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1.
Hig. aliment ; 38(298): e1144, jan.-jun. 2024.
Artigo em Português | LILACS, VETINDEX | ID: biblio-1531444

RESUMO

As falhas na higienização em um estabelecimento de alimentos podem refletir em problemas causando a contaminação ou deterioração do produto produzido. Esta pesquisa foi motivada por reclamações de consumidores informando que os queijos apresentaram fungos, mesmo estando dentro do prazo de validade e por solicitação do Serviço de Inspeção Municipal. O objetivo desta pesquisa foi avaliar a contaminação ambiental em uma agroindústria da agricultura familiar produtora de queijo colonial no Sudoeste Paranaense. Foram realizadas a contagem para aeróbios mesófilos em equipamentos e superfícies que entram em contato com o alimento e análise microbiológica ambiental de bolores e leveduras na sala de secagem dos queijos. A coleta foi realizada com método de esfregaço de suabe estéril para aeróbios mesófilos e semeadas em placas de Petri com Ágar Padrão de Contagem. Para a coleta ambiental foram expostas placas de Petri com ágar Saboraund durante 15 minutos. Os resultados demonstraram ausência de contaminação nas superfícies, mas foram encontrados bolores e leveduras de forma acentuada na sala de secagem dos queijos, o que pode contribuir para a deterioração do produto, diminuindo sua validade. Para minimizar as perdas por contaminação é necessário que o processo de higienização dos ambientes seja realizado de forma eficiente.


Failures in hygiene in a food establishment can result in problems causing contamination or deterioration of the product produced. This research was motivated by complaints from consumers reporting that the cheeses had mold, even though they were within their expiration date and at the request of the Municipal Inspection Service. This research was to evaluate environmental contamination in an agroindustry in the family farm producing colonial cheese in Southwest Paraná. For the microbiological assessment of environmental contamination, counting for mesophilic aerobes was carried out on equipment and surfaces that come into contact with food and, environmental microbiological analysis of molds and yeast in the cheese drying room. The collection was carried out using the sterile swab smear for mesophilic aerobes and seeded in Petri dishes with Counting Standard Agar. For environmental collection, sheets of Petri with Saboraund agar for 15 minutes. The results demonstrated absence of contamination on surfaces. But the presence of molds and yeasts in the drying room cheeses, which can contribute to the deterioration of the product and thus reduce the validity. To minimize losses due to contamination, it is It is necessary that the process of cleaning and disinfecting environments is carried out efficiently.


Assuntos
Higiene dos Alimentos , Queijo/microbiologia , Brasil , Boas Práticas de Fabricação , Doenças Transmitidas por Alimentos/prevenção & controle
2.
Compr Rev Food Sci Food Saf ; 23(1): e13262, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38284577

RESUMO

The growing emphasis on dietary health has facilitated the development of plant-based foods. Plant proteins have excellent functional attributes and health-enhancing effects and are also environmentally conscientious and animal-friendly protein sources on a global scale. The addition of plant proteins (including soy protein, pea protein, zein, nut protein, and gluten protein) to diverse cheese varieties and cheese analogs holds the promise of manufacturing symbiotic products that not only have reduced fat content but also exhibit improved protein diversity and overall quality. In this review, we summarized the utilization and importance of various plant proteins in the production of hybrid cheeses and cheese analogs. Meanwhile, classification and processing methods related to these cheese products were reviewed. Furthermore, the impact of different plant proteins on the microstructure, textural properties, physicochemical attributes, rheological behavior, functional aspects, microbiological aspects, and sensory characteristics of both hybrid cheeses and cheese analogs were discussed and compared. Our study explores the potential for the development of cheeses made from full/semi-plant protein ingredients with greater sustainability and health benefits. Additionally, it further emphasizes the substantial chances for scholars and developers to investigate the optimal processing methods and applications of plant proteins in cheeses, thereby improving the market penetration of plant protein hybrid cheeses and cheese analogs.


