Lactic Acid Bacteria Cultures Research Articles

Impact of Probiotic and Synbiotic Supplementation on the Physicochemical, Texture and Sensory Characteristics of Wheyless Domiati-Like Cheese

The effect of probiotic cultures of lactic acid bacteria in the absence and presence of Inulin on the quality of wheyless Domiati-like cheese made from dry dairy ingredients was assessed during 28 days of storage at 7oC. The treatments design was as follows: C, thermophilic starter of Streptococcus thermophillus and Lactobacillus delbreckuii subsp bulgaricus(standard control cheese); LR, Lactobacillusrhamnosus19070; LR+IN, Lbrhamnosuswith 2% inulin; BL, Bifidobacterium animalissubsp.lactis ATCC SD5219; and BL+IN, B. lactiswith 2% inulin. Differences in physicochemical characteristics, proteolysis indexes, rheological texture and sensory attributes were found among the assessed cheeses. Results showed that addition of both probiotic strains improved cheese quality, whereas incorporation of Inulin in synbiotic cheeses enhanced the texture and sensory attributes. Relative degrees of proteolysis were found to be significantly higher in synbiotic cheese than the control and probiotic cheeses. The sensory evaluation showed that the total perception of Domiati-like cheeses was improved by the addition of the probiotics alone or in combination with Inulin. It is suggested that wheyless Domiati-like cheese fortified with probiotics and prebiotics well orientated functional food had accepted composition and sensory properties.

INNOVATION MANAGEMENT BIOTECHNOLOGY OF STARTER CULTURES

According to experts, one of the innovative directions of the development of food biotechnology is the development of biotechnological approaches to the production of probiotics, prebiotics, synbiotics, ferments and food ingredients, new strains of lactic acid and other technological microorganisms, microbial consortia with predetermined biological properties and optimized processing characteristics. The inclusion of polycomponent probiotic consortia bacterial preparations from cultures of lactic acid bacteria into foods can be the basis for the prevention of various diseases. Experts predict the start of production of probiotic products with proven efficiency in Russia by 2017 and their mass production by 2020. The use of lactic acid bacteria as starter cultures of direct application and having necessary range of features will improve the functional-and-technological and consumer properties of dairy products. The paper deals with the study of physiological-and -biochemical and commercially valuable properties of strains of lactic acid bacteria when creating combined starter cultures of direct inoculation with high proteolytic activity. It has been found that the lactic acid bacteria of Lactococcus lactis subspecies cremoris B 2276, Lactobacillus plantarum B 3242, Lactococcus lactis B 5946 and Leuconostoc mesenteroides subspecies mesenteroides B 8404 have high proteolytic activity contributing to the formation of low molecular weight peptides and free amino acids in milk and show high antagonistic activity against sanitary significant intestinal microorganisms (Staphylococcus aureus, Proteus vulgaris, Escherichia coli). The results on the study of biocompatibility show the lack of inhibitory effect which allows their use in preparing the combined starter of direct inoculation.

Production of organic flavor compounds by dominant lactic acid bacteria and yeasts from Obushera, a traditional sorghum malt fermented beverage.

Single and mixed starter cultures of lactic acid bacteria (LAB): Weissella confusa MNC20, Lactobacillus plantarum MNC21, Lactococcus lactis MNC24 and Lactobacillus fermentum MNC34 and yeasts: Issatchenkia orientalis MNC20Y and Saccharomyces cerevisiae MNC21Y were used to produce Obushera, a fermented sorghum beverage. Microbial counts, pH, sugars, organic acids, and volatile compounds in starter culture and spontaneous fermentations were monitored during 48 hrs. Maximum counts of LAB (8.4–9.4 log cfu g−1) and yeasts (7.5 ± 0.1 cfu g−1) starter cultures were attained in 6–48 hrs. Weissella confusa, Lc. lactis, and Lb. fermentum showed possible acid sensitivity while I. orientalis produced surface films. LAB starter cultures and their combinations with S. cerevisiae lowered pH from 5.83 to <4.5 (3.50–4.13) in a shorter time (12 hrs) than spontaneous fermentations (24 hrs). Lactococcus lactis and W. confusa metabolized glucose the fastest (p < .05) during the first 6 hrs. Lactobacillus fermentum, Lb. plantarum, and S. cerevisiae utilized glucose and maltose concurrently. Lactobacillus plantarum and S. cerevisiae additionally utilized fructose. S. cerevisiae metabolized sugars the fastest (p < .05) during the first 12–24 hrs. Lactobacillus plantarum and W. confusa produced the highest (p < .05) amounts of lactate (5.43 g kg−1) and diacetyl (9.5 mg kg−1), respectively. LAB also produced acetate, ethanol, acetaldehyde, acetone, and acetoin. Coculturing LAB with S. cerevisiae reduced (p < .05) lactate and diacetyl yield. Yeasts produced high amounts of acetaldehyde and methyl alcohols. Issatchenkia orientalis produced higher (p < .05) amounts of 2‐methy‐1‐propanol and 3‐methyl‐1‐butanol than S. cerevisiae. Combinations of LAB with S. cerevisiae produced a profile flavor compounds close to that of spontaneously fermented Obushera. These combinations can be adopted for controlled fermentation of Obushera and related fermented cereal products.

