Potencial probiótico in vitro de bactérias ácido-láticas isoladas de queijo-de-minas artesanal da Serra da Canastra, MG

Artisanal Brazilian Cheeses-History, Marketing, Technological and Microbiological Aspects

This review focused on the historical, marketing, technological, and microbiological characteristics of artisanal Brazilian cheese. Brazilian cheese production was introduced and developed from the influence of immigrants considering the combination of climate, races of the animals, quality and specificity of milk, technological cheese-making processes and environmental microbiology, among other factors. It resulted in cheese products with specific physicochemical, microbiological, and sensory quality, which represent the heritage and identities of the different Brazilian regions. The production of artisanal cheese increased in many Brazilian regions, mainly in the southeast, especially due to the traditional production and innovative development of new varieties of cheese. The microbiological quality and safety of raw-milk artisanal cheese continues to be a concern and many studies have been focusing on this matter. Special attention needs to be given to the cheeses produced by raw milk, since numerous reports raised concerns related to their microbiological safety. This fact requires attention and the implementation of strict hygiene practices on the production and commercialization, besides appropriate governmental regulations and control. However, more studies on the relationship between technological processes and microbiological properties, which results in a superior culinary quality and safety of artisanal Brazilian cheeses, are needed.

Biopreservation and probiotic potential of a large set of lactic acid bacteria isolated from Brazilian artisanal cheeses: From screening to in product approach

The increasing interest in products with functional properties has encouraged the search for new lactic acid bacteria (LAB) present in natural sources, as traditional fermented foods. In this study, a large set of wild LAB isolates (n = 220) from Brazilian artisanal cheeses (BAC) were assessed for their probiotic and biopreservation potential. First, the rational selection was performed. From the tested isolates, 92 (41.8 %) were resistant to low pH (2 and 3). These isolates were submitted to bile salt (0.4 % Oxgall powder) resistance, and 22 were selected and submitted to adhesion assays. The autoaggregation values ranged from 68.5-99% and were considered moderate to high (20-70 %). Hydrophobicity values varied significantly between LAB (5.0-64.3%), and seven isolates presented values higher than 40 %. All selected LAB (n=22) were capable of adhering to Caco-2 (> 70 %) cells, and none isolate displayed any tested gene for biogenic amine production. Most isolates (18/22) showed less than 1 log CFU reduction after passage through the simulated gastrointestinal tract (GIT) conditions. A total of twenty isolates satisfied key in vitro criteria to be considered as probiotics. A hierarchical cluster analysis (HCA) was performed, and two clusters were observed, showing high variability between Lactobacillus plantarum isolates regarding adhesion properties and survival to GIT stress and one influence of the source of isolation on these properties. After screening, the antimicrobial activity of Lb. plantarum (1QB77) was tested in microcheeses in which survival of two relevant pathogenic bacteria (Staphylococcus aureus and Listeria monocytogenes) was monitored along ripening and after a simulated GIT passage, concomitantly. L. plantarum (1QB77) has shown the ability to reach high counts (∼ 9 log CFU/g) at the end of ripening. This isolate was also able to reduce counts of S. aureus and L. monocytogenes in microcheeses in approx. 2.3 and 2.5 log CFU/g, respectively, until the 21st day of ripening; and about 3.2 and 3.5 log CFU/g after simulated GIT passage. Overall, the assessment of the probiotic properties of a large set of LAB was fundamental for gaining insights on the technological, functional, and potential regional traits of wild LAB isolates that can be used to develop starter cultures for tailored applications.

Brazilian artisanal cheeses are rich and diverse sources of nonstarter lactic acid bacteria regarding technological, biopreservative, and safety properties-Insights through multivariate analysis