Assuntos
Queijo , Animais , Queijo/microbiologia , Proteínas de Plantas , Dieta
3.
Int J Food Microbiol ; 412: 110557, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38237418

RESUMO

Gouda cheeses of different production batches and ripening times often differ in metabolite composition, which may be due to the starter culture mixture applied or the growth of non-starter lactic acid bacteria (NSLAB) upon maturation. Therefore, a single Gouda cheese production batch was systematically investigated from the thermized milk to the mature cheeses, ripened for up to 100 weeks, to identify the main bacterial species and metabolites and their dynamics during the whole production and ripening. As this seemed to be starter culture strain- and NSLAB-dependent, it requested a detailed, longitudinal, and quantitative investigation. Hereto, microbial colony enumeration, high-throughput full-length 16S rRNA gene sequencing, and a metabolomic approach were combined. Culture-dependently, Lactococcus lactis was the most abundant species from its addition as part of the starter culture up to the first two months of cheese ripening. Afterward, the NSLAB Lacticaseibacillus paracasei became the main species during ripening. The milk was a possible inoculation source for the latter species, despite pasteurization. Culture-independently, the starter LAB Lactococcus cremoris and Lc. lactis were the most abundant species in the cheese core throughout the whole fermentation and ripening phases up to 100 weeks. The cheese rind from 40 until 100 weeks of ripening was characterized by a high relative abundance of the NSLAB Tetragenococcus halophilus and Loigolactobacillus rennini, which both came from the brine. These species were linked with the production of the biogenic amines cadaverine and putrescine. The most abundant volatile organic compound was acetoin, an indicator of citrate and lactose fermentation during the production day, whereas the concentrations of free amino acids were an indicator of the ripening time.


Assuntos
Queijo , Lactobacillales , Lactococcus lactis , Animais , Queijo/microbiologia , Leite/microbiologia , RNA Ribossômico 16S/análise , Lactobacillales/genética , Lactococcus lactis/genética
4.
Sci Rep ; 14(1): 2288, 2024 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-38280925

RESUMO

Bacterial cells can form biofilm on food contact surfaces, becoming a source of food contamination with profound health implications. The current study aimed to determine some Egyptian medicinal plants antibacterial and antibiofilm effects against foodborne bacterial strains in milk plants. Results indicated that four ethanolic plant extracts, Cinnamon (Cinnamomum verum), Chamomile (Matricaria chamomilla), Marigold (Calendula officinalis), and Sage (Salvia officinalis), had antibacterial (12.0-26.5 mm of inhibition zone diameter) and antibiofilm (10-99%) activities against Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes and Salmonella Typhimurium. The tested extracts had minimum inhibitory concentration values between 0.14 and 2.50 mg/ml and minimum bactericidal concentration values between 0.14 and 12.50 mg/ml. L. monocytogenes was more sensitive for all tested ethanolic extracts; Sage and Cinnamon showed a bacteriocidal effect, while Chamomile and Marigold were bacteriostatic. The ethanolic extracts mixture from Chamomile, Sage, and Cinnamon was chosen for its antibiofilm activity against L. monocytogenes using L-optimal mixture design. Gas chromatography and mass spectrometry analysis showed that this mixture contained 12 chemical compounds, where 2-Propenal,3-phenyl- had the maximum area % (34.82%). At concentrations up to 500 µg/ml, it had no cytotoxicity in the normal Vero cell line, and the IC50 value was 671.76 ± 9.03 µg/ml. Also, this mixture showed the most significant antibacterial effect against detached L. monocytogenes cells from formed biofilm in stainless steel milk tanks. At the same time, white soft cheese fortified with this mixture was significantly accepted overall for the panelist (92.2 ± 2.7) than other cheese samples, including the control group.


