Traditional fermented products - a good dource for beneficial lactic acid bacteria

Modern diets of the western world are very different than the traditional ones which many researchers and consumers are now realizing that the latter are not only nutritious but also can provide benefits beyond their nutritional properties. Almost all current eating regimes of modern societies include the consumption of elevated amounts of processed foods and ready-to-eat products that contain numerous chemicals or refined additives (such as conservants, stabilizers, emulsifiers, salts, carbohydrates) that are used to increase shelf-life, flavour and physical properties. In addition, most people do not follow proper eating guidelines and fast for long periods of time and then overeat afterwards instead of eating several smaller meals throughout the day. All of these unhealthy foods and bad eating habits are important causes of the increase incidence of obesity, high cholesterol levels in blood, high blood pressure, diabetes and many other health problems including certain types of cancers. At the same time traditional fermented food products that contain low levels of preservatives and can provide health promoting benefits have only recently been reincorporated as part of normal diets. Traditional fermented foods such as bread, cheese, salami, olives, beer and wine, have been prepared and consumed for thousands of years using locally available materials and more importantly the methods of preparation are strongly linked to culture and tradition; the preparation of these foods still remains a household art in many isolated regions and are normally passed down from generation to generation. These foods have special organoleptic qualities and some even possess health promoting properties due to the presence of a biologically diverse microbiota, especially Lactic Acid Bacteria (LAB) present in the raw material or as a contaminant from the producers or instruments used to prepare them. These microorganisms are important genetic reservoirs and hold great biotechnological and health improving potentials that should be exploited. These beneficial microorganisms are not only involved in modifying the sensorial and technological aspects of foods, mainly through the release of lactic acid and flavour compounds, but many exhibit probiotic properties. Because of the numerous beneficial properties that have been attributed to LAB, these are the most commonly used probiotic microorganisms that can have been defined by the World Health organization as live microorganisms which when administered in adequate amounts confer a health benefit on the host. Some of the health claims attributed to probiotics include the improvement of the normal microbiota and stabilization of the gut mucosal barrier, prevention of infectious diseases and food allergies, hypocholesterolemic, anti-mutagenic and anti-carcinogenic properties, immune system modulation, prevention of inflammatory bowel diseases, and alleviation of lactose intolerance. They have also been shown to provide essential compounds such as vitamins, hydrolytic enzymes, bacteriocins, and other bioactive compounds. Nowadays, most probiotic foods are milk-based, although many fermented cereals, with added probiotic cultures, are now appearing in specialized markets. However, only limited knowledge of LAB content in traditional fermented food products is currently available and very little has been done in the line of searching these products as a natural source of beneficial LAB. Cereals have a high nutritional value (vitamins, proteins, dietary fiber, energy, and minerals) and are cultivated on more than 73 % of agricultural soil while contributing to more than 60 % of the world?s food production. LAB are frequently involved in the fermentation of the cereals and these products have a long history of use in traditional medicine because of their beneficial properties. Other fermented food products such as salami, cheese, fruits and vegetables can be a good source of beneficial LAB as well. Consumers can appreciate the highly organoleptic and nutritional characteristics of these products and in the same time can be consuming a high number of LAB with beneficial characteristics. LAB may contribute to the extension of the self life of the products by producing various antimicrobial substances, including bacteriocins, lactic acid, hydrogen peroxide, fatty acids, diacetyl and other low molecular weight compounds during fermentation. In fact LAB can have play beneficial role in the production and conservation of the food products from one side and been beneficial for the consumers as a probiotic on the later stage. It was demonstrated that without even knowing the basic theories of microbiology, ancient populations were able to optimize the biotechnological aspects of fermentation giving rise to foods and beverages that were not only useful because of their nutritive and social aspects, but also provided health-promoting and curative properties, many of which are just recently being described by concrete scientific research. These foods thus merit further scientific investigations in order to understand exactly which microorganisms could be useful to be used as biotechnological tools for the development of new and improved foods or used as novel fountains of beneficial LAB that could be used in a wide range of probiotic applications.Fil: Todorov, Svetoslav Dimitrov. Universidade de Sao Paulo; BrasilFil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin

Effect of Growth Medium on Bacteriocin Production by Lactobacillus plantarum ST194BZ, a Strain Isolated from Boza