Antimicrobial activity of lactic acid bacteria multiplied in an alternative substrate and their influence on physiological parameters of new-born calves

Here, the ability of Pediococcus pentosaceus and Pediococcus acidilactici to utilise potato tuber juice for cell synthesis without an external nutrient supplement was investigated, and the influence of lactic acid bacteria (LAB) grown in this substrate on the growth performance of new-born calves, as well as blood biochemical and faecal microbiological parameters was evaluated. Calves were selected based on the analogy principle, treatment group (n = 21), control group (n = 27). Calves in the treatment group were administered 50 ml of fermented potato tubers juice containing 9.6 log CFU/ml of LAB mixture for 14 days. Also, determination of antimicrobial activities of tested LAB against a variety of pathogenic and opportunistic bacterial strains previously isolated from diseased cattle was performed. It was found that LAB supernatants effectively inhibited the growth of Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Salmonella enterica, Corynebacter spp., Klebsiella pneomoniae, Enterococcus faecalis, and Bacillus cereus (the diameters of the inhibition zones varied between 11.0 ± 0.3 mm and 17.0 ± 0.6 mm). Thus, potato juice can be used as an alternative substrate for LAB cultivation (LAB cell concentration 9.6 ± 0.07 log CFU/ml). After lyophilisation (-48 °C) and spray-drying (+150 °C) viable cell concentrations in the fermented potato juice powder were 9.18 ± 0.09 log CFU/g and 9.04 ± 0.07 log CFU/g, respectively. The 50 ml of fermented potato tuber juice containing 9.6 log CFU/ml of LAB, administered every day for 14 days, reduced the risk of developing acidosis (stabilised blood pH; P < 0.05), reduced lactates and PCO2 concentration (P < 0.05) and the risk of liver lesions (reduced serum alanine aminotransferase concentration; P < 0.005) in blood and E. coli in the faeces of new-born calves.

유산균 배양액 추출액의 항병원성균 효과 및 냉장저장 육제품의 품질에 미치는 효과

유산균 배양액 추출액의 항병원성균 효과 및 냉장저장 육제품의 품질에 미치는 효과

БІОТЕХНОЛОГІЯ СТВОРЕННЯ ВІТЧИЗНЯНИХ БАКТЕРІАЛЬНИХ ПРЕПАРАТІВ ДЛЯ МОЛОЧНОЇ ПРОМИСЛОВОСТІ УКРАЇНИ

У статті висвітлені результати біотехнологічних досліджень конструювання нового бактеріального препарату для виробництва бринзи в промислових умовах.&#x0D; Проведено скринінг 106 культур молочнокислих бактерій (МКБ) виділених із традиційної бринзи виготовленої у непромислових умовах із овечого молока у Карпатському регіоні України.&#x0D; При відборі штамів МКБ для конструювання складу бактеріального препарату за технологічними властивостями враховували ступінь і швидкість кислотоутворення та стійкість культур мікроорганізмів до підвищених концентрацій NaCl – 4 і 6,5%.&#x0D; В результаті проведених досліджень відібрано п’ять штамів МКБ, які були найстійкішими до високих концентрації NaCl (6,5%) та проявляли високу кислотоутворювальну активність. Lactococcus lactis ssp. lactis SB 44 – 98 °Т;Enterococcus faecium SB 12 – 86 °Т; Lactobacillus plantarum SB 17 – 85 °Т; Leuconostoc mesenteroides ssp. mesenteroides SB 8 – 70 °Т; Lactococcus garvieae SB 26 – 67 °Т.&#x0D; Встановлено оптимальне співвідношення МКБ Lac. lactis ssp. lactis – 50%, Lbc. plantarum – 15%, E. faecium –20%, Leuc. mesenteroides ssp. mesenteroides – 10% та Lac. garvieae – 5% у складі бактеріального препарату, що забезпечує найкращі споживчі характеристики готовому продукту.&#x0D; Виробництво бринзи із підібраним консорціумом мікроорганізмів, який є типовою мікрофлорою для традиційного карпатського сиру бринза, дозволяє отримати безпечний та якісний харчовий продукт, який відповідає вимогам згідно з ДСТУ 7065:2009 і забезпечує збільшення чисельності життєздатних МКБ до 5,2х107 КУО/г продукту.&#x0D;