Assuntos
Queijo , Listeria monocytogenes , Animais , Aço Inoxidável/farmacologia , Queijo/microbiologia , Leite , Cromatografia Gasosa-Espectrometria de Massas , Biofilmes , Extratos Vegetais/farmacologia , Antibacterianos/farmacologia , Cinnamomum zeylanicum/química , Microbiologia de Alimentos
5.
Appl Environ Microbiol ; 90(2): e0165523, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38231565

RESUMO

Ten Gouda cheese wheels with an age of 31 weeks from six different batch productions were affected by a crack defect and displayed an unpleasant off-flavor. To unravel the causes of these defects, the concentrations of free amino acids, other organic acids, volatile organic compounds, and biogenic amines were quantified in zones around the cracks and in zones without cracks, and compared with those of similar Gouda cheeses without crack defect. The Gouda cheeses with cracks had a significantly different metabolome. The production of the non-proteinogenic amino acid γ-aminobutyric acid (GABA) could be unraveled as the key mechanism leading to crack formation, although the production of the biogenic amines cadaverine and putrescine contributed as well. High-throughput amplicon sequencing of the full-length 16S rRNA gene based on whole-community DNA revealed the presence of Loigolactobacillus rennini and Tetragenococcus halophilus as most abundant non-starter lactic acid bacteria in the zones with cracks. Shotgun metagenomic sequencing allowed to obtain a metagenome-assembled genome of both Loil. rennini and T. halophilus. However, only Loil. rennini contained genes necessary for the production of GABA, cadaverine, and putrescine. Metagenetics further revealed the brine and the rennet used during cheese manufacturing as the most plausible inoculation sources of both Loil. rennini and T. halophilus.IMPORTANCECrack defects in Gouda cheeses are still poorly understood, although they can lead to major economic losses in cheese companies. In this study, the bacterial cause of a crack defect in Gouda cheeses was identified, and the pathways involved in the crack formation were unraveled. Moreover, possible contamination sources were identified. The brine bath might be a major source of bacteria with the potential to deteriorate cheese quality, which suggests that cheese producers should regularly investigate the quality and microbial composition of their brines. This study illustrated how a multiphasic approach can understand and mitigate problems in a cheese company.


Assuntos
Carboxiliases , Queijo , Lactobacillales , Lactobacillus , Sais , Lactobacillales/genética , Queijo/microbiologia , RNA Ribossômico 16S/genética , Cadaverina , Putrescina , Bactérias/genética , Ácido gama-Aminobutírico , Ácido Láctico , Microbiologia de Alimentos
6.
Int J Food Microbiol ; 411: 110523, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38134579

RESUMO

Traditional products are particularly appreciated by consumers and among these products, cheese is a major contributor to the Italian mountainous area economics. In this study, shotgun metagenomics and volatilomics were used to understand the biotic and abiotic factors contributing to mountain Caciotta cheese typicity and diversity. Results showed that the origin of cheese played a significant role; however, curd cooking temperature, pH, salt concentration and water activity also had an impact. Viral communities exhibited higher biodiversity and discriminated cheese origins in terms of production farms. Among the most dominant bacteria, Streptococcus thermophilus showed higher intraspecific diversity and closer relationship to production farm when compared to Lactobacillus delbrueckii. However, despite a few cases in which the starter culture was phylogenetically separated from the most dominant strains sequenced in the cheese, starter cultures and dominant cheese strains clustered together suggesting substantial starter colonization in mountain Caciotta cheese. The Caciotta cheese volatilome contained prominent levels of alcohols and ketones, accompanied by lower proportions of terpenes. Volatile profile not only demonstrated a noticeable association with production farm but also significant differences in the relative abundances of enzymes connected to flavor development. Moreover, correlations of different non-homologous isofunctional enzymes highlighted specific contributions to the typical flavor of mountain Caciotta cheese. Overall, this study provides a deeper understanding of the factors shaping typical mountain Caciotta cheese, and the potential of metagenomics for characterizing and potentially authenticating food products.


Assuntos
Queijo , Lactobacillus delbrueckii , Animais , Queijo/microbiologia , Bactérias , Temperatura , Itália , Leite/microbiologia
7.
Int J Food Microbiol ; 411: 110548, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38154252