In this study a total of 220 isolates of lactic acid bacteria (LAB) recovered from 10 types of Brazilian artisanal cheeses marketed in 4 main regions of Brazil were evaluated regarding their safety and ability to produce diacetyl (a precursor of aromatic compounds), exopolysaccharides (EPS; from different sugar sources), and antagonistic activity against Listeria monocytogenes and Staphylococcus aureus. The results indicated that 131 isolates (59.6%) were classified as strong (40.5%) and moderate (19.1%) diacetyl producers; 28 isolates (12.7%) stood out due to their remarkable production of EPS from different sugars, including sucrose (3.2%), fructose (2.3%), lactose (2.3%), and glucose (6%). Furthermore, 94.1% and 95.9% of isolates presented antagonistic activity against S. aureus and L. monocytogenes, respectively, even though only 27 isolates (12.3%) exhibited positive results in the bacteriocin production test. None of the isolates tested presented hemolytic activity, and 117 were classified as safe, due to their intrinsic resistance to a maximum of 4 different antibiotics. The data obtained for assessment of antibiogram profile and technological potential (moderate and high production of diacetyl, EPS, and bacteriocins) were submitted to a multiple correspondence analysis to correlate them with the cheese of isolation. Regarding the antimicrobial profile of LAB strains, it was possible to verify an association between isolates from Minas artisanal cheeses from Araxá and resistance to tetracycline; Minas artisanal cheeses from Serro and resistance to erythromycin; Coalho and Minas artisanal cheese from Cerrado and resistance to penicillin; and isolates from Serrano and Colonial cheeses with clindamycin and ceftazidime resistance. Although the susceptibility of strains to these antibiotics was considered high (71.8-80.5%), these data may be related to the horizontal transfer of genes in the production chain of these cheeses. Results of multiple correspondence analysis also showed that isolates with antagonistic activity were mostly isolated from Manteiga, Colonial, and Coalho cheeses. The isolates with high or moderate EPS-producer ability from sucrose, glucose, and fructose were mainly associated with Minas artisanal cheeses from Cerrado. In contrast, isolates with high or moderate EPS-producer ability from lactose were isolated from Serrano, Minas artisanal cheeses from Canastra, and Campo das Vertentes microregions. Finally, isolates from Minas artisanal cheeses (from Araxá microregion), Coalho, and Caipira cheeses were associated with moderate/high diacetyl production. To the best of the authors' knowledge, this study provides, for the first time, data indicating that the dominant technological, biopreservative, and safety properties of LAB isolates can be correlated with the type of Brazilian artisanal cheeses, which denotes its singularity. This knowledge is of utmost relevance for the development of starter or adjunct cultures with tailored properties.

Viability of Staphylococcus aureus and expression of its toxins (SEC and TSST-1) in cheeses using Lactobacillus rhamnosus D1 or Weissella paramesenteroides GIR16L4 or both as starter cultures

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.

Safety and probiotic functionality of isolated goat milk lactic acid bacteria

Purpose

Lactic acid bacteria (LAB) are traditionally employed in the food industry. LAB strains from goat milk may also present probiotic potential, and it is fundamental to study the safety and functionality aspects which are desirable for their use in food. The objective of this study was to verify the probiotic potential of lactic bacteria isolated from goat milk.

Methods

The presence of safety-related virulence factors (hemolytic activity, gelatinase production, coagulase, and sensitivity to antibiotics) as well as functionality (exopolysaccharide (EPS) production, proteolytic activity, autoaggregation, gas production, survival in the gastrointestinal tract, and antimicrobial activity against bacteria that impair oral health) were determined.

Result

The selected LAB strains are safe against the evaluated parameters and have characteristics of possible probiotic candidates. Especially L. plantarum (DF60Mi) and Lactococcus lactis (DF04Mi) have potential to be added to foods because they have better resistance to simulated gastrointestinal conditions. In addition, they are isolated with already proven antimicrobial activity against Listeria monocytogenes, an important food-borne pathogen. DF60Mi was able to produce EPS (exopolysaccharides). LS2 and DF4Mi strains, both Lactococcus lactis subsp. lactis, demonstrated antimicrobial activity against S. mutans ATCC 25175, a recurrent microorganism in oral pathologies, mainly caries.

Conclusion

This study provides subsidies for future exploration of the potentialities of these LAB strains for both the development of new functional foods and for application in oral health.

Control of pathogens in fresh pork sausage by inclusion of Lactobacillus sakei BAS0117

A pork sausage was produced with low sodium content (1.64%) to which Lactobacillus sakei was added with the aim of developing a meat pork sausage for cooking and having technological, organoleptic, and hygienic advantages. The lactic acid bacteria (LAB) L. sakei, Lactococcus sp., and Pediococcus pentosaceus were submitted to extreme pH, temperature, and NaCl conditions. Lactobacillus sakei was used in pork sausage because of its resistance to different culture conditions and its antimicrobial potential. The food-borne pathogens Listeria monocytogenes Scott A, Enterococcus faecalis, and Staphylococcus aureus were used as indicator microorganisms to evaluate the antimicrobial activity of selected LAB strains. Salmonella enterica serotype Choleraesuis is a common pathogen of pigs. To the raw sausage product containing L. sakei and nonpathogenic endogenous microbiota, we added about >10⁴ and <10⁵ CFU/g of S. enterica serotype Choleraesuis to evaluate the inhibitory potential of L. sakei towards this pathogen. Salmonella Choleraesuis was inhibited in the presence of L. sakei over 7 days of storage of the meat product (about 3.0 log cycles reduction). Lactobacillus sakei significantly increased inhibition when compared with the nonfermented sausage. Thus, L. sakei BAS0117 played an important role as an additional hurdle in the fermented meat pork sausage during storage.

