be due to (1) a significant increase in PPARA expression and a tendency for increased CYP7A1 expression in the liver of obese rats, promoting the conversion of cholesterol into bile acid and reducing serum total bile acid levels in T2DM model rats; or (2) a change in gut microbial diversity, especially elevated Lactobacillales abundance, which reduced the total bile acid in T2DM model rats. These results demonstrated that E. hirae WEHI01 has the potential to ameliorate type 2 diabetes in rats and provide a promising rationale for further research into the prevention and treatment of T2DM.


Assuntos
Diabetes Mellitus Tipo 2/terapia , Streptococcus faecium ATCC 9790/isolamento & purificação , Microbioma Gastrointestinal , Lactobacillales , Animais , Grupo com Ancestrais do Continente Asiático , Ácidos e Sais Biliares/sangue , Metabolismo dos Carboidratos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Lactente , Metabolismo dos Lipídeos , Fígado/metabolismo , Masculino , Obesidade/complicações , Ratos , Ratos Sprague-Dawley
19.
Int J Food Microbiol ; 321: 108561, 2020 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-32078868

RESUMO

Lyophilized postbiotics of Lactobacillus plantarum was prepared and impregnated in bacterial nanocellulose (BNC) by ex-situ method to develop an antimicrobial ground meat wrapping nanopaper. The postbiotics incorporated BNC (P-BNC) films were optimized by response surface methodology and their antimicrobial activity against Listeria monocytogenes were examined. The BNC with postbiotics at 21.21% concentration and 28 min impregnation time was chosen as an optimized P-BNC film. The FTIR results confirmed the immobilization of postbiotics in BNC. The P-BNC film represented a significant reduction (~5 log cycles) in L.monocytogenes counts in ground meat at the end of the storage period (9 days at 4 °C). Meat wrapped by P-BNC film displayed a significant decrease in total mesophilic and psychrophiles count and TBA values than the controls. BNC can be considered as a proper carrier for development of antimicrobial film using postbiotics of LAB for food application.


Assuntos
Anti-Infecciosos/química , Celulose/química , Embalagem de Alimentos/métodos , Lactobacillales/química , Produtos da Carne/microbiologia , Animais , Anti-Infecciosos/farmacologia , Microbiologia de Alimentos , Armazenamento de Alimentos , Liofilização , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Produtos da Carne/análise
20.
Int J Food Microbiol ; 321: 108546, 2020 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-32087410

RESUMO

The demand for sugar reduction in products across the food and beverage industries has evoked the development of novel processes including the application of fermentation with lactic acid bacteria. Heterofermentative lactic acid bacteria (LAB) are diverse in their ability to utilise fermentable sugars and can also convert fructose into the sweet tasting polyol, mannitol. The sourdough microbiota has long been recognised as an ecological niche for a range of homofermentative and heterofermentative lactic acid bacteria. A leading determinant in the biodiversity of sourdough microbial populations is the type of flour used. Ten non-wheat flours were used and back-slopped for 7 days resulting in the isolation of 52 mannitol producing isolates which spanned six heterofermentative species of the genera Lactobacillus, Leuconostoc and Weissella. Assessment of mannitol productivity in fructose concentrations up to 100 g/L found Leuconostoc citreum TR116, to have the best mannitol producing characteristics, consuming 95% of available fructose and yielding 0.68 g of mannitol per gram of fructose consumed which equates to the maximal theoretical yield. Investigation of the effects of initial pH on mannitol production and other fermentation parameters in the isolates found pH 7 to be best for isolates Lactobacillus brevis TR052, Leuconostoc fallax TR111, Leuconostoc citreum TR116, Leuconostoc mesenteroides TR154 and Weissella paramesenteroides TR212, while pH 6 was optimal for Leuconostoc pseudomesenteroides TR080. The fermentation of apple juice with each isolate resulted in sugar reduction ranging from 30.3-74.0 g/L (34-72%). When apple juice fermentation with Leuconostoc citreum TR116 was scaled up to 1 L bioreactor a reduction in sugar of 98.6 g/L (83%) was achieved along with the production of 61.6 g/L mannitol. This demonstrates a fermentative process for sugar reduction in fruit juice with concomitant production of the sweet metabolite mannitol to create a fermentate that is suitable for further development as a low sugar fruit juice alternative.


Assuntos
Lactobacillales/isolamento & purificação , Lactobacillales/metabolismo , Manitol/metabolismo , Açúcares/metabolismo , Biodiversidade , Reatores Biológicos/microbiologia , Pão/microbiologia , Fermentação , Microbiologia de Alimentos , Frutose/metabolismo , Concentração de Íons de Hidrogênio , Lactobacillales/classificação
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