RESUMO

In this study, a comprehensive and comparative analysis was conducted on Italian Asiago-PDO cheese obtained from two different dairies named Dairy I and Dairy II using industrial and natural fermented milk, respectively. The analysis encompassed the evaluation of chemical composition, the succession of the microbiota during manufacture and ripening, and proteolysis mainly focusing on free individual amino acid (FAA) profiles. A metagenomic approach was used to investigate the cheese microbiome functionality. Differences in gross chemical composition were more evident during ripening, with Dairy II showing higher variability within batches. The microbiota varied significantly between the two dairies and ripening stages. The choice of starter culture shaped the microbiota during production and affected the microbial diversity of non-starter lactic acid bacteria (NSLAB) originated from the raw milk during ripening. Peptide chromatographic profiles and FAA concentrations increased as ripening progressed, with Dairy I showing higher production of FAA. Functional analysis of the metagenomes linked species to specific amino acid metabolism/catabolism pathways. The amino acid metabolism pathways, particularly those related to aromatic amino acids, lysine, and branched-chain amino acids, were affected by the presence of specific NSLAB species, which differed between the two dairies. The results obtained in this study reveal the impact of starter culture on peculiar cheese microbiota assemblies, which selectively targets amino acid pathways, providing insights into the potential flavor and aroma characteristics of Asiago-PDO cheese.


Assuntos
Queijo , Lactobacillales , Animais , Proteólise , Aminoácidos/metabolismo , Queijo/microbiologia , Lactobacillales/metabolismo , Leite/microbiologia
8.
Int J Food Microbiol ; 411: 110549, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38157636

RESUMO

Bouhezza is a traditional Algerian cheese produced and ripened in goatskin bags called Djeld. The aim of this study was to characterize the microbial ecosystem from Djeld (fresh and dried Djeld for making Bouhezza cheese) and the changes introduced by Lben microflora during its preparation and to identify its role in cheesemaking and its safety. Two replicates of fresh and dried skin bags (FS and DS) were sampled and analyzed before and after contact with Lben. The microbiological results showed no pathogens. Skins observed before the addition of Lben were less populated 2.86 and 3.20 log CFU cm-2 than skins examined after the addition of Lben (approximately 6.0 log CFU cm-2), suggesting a potential role of Lben in releasing some microorganisms into the skin during its time in the Djeld. However, an increase in mesophilic lactic acid bacteria and yeasts was observed in Lben after different periods of interaction with the skin. PCR-TTGE revealed the predominance of lactic acid bacteria (Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Staphylococcus equorum subsp. linens, Lactococcus cremoris, Streptococcus thermophilus) and a few high-GC-content bacteria (Lacticaseibacillus paracasei, Brevibacterium casei). Transfer of several microbial species was observed between the goatskin bag biofilm and Lben during the overnight interaction. Bands corresponding to Lacticaseibacillus paracasei, Brevibacterium casei, and Lactobacillus delbrueckii subsp. lactis were detected in the fresh skin profile and in Lben after contact with the fresh skin. Lacticaseibacillus paracasei was found in dried skin and Lben after contact with dry skin. Lactobacillus helveticus and Enterococcus faecalis appeared in the Lben profile and persisted in Lben and the biofilm-covered dry skin after interaction. These results demonstrate an exchange of specific microbial populations between goatskin bag biofilm and Lben during the traditional preparation method, suggesting that the diversity of goatskin biofilm contributes to the microbial diversity of Lben used in the production of Bouhezza cheese.


Assuntos
Queijo , Lactobacillales , Animais , Ecossistema , Lactobacillus , Streptococcus thermophilus , Queijo/microbiologia , Contagem de Colônia Microbiana , Leite/microbiologia , Microbiologia de Alimentos
9.
J Microbiol Methods ; 217-218: 106884, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38158082

RESUMO

Fourier transform infrared spectroscopy (FTIR) is an alternative microbial identification technique due to its faster analysis times and lower cost compared to molecular methods. In this study, forty-three fungal strains isolated from different Turkish traditional mold-ripened cheeses representing nine different Penicillium species (P. roqueforti, P. corylophilum, P. before, P. crustosum, P. spinulosum, P. rubens, P. brevicompactum, P. paneum, and P. solitum) were analyzed by using FTIR HTS-XT (High Throughput Screening Extension) method in the 4000-400 cm-1 wavenumber range. The spectra of the isolates were evaluated, and the chemical structures corresponding to the fungus-specific spectral regions were determined as fatty acids (3600-2800 cm-1), amide I and amide II of proteins and peptides (1740-1500 cm-1), polysaccharides (1200-900 cm-1) and carbohydrates (900-600 cm-1). The isolates were grouped according to the hierarchical clustering analysis (HCA) by applying chemometrics combined with FTIR spectroscopy. Results showed that FTIR spectroscopy has a high capability for rapid determination of cheese fungi based on their FTIR spectra.