Short communication: In vitro and in vivo probiotic potential of Lactobacillus plantarum B7 and Lactobacillus rhamnosus D1 isolated from Minas artisanal cheese

Some Lactobacillus strains may contribute to the health of the host when administered in adequate concentrations, demonstrating their probiotic potential. In contrast, Listeria monocytogenes is a foodborne pathogen that can cause enteropathy, meningoencephalitis, abortion, and septicemia. The aim of this survey was to evaluate the in vitro and in vivo probiotic potential of Lactobacillus plantarum B7 and Lactobacillus rhamnosus D1, isolated from Minas artisanal cheese of the Serra da Canastra (Minas Gerais, Brazil), against Lis. monocytogenes. We submitted B7 and D1 to in vitro testing (antibiogram, tolerance to bile salts and artificial gastric fluid, and spot-on-lawn) and in vivo testing (relative weight gain in mice). Both Lactobacillus strains demonstrated in vitro inhibitory activity against Lis. monocytogenes, as well as sensitivity to antimicrobials and resistance to gastric acids and bile salts. In the in vivo assays, mice treated with D1 gained more weight than mice in the other groups. These results indicate that D1 could have higher probiotic potential than B7 because improvements in feed conversion may help animals fight infection.

In vitro assessment of the probiotic potential of lactobacilli isolated from Minas artisanal cheese produced in the Araxá region, Minas Gerais state, Brazil

ABSTRACT Minas artisanal cheese is made from endogenous starter cultures, including lactic acid bacteria (LAB). Some LAB may possess probiotic potential. Thus, this study aimed to evaluate the in vitro probiotic properties of lactobacilli isolated from Minas artisanal cheeses produced in Minas Gerais. Ten samples of lactobacilli, formerly isolated from those cheeses, were submitted to the following assays: antimicrobial susceptibility, tolerance to artificial gastric juice and biliary salts, production of hydrogen peroxide and antagonism against pathogenic and non-pathogenic micro-organisms. Only L. plantarum (C0) was sensitive to all tested antimicrobials, while the other LAB samples were resistant to at least one drug. Six samples were tolerant to artificial gastric juice, and L. brevis (A6) even grew in that medium. Three samples were tolerant to biliary salts. Only L. brevis (E35) produced hydrogen peroxide. Difference (P< 0.05) was observed among the means of inhibition haloes of lactobacilli against Enterococcus faecalis ATCC 19433 and Lactobacillus plantarum C24 in spot-on-the-lawn assay. All samples of lactobacilli inhibited Escherichia coli ATCC 25922, Salmonella enterica var. Typhimurium ATCC 14028 in co-culture antagonism test (P< 0.0001). Most lactobacilli samples showed in vitro probiotic potential. From the tested samples, L. brevis (A6) presented the best results considering all in vitro probiotic tests.

ANÁLISE SANITÁRIA E FÍSICO-QUÍMICA E ADEQUAÇÃO BACTERIOLÓGICA DO QUEIJO MINAS ARTESANAL PRODUZIDO EM DUAS PROPRIEDADES

Resumo Objetivou-se descrever as condições higiênico-sanitárias de queijarias artesanais, determinar os parâmetros físico-químicos, bacteriológicos e o período mínimo de maturação que garanta a inocuidade de queijos minas artesanais produzidos em Uberlândia-MG. Foram analisados, até aos 26 dias de maturação, queijos de duas propriedades, antes e após treinamento em boas práticas, totalizando 10 lotes (fabricações) com 12 queijos cada. Foram realizadas análises físico-químicas e bacteriológicas nos queijos e análises bacteriológicas em amostras ambientais. Até 26 dias de maturação, o queijo foi classificado como gordo e de baixa umidade, mas, considerando a maturação até 10 dias (período de comercialização usual), são gordos com média umidade. O tempo de maturação influenciou nos índices físico-químicos, com exceção da gordura no extrato seco. Análises bacteriológicas ambientais demonstraram higiene deficiente e falhas ou ausência no tratamento da água. A maturação e o treinamento influenciaram na redução de coliformes totais e e. coli, mas não de Staphylococcus coagulase positiva, não sendo possível determinar um período de maturação mínimo que garantisse o atendimento à legislação. As análises físico-químicas demonstraram variações esperadas, como a redução do percentual de umidade, e as análises bacteriológicas refletiram o treinamento aplicado aos manipuladores, já que houve redução nas contagens de coliformes totais e E. coli. Contudo, para garantir a inocuidade do produto, é necessário um conjunto de ações que incluem reforço e repetição dos treinamentos, registro das atividades, rastreabilidade, associadas ao monitoramento e fiscalização regular.