The cell-free supernatant containing bacteriocin ST194BZ, produced by Lactobacillus plantarum ST194BZ, inhibits the growth of Lactobacillus casei, Lactobacillus sakei, Lactobacillus delbrueckii subsp. bulgaricus, Enterococcus faecalis, Escherichia coli, Enterobacter cloacae and Pseudomonas aeruginosa. Strain ST194BZ produces two bacteriocins, viz. ST194BZ(a) of 3.3 kDa and ST194BZ(b) of 14.0 kDa, based on tricine-SDS-PAGE. Reduction in bacteriocin activity was observed after treatment with proteinase K, trypsin and pronase, but not with catalase and a-amylase. A maximum total bacteriocin activity of 12 800 AU/mL was recorded after 14 h in MRS broth. In MRS broth adjusted to pH=5.5, 6.0 or 6.5, an equal level of bacteriocin production of 12 800 AU/mL was recorded. Optimal production (12 800 AU/ mL) was recorded in the presence of tryptone (20 g/L), a combination of tryptone and meat extract (1:0.6), or tryptone and yeast extract (1:0.6). Growth of strain ST194BZ in the presence of 10 or 20 g/L of D-mannose yielded bacteriocin levels of 12 800 AU/mL. In the presence of 30 or 40 g/L of mannose the activity levels doubled to 25 600 AU/mL. No difference in antibacterial activity was recorded when strain ST194BZ was grown in the presence of 2 g/L of K2HPO4 and 2 g/L of KH2PO4. Concentrations of 10, 20 and 50 g/L of KH2PO4 yielded double activity (25 600 AU/mL). Supplementing MRS with 1 g/L or more glycerol inhibited the production of bacteriocin. Growth in the presence of vitamins did not stimulate bacteriocin production. No plasmids were recorded for strain ST194BZ, suggesting that the genes encoding bacteriocin production are located on the genome

Exploration and Understanding of Beneficial Properties of Lactic Acid Bacteria: 10 years of experience in Applied Food Biotechnology

The scientific community is currently facing a more than exponential increase of knowledge in all areas and disciplines. In the last 10 years, the contribution of the journal Applied Food Biotechnology was eminent in distributing that knowledge by providing a tribune for researchers from different countries all over the world to share their ideas, observations, and hypotheses. With a focus on different aspects of applied and fundamental biological sciences, the journal Applied Food Biotechnology was established as a reference of the Iranian scientific community. In the last 10 years, the journal has been covering several topics related to exploring the beneficial properties of lactic acid bacteria (LAB) and their role in modern food technologies. LAB are already proven as a realization of Hippocrates' vision for the potential role of food in human and other animals' health. However, what will be the next frontier? What are the challenges in understanding the interactions between microbiota and host microorganisms? What will be the novel analytical tools, facilitating a new era of probiotic research? These were only a few research topics presented and discussed in Applied Food Biotechnology in the last decade. This editorial overview aims to celebrate the scientific contribution of Applied Food Biotechnology in the area of research associated with the beneficial properties of LAB, summarizing some of the studies published in the journal

Lactobacillus curvatus UFV-NPAC1 and other lactic acid bacteria isolated from calabresa, a fermented meat product, present high bacteriocinogenic activity against Listeria monocytogenes

Bacteriocins produced by lactic acid bacteria (LAB) can be considered as viable alternatives for food safety and quality, once these peptides present antimicrobial activity against foodborne pathogens and spoilage bacteria. Fermented foods, such as artisanal sausages and cured meats, are relevant sources of LAB strains capable of producing novel bacteriocins, with particular interest by the food industry.Three LAB strains (firstly named as Lactobacillus curvatus 12, L. curvatus 36 and Weissella viridescens 23) were obtained from calabresa by presenting promising bacteriocinogenic activity, distinct genetic profiles (rep-PCR, RAPD, bacteriocin-related genes) and wide inhibitory spectrum. Among these strains, L. curvatus 12 presented higher bacteriocin production, reaching 25,000 AU/mL after incubation at 25, 30 and 37 °C and 6, 9 and 12 h. Partially purified bacteriocins from L. curvatus 12 kept their inhibitory activity after elution with isopropanol at 60% (v/v). Bacteriocins produced by this strain were purified by HPLC and sequenced, resulting in four peptides with 3102.79, 2631.40, 1967.06 and 2588.31 Da, without homology to known bacteriocins.LAB isolates obtained from calabresa presented high inhibitory activity. Among these isolates, bacteriocins produced by L. curvatus 12, now named as L. curvatus UFV-NPAC1, presented the highest inhibitory performance and the purification procedures revealed four peptides with sequences not described for bacteriocins to date

Lukanka, a Semi-Dried Fermented Traditional Bulgarian Sausage: Role of the Bacterial Cultures in its Technological, Safety and Beneficial Characteristics

Background: Production of different fermented meat products is a well-known practice done in different European countries since ancient times. Fermentation of primary materials and/or smoking and salting processes are part of the preservation processes and is important for the formation of final products which is inherent in South European countries. Originally, fermentation of meat products is intended for preservation and safe storage for long periods of time. However, nowadays, gastronomical properties of fermented meat products are essential in obtaining specific flavor, odor, color and structure of the sausages which consumers highly prefer. Emphasis is given on gastronomic characteristics, which results from the various combination of raw meat, specific spices and the natural microbiota or conducted fermentation processes by application of specific starter cultures. Seven bacterial genera (Lactobacillus, Leuconostoc, Staphylococcus, Enterococcus, Lactococcus, Micrococcus and Streptococcus) are commonly used as meat starter cultures. Complex fermentation processes that occur during the ripening of the fermented meat products are the results of the interaction between bacterial starter cultures, remaining enzymes in the muscle and fat tissue and available bacterial enzymes. Objective: The present overview aims to provide information related to the characterization of the specific microbiota associated with lukanka, a naturally-fermented semi-dried Bulgarian sausage. What is the specificity of its fermentation processes; how do different starter and indigenous meat microbiota interfere to form specific final products; what is the role of starter and adjunct cultures in the safety of the products; how is the Bulgarian lukanka classified in the perspective of other Mediterranean dry fermented sausages? These are some of the questions that this review will discuss