Assuntos
Queijo , Queijo/microbiologia , Fungos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise por Conglomerados , Amidas
10.
Anim Sci J ; 94(1): e13905, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38102883

RESUMO

Brevibacterium linens (B. linens) is a dairy microorganism used in the production of washed cheese. However, there has been little research on B. linens, especially regarding its effects in vivo. Herein, we report the morphological characteristics of B. linens, such as its two-phase growth and V- and Y-shaped bodies. We also report that oral administration of B. linens increased the diversity of the gut microbiota and promoted the growth of lactobacilli and short-chain fatty acid-producing bacteria, such as Lachnospiraceae and Muribaculaceae. These findings suggest that the ingestion of B. linens may have beneficial effects in humans and animals.


Assuntos
Queijo , Microbioma Gastrointestinal , Humanos , Animais , Camundongos , Queijo/microbiologia , Lactobacillus , Bactérias , Administração Oral
11.
Open Vet J ; 13(10): 1277-1282, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38027405

RESUMO

Background: Food safety is an important subject that the global cheese industry increases awareness of. This urges these economic sectors to elevate the level of research to minimize cheese contamination with pathogenic bacteria, such as Salmonella. Aim: Based on these merits, this study was conducted to genotype Salmonella spp. isolated from cheese samples of local stores in Al-Diwaniyah City, Iraq. Methods: The study used 41 samples of local fresh unsalted white cheese in a selective-growth-based isolation of Salmonella. These isolates were confirmed utilizing a slide-agglutination (SA) test and VITEK® 2 system (V2S). Then, the isolates were subjected to conventional PCR and sequencing techniques that both targeted the 16S rRNA gene. For subtyping, the Salmonella isolates were subjected to a random amplified polymorphic DNA (RAPD)-PCR method. Results: The results of both SA and V2S revealed the presence of 14 (34.2%) isolates of Salmonella spp. in the cheese samples. The PCR confirmed 6 (42.9%) of these isolates, which further were defined with close nucleotide similarity (98.03%) and (97.88%) to different world isolates, such as Salmonella enterica subsp. Arizonae and Salmonella enterica subsp. enterica serovar Typhi, respectively. The RAPD-PCR findings showed different fragments for all the tested isolates. Conclusion: The present study indicates that the samples of the local fresh unsalted white cheese contain different Salmonella genotypes, which could be originated from different contamination sources.


Assuntos
Queijo , Salmonella enterica , Animais , Técnica de Amplificação ao Acaso de DNA Polimórfico/veterinária , Genótipo , Queijo/microbiologia , RNA Ribossômico 16S , Iraque , Salmonella/genética
12.
Cell Mol Biol (Noisy-le-grand) ; 69(9): 75-83, 2023 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-37807331

RESUMO

 Zhazhi cheese is a unique farmhouse traditional fermented dairy of the Kurdistan Region in Iraq for its desired aroma and flavor. Undoubtedly, the lactic acid bacteria (LAB) are the critical factors in developing the aroma, flavor, and texture of Zhazhi cheese but it has not been studied or characterised. LAB has many important nutritional benefits, including increasing the nutritional value of food. Therefore, this research was performed to isolate and identify the potential probiotic LAB from traditional homemade Kurdish cheese. Then, the identified strains were tested to determine their probiotics traits, which include acid resistance, bile-salt tolerance, haemolytic, DNase, hydrophobic, autoaggregation, antimicrobial and antibiotic activities. The isolated five LAB strains comprised Lactobacillus casei, Lactobacillus rhamnosus, Enterococcus faecium, Pediococcus pentocaseus and Lactobacillus helvaticum were recognized as promising and the most potential probiotics for further applications. This is the first report on the direct selection of potentially probiotic LAB from Kurdish special cheese (Zhazhi).