Development of a simple, low-cost and eurytopic medium based on Pleurotus eryngii for lactic acid bacteria.

Lactic acid bacteria (LAB) are a group of important beneficial microorganisms for human, but their growth is restricted to the habitats with rich nutrients. In order to develop a simple, low-cost and efficient medium based on the mushroom Pleurotus eryngii, this study evaluated the effects of different treatment methods for the mushroom, concentration of the mushroom, buffers, tween 80, MgSO4·7H2O, MnSO4·4H2O, CuSO4·5H2O, riboflavin and ascorbic acid on the growth of Lactococcus lactis subsp. lactis SLPE1-3. An optimized medium was developed, which was composed of the mushroom at 200 g/L, the buffer sodium acetate at 5 g/L, and riboflavin at 0.5 mg/L. The mushroom was ground, boiled and filtered for the filtrate in advance. In this optimized medium which was named as PSR medium, the population density of SLPE1-3 sharply reached 2.13 × 109 CFU/mL within 18 h of incubation, and still maintained 1.17 × 108 CFU/mL at 120 h. In addition, this study found that 6 kinds of LAB could grow almost well, and maintained high survival in PSR medium compared to M17 or MRS medium, including Lactococcus lactis subsp. lactis, Lactobacillus plantarum, Lactococcus lactis subsp. cremoris, Lactobacillus paracasei, Pediococcus pentosaceus and Lactobacillus rhamnosus. These results showed that PSR medium was a simple, low cost and eurytopic medium for the cultivation of LAB, and could replace MRS or M17 medium in the food industry, biomedicine and laboratory.

Sauerkraut: A Probiotic Superfood

Background: Sauerkraut could potentially be a probiotic superfood. Sauerkraut does not require the use of a starter culture to cultivate these beneficial bacteria. All that is needed is a measure of salt and the cabbage. Naturally made, unprocessed sauerkraut contains probiotic microorganisms called Lactic Acid Bacteria (LAB). LAB is one of the most significant organisms and has established benefits. For example, Lactic Acid Bacteria has established benefits with the treatment of diarrhea, constipation, irritable bowel syndrome, infections (urogenital, urinary and candida). LAB have also been shown to enhance immune system function to help prevent various illnesses and promote lactose digestion. Nevertheless, there is very little conclusive evidence on how much LAB is in sauerkraut and if there is enough present to confer benefits. Purpose: Determine if various serving sizes of homemade sauerkraut (2 Tbsp., 1⁄2 cup, &amp; 1 cup) meets the recommended CFU range in comparison to a control (supplement probiotic). Methods: Sauerkraut was prepared with no starter culture. Modified Lactobacillus Media was used to culture LAB. The capsule serving (0.8g) was diluted with 99.2g PBS (1/100) and 10g of sauerkraut was diluted with 90g PBS (1/10). For serial dilutions, 1mL of each of the samples was diluted into 9 mL MRS broth for the dilutions (10-1-10-10). Then 1mL from each test tube is transferred into corresponding petri dishes. Melted Lactobacillus MRS agar is then mixed into each of the petri dishes. All petri dishes are then placed into a candle light jar and placed in an incubator at 37 degrees Celsius (98.6oF) for 5 days. After five days, the petri dishes with 25-250 visible cultures were counted. The number counted was multiplied by the dilution which gave the total number CFUs/g. The LAB concentration of the sauerkraut was calculated by multiplying the CFU/g times the serving size. Results: The results were calculated as the mean of CFUs recorded from the 3 trials for both the control (supplement) and the sauerkraut. The control group was calculated as a mean of 4.3x107 CFUs with a Relative Standard Deviation (RSD) of 3.5% CFUs. The sauerkraut averages were calculated for each of the serving sizes. The 2 Tbsp. serving has a mean of 1.5x106 (RSD= 32%), the 1⁄2 cup has a mean of 5.9x106 (RSD= 31%), and the 1 cup serving has a mean of 1.2x107 (RSD= 30%). Conclusion: The study concludes that sauerkraut (even the two Tbsp. serving) meets the recommended CFU range. Based on these findings, sauerkraut can be considered a “probiotic superfood”. Keywords: Sauerkraut, probiotic superfood, supplement probiotic, Lactobacillus