Enhanced Bacteriocin Production by Pediococcus pentosaceus 147 in Co-culture With Lactobacillus plantarum LE27 on Cheese Whey Broth

The production of bacteriocins by lactic acid bacteria (LAB) has been of wide interest in the food industry due to their potential application in biopreservation. The production of bacteriocins is usually low in single strain fermentation, but can improve when the bacteriocinogenic strain is cultured in association with another bacteria. The present work aims to evaluate the growth and production of bacteriocins by Pediococcus pentosaceus 147 (bacteriocinogenic strain) in co-culture with Lactobacillus plantarum LE27 (inducer strain) using a culture medium based on cheese whey (CW). Strains were inoculated in co-culture in a CW broth at 7.24 Log CFU/mL of initial concentration of P. pentosaceus 147 and incubated at 37°C. Bacteriocin production was measured after 24 h by the critical dilution method, biomass was measured by plating on MRS agar (1% aniline blue), and a mono-culture was used as a control. The titers of bacteriocins produced by P. pentosaceus 147 in mono-culture were 19,200 AU/mL lower than those obtained in co-culture with Lb. plantarum LE27 at 51,200 AU/mL. The effect of adding the inducer strain at different times of incubation (3, 6, 9, and 12 h) was evaluated, with the addition of the induction factor at the beginning of the incubation of P. pentosaceus 147 generating the highest bacteriocin activity. This study shows the potential of inducing bacteriocinogenesis using co-cultures of strains of the genera Pediococcus and Lactobacillus and using alternative substrates such as cheese whey

In vitro evaluation of the safety and probiotic and technological potential of Pediococcus pentosaceus isolated from sheep milk

Six isolates (Ac1Pd, Ac3Pd, Ac4Pd, Ac5Pd, Ac7Pd, and Ac22Pd) of Pediococcus pentosaceus from sheep milk were tested for safety and for probiotic and technological potential. The results showed that none of the isolates were able to produce biogenic amines or virulence factors. The isolates tested showed low hydrophobicities, high auto-aggregation capacities and co-aggregation with L. monocytogenes ATCC 7644, L. sakei ATCC 15521 and E. faecalis ATCC 19444, but none produced ?-galactosidase and bacteriocins. The isolates did not show growth at pH values 3 and 12, while in a pH range from 4 to 10 the growth was variable. In the absence of bile, all the isolates showed growth, with suppression at bile concentrations of 0.1%, 0.3%, 0.6% and 1.0%. In the disc-diffusion test, the isolates tested were resistant to oxacillin, sulfatrimethoprim and vancomycin but were sensitive to chloramphenicol and tetracycline. The isolates showed variable responses to penicillin G and were resistant to most of the drugs tested, except for amoxicillin trihydrate and ibuprofen. All cultures showed a high milk-acidification capacity after 24 hours and none produced exopolysaccharides. The isolates of P. pentosaceus were able to produce diacetyl; however, no culture showed extracellular proteolytic activity and the autolysis varied from 21.3% to 30.5% after 24 h. The isolates grew at NaCl concentrations of 4.0 and 6.0%, but the growth was lower at 10.0%. Finally, all the isolates were found to be safe but had limited application as probiotics and in some technological uses

Comparison of bacteriocins production from Enterococcus faecium strains in cheese whey and optimised commercial MRS medium

The production of bacteriocins from cheap substrates could be useful for many food industrial applications. This study aimed at determining the conditions needed for optimal production of enterocins SD1, SD2, SD3 and SD4 secreted by Enterococcus faecium strains SD1, SD2, SD3 and SD4, respectively. To our knowledge, this is the first use of cheese whey—a low-cost milk by-product—as a substrate for bacteriocin production by E. faecium; skimmed milk and MRS broths were used as reference media. This cheese manufacturing residue proved to be a promising substrate for the production of bacteriocins. However, the levels of secreted antimicrobial compounds were lower than those achieved by E. faecium strains in MRS broth. Bacteriocin production was affected strongly by physical and chemical factors such as growth temperature, time of incubation, pH, and the chemical composition of the culture medium. The optimal temperature and time of incubation supporting the highest bacteriocin production was determined for each strain. Different types, sources and amounts of organic nitrogen, sugar, and inorganic salts played an essential role in bacteriocin secretion. E. faecium strains SD1 and SD2—producing high bacteriocin levels both in cheese whey and skimmed milk—could be of great interest for potential applications in cheese-making