Assuntos
Queijo , Lactobacillales , Probióticos , Queijo/microbiologia , Iraque , Lactobacillus
13.
Int J Food Microbiol ; 406: 110401, 2023 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-37722266

RESUMO

Colour defects can affect the appearance of cheese, its flavour, the safety of its consumption, and the price it can demand. This work reports the identification of five fungal isolates from a dairy plant where the surface of most cheeses was affected by patent, reddish-to-brown stains. One of these isolates was obtained from cheese, two from brine, and two from a bulk tank containing ewe milk. Molecular identification by partial amplification, sequencing, and database comparison of the concatenated sequence of the genes coding for the largest subunit of RNA polymerase II (RPB2), ß-tubulin (ß-TUB), and the large subunit of the rRNA molecule (LSU), plus the internal transcribed sequence (ITS) regions, assigned the isolates to Epicoccum layuense, Epicoccum italicum, and Epicoccum mezzettii. Features of the growth of these different species on different agar-based media, and of the morphology of their conidia following sporulation, are also reported. The strain isolated from cheese, E. layuense IPLA 35011, was able to recreate the reddish-brown stains on slices of Gouda-like cheese, which linked the fungus with the colour defect. In addition, two other strains, E. italicum IPLA 35013 from brine and E. italicum IPLA 35014 from milk, also produced stains on cheese slices. Epicoccum species are widely recognized as plant pathogens but have seldom been reported in the dairy setting, and never as human or animal pathogens.


Assuntos
Queijo , Animais , Feminino , Ovinos , Humanos , Queijo/microbiologia , Leite/microbiologia , Sais , Paladar
14.
J Food Prot ; 86(12): 100158, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37699510

RESUMO

Fungal spoilage of food is a worldwide concern prompting the development of many antimicrobial agents and applications. In this study, the cell-free supernatant (CFS) of Lacticaseibacillus paracasei ALAC-4 had a significant inhibition effect on fungi. The CFS with antifungal activities were combined with chitosan (CS) matrix to prepare an active packaging CS-CFS films by using a solvent casting method and used for the packaging of Mongolian cheese for 15 days during storage at 4 ± 1℃. The optimized formulation of the film were 1.25% (w/v) chitosan, 1.75% (w/v) gelatin, 0.3% (v/v) glycerol, and 9.6% (w/v) CFS. It was found that CS-CFS films exhibited strong antifungal activities against molds and yeasts, especially Candida albicans, and also had excellent mechanical properties. Additionally, FTIR spectroscopy indicated that hydrogen bonds between the CFS and CS formed, and there was a smooth surface, compact cross-section observed in SEM morphologies of CS-CFS films. Furthermore, CS-CFS film also displayed a strong antifungal effect against molds and yeasts on cheese surface. These results suggest that the chitosan-based CS-CFS film has a promising application for Mongolian cheese and food preservation.


Assuntos
Queijo , Quitosana , Antifúngicos/farmacologia , Embalagem de Alimentos/métodos , Quitosana/farmacologia , Lacticaseibacillus , Queijo/microbiologia , Candida albicans
15.
Food Microbiol ; 115: 104309, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37567615