Milk fermented by Lactobacillus species from Brazilian artisanal cheese protect germ-free-mice against Salmonella Typhimurium infection

Ingestion of milks fermented by Lactobacillus strains showing probiotic properties is an important tool to maintain gastrointestinal health. In this study, Lactobacillus rhamnosus D1 and Lactobacillus plantarum B7, isolated from Brazilian artisanal cheese, were used as starters for the functional fermented milks to assess their probiotic properties in a gnotobiotic animal model. Male germ-free Swiss mice received a single oral dose of milk fermented by each sample, and were challenged with Salmonella Typhimurium five days afterwards. Milk fermented by both Lactobacillus strains maintained counts above 108 cfu/ml during cold storage. Lactobacillus strains colonised the gut of the germ-free-mice, maintaining their antagonistic effect. This colonisation led to a protective effect against Salmonella challenge, as demonstrated by reduced pathogen translocation and histological lesions, when compared to control group, especially for Lactobacillus rhamnosus D1. Additionally, mRNA expression of inflammatory (interferon gamma, interleukin (IL)-6, tumour necrosis factor alpha) and anti-inflammatory (transforming growth factor β1) cytokines was augmented in animals previously colonised and then challenged, when compared to other experimental groups. Lactobacillus plantarum B7 colonisation also promoted higher expression of IL-17, showing a proper maturation of colonised germ-free-mice immune system. IL-5 was stimulated by both strains’ colonisation and not by S. Typhimurium challenge.

Enumeration, identification and safety proprieties of lactic acid bacteria isolated from pork sausage

Lactic Acid Bacteria (LAB) are indigenous microorganisms occurring in pork sausages. The utilization of selected autochthonous LAB may improve the safety of meat products. This study aims to enumerate and identify LAB in pork sausage and to characterize their safety properties, such as antimicrobial susceptibility and antibacterial activity. A total of 189 sealed packages of pork sausages were collected in seven municipalities (27 samples in each city) of Minas Gerais, Brazil. Microbiological analyses were performed to enumerate LAB. Two pre-selection criteria were applied to 567 isolates of LAB: catalase activity and tolerance to pH 2. A total of 32 strains of UFLA SAU were selected, characterized phenotypically and identified through 16S rDNA region sequencing. The susceptibility to antimicrobial and antibacterial activities of isolates was evaluated. The LAB count ranged from 3.079 to 8.987 log10 CFU/g. Lactobacillus plantarum and Lactobacillus paracasei were identified in the samples. UFLA SAU 11, 20, 34, 86, 131 and 258 showed a profile of susceptibility to four antimicrobials: erythromycin, ampicillin, chloramphenicol and gentamycin. In the antibacterial activity test, with exception of UFLA SAU 1, all other strains showed efficiency in inhibiting Escherichia coli, Salmonella Typhiand Listeria monocytogenes. In the statistical analysis there was interaction among strains of Lactobacillus against the pathogens tested. L. monocytogenes (P=0.05) was more sensitive to Lactobacillus strains and the highest inhibitory activity against this pathogen was achieved by strains UFLA SAU 135, 226, 238 and 258. Thus, UFLA SAU 11, 20, 34, 86, 131, 135, 226, 238 and 258 possess safety characteristics for application in meat products.

Propriedades probióticas in vitro de Lactobacillus spp. isolados de queijos minas artesanais da Serra da Canastra - MG

O objetivo deste estudo foi determinar o potencial probiótico in vitro de Lactobacillus spp. isolados de queijos minas artesanais da Serra da Canastra, considerando-se o antagonismo entre amostras isoladas frente a microrganismos indicadores, a susceptibilidade a antimicrobianos, a sensibilidade ao ácido gástrico e a sensibilidade a sais biliares. Todas as bactérias ácido-lácticas testadas apresentaram resistência ao ácido gástrico (pH 2,0) e aos sais biliares (0,3%), bem como atividade antagonista contra Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica var. Typhimurium, Enterococcus faecalis e bactérias ácido-lácticas isoladas dos próprios queijos - Lactobacillus plantarum (D27) e Lactobacillus rhamnosus (B25). Todas as amostras foram sensíveis à eritromicina e tetraciclina e resistentes à ciprofloxacina, gentamicina, oxacilina, estreptomicina e vancomicina. L. plantarum(B17) apresentou melhor potencial probiótico, pois obteve resultados satisfatórios em todas as propriedades avaliadas. Mais estudos são necessários para verificar a presença e a capacidade de transmissão de genes de resistência antimicrobiana a outros microrganismos e para avaliar o potencial dos microrganismos in vivo. As bactérias selecionadas poderão ser utilizadas na elaboração de queijos em que sejam mantidos o sabor e a tradição do queijo minas artesanal do estado de Minas Gerais.