Antimicrobial susceptibility and antibiotic resistance profiles of cultivable lactic acid bacteria from intestinal tract of domestic chickens collected in Adjara

Abstract Elaboration and introduction of safe, effective probiotic preparations as alternatives to antibiotics are being actively conducted throughout the world. 66 LAB isolates were isolated from ileal, cecal and rectal samples collected from domestic chickens collected in different districts of Adjara, Georgia. Their resistance to 17 antibiotics and antibacterial activity were studied using the agar diffusion method. Among the isolates, widespread resistance was found to metronidazole and nystatin, sensitivity – to ampicillin, tylosin, rifampicin and bacitracin. Most of isolates have intermediate susceptibility to the majority of the antibiotics. 3 LAB isolates were selected by antibacterial action against the several bacterial indicator strains that makes them effective remedy to control antibiotic-independent pathogen through competitive exclusion and promotion of good protective microbiota and perspective probiotic additives for chicken food. Future investigations, proving the safety of the strains and their antimicrobial compounds will enable to apply in vivo probiotic properties on poultry production.

Control of Zymoseptoria tritici cause of septoria tritici blotch of wheat using antifungal Lactobacillus strains.

This study explored an effective biological control agent based on lactic acid bacteria culture or culture supernatant, which was effective against fungicide-resistant Zymoseptoria tritici, which causes septoria tritici blotch (STB). Three lactic acid bacteria strains which exhibited broad antifungal activity were investigated for their potential to control Z.tritici. Plateassays, liquid culture growth inhibition assays and STB biocontrol seedling tests were employed. Lactobacillus brevis JJ2P and Lactobacillus reuteri R2 caused significant fungal inhibition as observed by large mycelium clearing on modified MRS agar. Cell-free culture supernatants of Lact.brevis JJ2P and Lact.reuteri R2 showed antifungal activity against Z.tritici, as observed by mycelial radial growth inhibition and liquid culture growth inhibition. Cell-free supernatants of these anti-Z.tritici LAB strains were assessed invivo for their abilities to inhibit STB development in seedling tests. Lact. brevis JJ2P was capable of inhibiting disease development and significantly reduced the diseased leaf area covered with pycnidia. Biological control accomplished by beneficial micro-organisms such as Lact.brevis JJ2P may represent an alternative control strategy for reducing STB. Globally, STB is regarded as one of the most important diseases of wheat. Control of Z.tritici is heavily reliant on fungicide application. The recent emergence of resistance or reduced sensitivity to fungicides among Z.tritici populations has urgently called for the development of new control strategies.

The impact of lactic acid bacteria with antimicrobial properties on biodegradation of polycyclic aromatic hydrocarbons and biogenic amines in cold smoked pork sausages

The influence of surface treatment with lactic acid bacteria (LAB), previously cultivated in an alternative substrate, on the formation of polycyclic aromatic hydrocarbons (PAHs) and biogenic amines (BAs) in cold smoked pork meat sausages was investigated. Moreover, sausages treatment with LAB after the smoking on PAHs content changes was evaluated. Additionally, the inhibitory effects of LAB metabolites on food spoilage bacteria was determined using the agar well diffusion assay method. The metabolites of Pediococcus acidilactici KTU05-7, Pediococcus pentosaceus KTU05-9 and Lactobacillus sakei KTU05-6 strains showed good inhibitory properties against tested pathogenic and food spoilage bacteria. Moreover L. sakei produced bacteriocins inhibited the growth of Pseudomonas aeruginosa and Escherichia coli. Furthermore, the treatment of sausages surface with LAB before smoking decreased the content of cadaverine and spermidine, whereas the treatment of sausages surface with LAB after smoking decreased the content of putrescine (approx. 53% when L. sakei and P. acidilactici were applied) or totally eliminated (applying P. pentosaceus) from outer layers and centre of sausages. The application of LAB for sausages treatment before and after smoking significantly decreased both benzo[a]pyrene and chrysene decreasing (p < 0.05). The results also confirm that potatoes juice could be used as an alternative substrate for LAB cultivation, and the obtained fermented bioproducts could be applied for surface treatment of cold smoked pork sausages in case to reduce microbial contamination, and PAHs content in final product.