RESUMO

Penicillium camemberti is a domesticated species adapted to the dairy environment, which is used as adjunct cultures to ripen soft cheeses. A recent population genomics analysis on P. camemberti revealed that P. camemberti is a clonal lineage with two varieties almost identical genetically but with contrasting phenotypes in terms of growth, color, mycotoxin production and inhibition of contaminants. P. camemberti variety camemberti is found on Camembert and Brie cheeses, and P. camemberti variety caseifulvum is mainly found on other cheeses like Saint-Marcellin and Rigotte de Condrieu. This study aimed to evaluate the impact of water activity (aw) reduced by sodium chloride (NaCl) and the increase of carbon dioxide (CO2) partial pressure, on conidial germination and growth of two varieties of P. camemberti: var. Camemberti and var. Caseifulvum. Mathematical models were used to describe the responses of P. camemberti strains to both abiotic factors. The results showed that these genetically distant strains had similar responses to increase in NaCl and CO2 partial pressure. The estimated cardinal values were very close between the strains although all estimated cardinal values were significantly different (Likelihood ratio tests, pvalue = 0.05%). These results suggest that intraspecific variability could be more exacerbated during fungal growth compared with conidial germination, especially in terms of macroscopic morphology. Indeed, var. Caseifulvum seemed to be more sensitive to an increase of CO2 partial pressure, as shown by the fungal morphology, with the occurrence of irregular outgrowths, while the morphology of var. Camemberti remains circular. These data could make it possible to improve the control of fungal development as a function of salt and carbon dioxide partial pressure. These abiotic factors could serve as technological barriers to prevent spoilage and increase the shelf life of cheeses. The present data will allow more precise predictions of fungal proliferation as a function of salt and carbon dioxide partial pressure, which are significant technological hurdles in cheese production.


Assuntos
Queijo , Penicillium , Cloreto de Sódio/farmacologia , Esporos Fúngicos , Dióxido de Carbono , Queijo/microbiologia
16.
Food Microbiol ; 115: 104319, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37567629

RESUMO

Wooden vats are used in the production of some traditional cheeses as the biofilms on wooden vat surfaces are known to transfer large quantities of microbes to cheese. Variability in microbial communities on wooden vats could lead to inconsistent cheese production. In the present study, the influences of environmental conditions and milk type (raw or heat-treated) on the microbial composition of vat biofilms and cheeses made in the vats were studied using amplicon sequencing of bacterial 16S rRNA and fungal internal transcribed spacer genes. Results showed that the microbial composition of biofilms was influenced by environmental conditions but not the milk type used in cheese production. The microbial composition of cheeses can be further affected by bacterial contributions from milk and the selective forces of environmental conditions. Results of this study suggest that controlling environmental conditions could maintain a more consistent microbial composition of biofilms on wooden vats and resulting cheeses. The use of wooden vats coupled with heat-treated milk at one or more stages of cheese production might be a viable approach to produce cheese with high microbial diversities and reduce risks of undesirable microbes related to food safety and quality.


Assuntos
Queijo , Microbiota , Animais , Leite/microbiologia , Queijo/microbiologia , RNA Ribossômico 16S/genética , Bactérias/genética , Microbiota/genética , Microbiologia de Alimentos
17.
Braz J Microbiol ; 54(3): 2137-2152, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37450104

RESUMO

The biosafety of four potentially probiotic lactobacilli strains, isolated from artisanal Mexican Cocido cheese, was assessed through in vitro tests aimed to determine (1) the antibiotic susceptibility profile by broth microdilution, (2) the transferability of antibiotic resistance determinants by filter-mating, and (3) the phenotypic and genotypic stability during serial batch sub-culture (100-day period) by evaluating physiological and probiotic features and RAPD-PCR fingerprinting. Lactobacilli strains exhibited multidrug-resistance; however, resistance determinants were not transferred in the filter-mating assay. Significant (p < 0.05) differences were observed in bacterial morphology and some functional and technological properties when strains were serially sub-cultured over 50 generations (G50), compared to the initial cultures (G0). Conversely, the strains did not show mucinolytic and hemolytic activities either at G0 or after 100 generations (G100). Genetic polymorphism and genomic template instability on selected strains were detected, which suggest possible evolutionary arrangements that may occur when these bacteria are largely cultured. Our findings suggest that the assessed strains did not raise in vitro biosafety concerns; however, complementary studies are still needed to establish the safe potential applications in humans and animals.