Modelling and predicting the simultaneous growth of Escherichia coli and lactic acid bacteria in milk.

Modelling and predicting the simultaneous competitive growth of Escherichia coli and starter culture of lactic acid bacteria (Fresco 1010, Chr. Hansen, Hørsholm, Denmark) was studied in milk at different temperatures and Fresco inoculum concentrations. The lactic acid bacteria (LAB) were able to induce an early stationary state in E. coli The developed model described and tested the growth inhibition of E. coli (with initial inoculum concentration 10(3) CFU/mL) when LAB have reached maximum density in different conditions of temperature (ranging from 12 ℃ to 30 ℃) and for various inoculum sizes of LAB (ranging from approximately 10(3) to 10(7) CFU/mL). The prediction ability of the microbial competition model (the Baranyi and Roberts model coupled with the Gimenez and Dalgaard model) was first performed only with parameters estimated from individual growth of E. coli and the LAB and then with the introduced competition coefficients evaluated from co-culture growth of E. coli and LAB in milk. Both the results and their statistical indices showed that the model with incorporated average values of competition coefficients improved the prediction of E. coli behaviour in co-culture with LAB.

Sensory profile development of Oaxaca cheese and relationship with physicochemical parameters

A sensory profile of Oaxaca cheese was developed. To represent both industrial and artisanal Oaxaca cheese, 3 types of cheese were manufactured under controlled conditions: 2 with pasteurized milk using a mesophilic lactic acid bacteria culture (Lactococcus lactis ssp. lactis and L. lactis ssp. cremoris) and a thermophilic lactic acid bacteria culture (Streptococcus salivarius ssp. thermophilus), and a third with naturally acidified raw milk. The cheeses were evaluated by a panel of 11 trained judges. Additionally, chemical composition and instrumental color parameters were determined, an instrumental texture profile analysis was performed, and volatile compounds were identified by solid-phase microextraction coupled with gas chromatography/mass spectrometry. The sensory profile developed includes 43 descriptors, of which 13 are discriminant among these 3 cheese types. Descriptors include visual attribute waxy; tactile (manual) attributes moist and oily; orthonasal aroma attributes empyreumatic and cow; basic taste attribute salty; mouth texture attributes chewable, gummy, adherent, fibrous, moist, and fatty; and auditory attribute squeaky. A strong correlation was found between specific sensory data and physicochemical parameters measured by instrumental and chemical methods.

PCR-DGGE for the profiling of cheese bacterial communities: strengths and weaknesses of a poorly explored combined approach

Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) represents a still valid molecular tool for the profiling of complex microbial ecosystems, including cheeses. In the present study, a double PCR-DGGE approach has been applied to the investigation of the bacterial diversity of seven cheese models to objectively assess strengths and weaknesses of such an approach. To that end, the bacterial DNA was extracted directly from both the cheese replicates and the bulks of colonies harvested from the serial dilution agar plates of selective solid media used for the enumeration of presumptive lactobacilli, lactococci and thermophilic cocci, respectively. The results overall collected allowed the main bacterial taxa to be identified and roughly quantified. Rough quantification of the main cultivable species represents a strength of the PCR-DGGE approach applied, whereas its main weaknesses were represented by the low degree of selectivity of the conventional growth media used for cultivation of lactic acid bacteria and the underestimation of the effective microbial diversity occurring in the seven cheese models.