Assuntos
Queijo , Probióticos , Humanos , Animais , Queijo/microbiologia , Lactobacillus/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Contenção de Riscos Biológicos , Técnicas In Vitro
18.
Int J Biol Macromol ; 246: 125685, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37406906

RESUMO

In this study, gliadin-carboxymethyl chitosan composite nanoparticles (GC NPs) co-encapsulated natamycin (Nata) and theaflavins (TFs) were constructed and added as an antioxidant, antifungal, and structural enhancer to carboxymethyl chitosan (CMCS) films. The stabilized GC NPs with a particle size of 160.7 ± 2.8 nm, a zeta potential of -29.0 ± 0.9 mV, and a protein content in the supernatant of 96 ± 1 % could be fabricated. Tests of pH and salt ions showed that the stability of NPs dispersion was based on electrostatic repulsion. Co-encapsulation of TFs enhanced the photostability of Nata and the antioxidant activity of the NPs dispersion. The interactions between gliadin with Nata and TFs were studied by molecular simulations. As a functional additive, the addition of Nata/TFs-GC NPs could improve the optical properties, mechanical properties, water-blocking capability, and antifungal and antioxidant activities of the CMCS films. The in-vivo test showed that the functional film could be used to inhibit the growth of Aspergillus niger on cheese.


Assuntos
Queijo , Quitosana , Nanopartículas , Natamicina/farmacologia , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Gliadina , Quitosana/química , Queijo/microbiologia , Nanopartículas/química , Embalagem de Alimentos
19.
Lett Appl Microbiol ; 76(7)2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37401169

RESUMO

The aim of this study was to investigate the effectiveness of essential oils (EOs) or crude extracts (CEs) of eight aromatic and medicinal plants (AMPs) and its association with enterocin OS1 on Listeria monocytogenes and food spoilage bacteria in Moroccan fresh cheese. The cheese batches were treated with EO of Rosmarinus officinalis, Thymus vulgaris, Syzygium aromaticum, Laurus nobilis, Allium sativum, Eucalyptus globulus, or CE of Crocus sativus and Carthamus tinctorius, and/or enterocin OS1, and stored for 15 days at 8°C. The data were subjected to correlations analysis, variance analysis, and principal components analysis. Results clearly showed a positive correlation between L. monocytogenes reduction and storage time. Moreover, reduction on Listeria counts induced by Allium-EO and Eucalyptus-EO reached 2.68 and 1.93 Log CFU/g with respect to untreated samples after 15 days, respectively. Similarly, enterocin OS1 alone has significantly reduced the L. monocytogenes population with 1.46 Log CFU/g. The most promising result was the synergy observed between many AMPs and enterocin. Indeed, treatments with Eucalyptus-EO + OS1 and Crocus-CE + OS1 decreased the Listeria population to undetectable after only 2 days and throughout the storage period. These findings suggest a promising application/use of this natural combination, which preserves the safety and long-lasting conservation of fresh cheese.


Assuntos
Queijo , Listeria monocytogenes , Plantas Medicinais , Microbiologia de Alimentos , Queijo/microbiologia , Contagem de Colônia Microbiana
20.
J Food Prot ; 86(9): 100128, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37442229

RESUMO

The presence of Shiga toxin-producing Escherichia coli (STEC) in dairy products made with raw milk is a major concern for food safety authorities and industries. Two approaches have been proposed to isolate STEC from food. In the IC-Protocol (immuno-concentration protocol), specific serogroups are identified in the enrichment broth after the detection of the stx and eae genes. An immuno-concentration of the targeted serogroups is performed before isolating them on specific media. In the DI-Protocol (direct isolation protocol), a direct isolation of all STEC present in the enrichment broth is carried out after the detection of stx genes. We compared the ability of these two methods to isolate STEC O26:H11, O103:H2, O111:H8, O145:H28, and O157:H7 after artificial inoculation in four different raw milk cheeses. Across all serogroups and cheese types, STEC were isolated in 83.3% of samples when using the IC-Protocol but only 53.3% of samples with the DI-Protocol. For two cheese types, the DI-Protocol failed to isolate STEC O157:H7 strains altogether. Our results suggest that IC-Protocol is a robust methodology to effectively isolate STEC across a range of cheese types.


Assuntos
Queijo , Microbiologia de Alimentos , Leite , Escherichia coli Shiga Toxigênica , Escherichia coli Shiga Toxigênica/classificação , Escherichia coli Shiga Toxigênica/genética , Escherichia coli Shiga Toxigênica/isolamento & purificação , Humanos , Leite/microbiologia , Queijo/microbiologia , Sorotipagem , Reações Falso-Negativas
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