A large factory-scale application of selected autochthonous lactic acid bacteria for PDO Pecorino Siciliano cheese production

The main hypothesis of this study was that the autochthonous lactic acid bacteria (LAB) selected for their dairy traits are able to stabilize the production of PDO (Protected Denomination of Origin) Pecorino Siciliano cheese, preserving its typicality. The experimental plan included the application of a multi-strain lactic acid bacteria (LAB) culture, composed of starter (Lactococcus lactis subsp. lactis CAG4 and CAG37) and non starter (Enterococcus faecalis PSL71, Lactococcus garviae PSL67 and Streptococcus macedonicus PSL72) strains, during the traditional production of cheese at large scale level in six factories located in different areas of Sicily. The cheese making processes were followed from milk to ripened cheeses and the effects of the added LAB were evaluated on the microbiological, chemico-physical and sensorial characteristics of the final products. Results highlighted a high variability for all investigated parameters and the dominance of LAB cocci in bulk milk samples. The experimental curds showed a faster pH drop than control curds and the levels of LAB estimated in 5-month ripened experimental cheeses (7.59 and 7.27 Log CFU/g for rods and cocci, respectively) were higher than those of control cheeses (7.02 and 6.61 Log CFU/g for rods and cocci, respectively). The comparison of the bacterial isolates by randomly amplified polymorphic DNA (RAPD)-PCR evidenced the dominance of the added starter lactococci over native milk and vat LAB, while the added non starter LAB were found at almost the same levels of the indigenous strains. The sensory evaluation showed that the mixed LAB culture did not influence the majority of the sensory attributes of the cheeses and that each factory produced cheeses with unique characteristics. Finally, the multivariate statistical analysis based on all parameters evaluated on the ripened cheeses showed the dissimilarities and the relationships among cheeses. Thus, the main hypothesis of the work was accepted since the quality parameters of the final cheeses were stabilized, but all cheeses maintained their local typicality.

Opportunities and limitations for the production of safe fermented meats without nitrate and nitrite using an antibacterial Staphylococcus sciuri starter culture

The ability of the meat isolate Staphylococcus sciuri I20-1 to inhibit food-borne pathogens in view of its application as a functional starter culture for the production of clean-label fermented meats was investigated. The strain produced a heat-stable antibacterial compound of a proteinaceous nature that was released following primary metabolite production kinetics. Its specific inhibitory spectrum included different strains of Staphylococcus aureus and both vegetative cells and spores of Clostridium botulinum. These two species pose potential biosafety hazards, in particular when producing fermented meats with a mild pH and without added nitrate and nitrite salts. Up till now, starter-culture based strategies to restrain S. aureus and C. botulinum have barely been explored in fermented meats, in contrast to the frequently investigated use of antilisterial cultures of lactic acid bacteria. When added to a fermented sausage model, S. sciuri I20-1 acted as a persistent culture throughout the fermentation process, during which it was able to produce its antibacterial compound in situ. In co-culture experiments, an immediate two-log inactivation of a S. aureus strain was found, even before production of the antibacterial compound could be detected. This was probably due to an instant pH-driven desorption of the antibacterial molecules from the producer cells when added to the meat batter. However, a sub-population of S. aureus that was resistant to the antibacterial compound was able to grow out to the same final counts as in the control experiment performed with a non-inhibitory strain of S. sciuri. This finding is indicative of the potential pitfalls when extrapolating promising in vitro results to the true complexity of fermented food matrices.

Characterization of the anti-inflammatory Lactobacillus reuteri BM36301 and its probiotic benefits on aged mice.

BackgroundThe gut microbiota is playing more important roles in host immune regulation than was initially expected. Since many benefits of microbes are highly strain-specific and their mechanistic details remain largely elusive, further identification of new probiotic bacteria with immunoregulatory potentials is of great interest.ResultsWe have screened our collection of probiotic lactic acid bacteria (LAB) for their efficacy in modulating host immune response. Some LAB are characterized by suppression of TNF-α induction when LAB culture supernatants are added to THP-1 cells, demonstrating the LAB’s anti-inflammatory potential. These suppressive materials were not inactivated by heat or trypsin. On the other hand, treatment of THP-1 directly with live bacterial cells identified a group of pro-inflammatory LAB, which stimulated significant production of TNF-α. Among those, we chose the Lactobacillus reuteri BM36301 as an anti-inflammatory strain and the L. reuteri BM36304 as a pro-inflammatory strain, and further studied their in vivo effects. We supplied C57BL/6 mice with these bacteria in drinking water while feeding them a standard diet for 20 weeks. Interestingly, these L. reuteri strains evoked different consequences depending on the gender of the mice. That is, males treated with anti-inflammatory BM36301 experienced less weight gain and higher testosterone level; females treated with BM36301 maintained lower serum TNF-α as well as healthy skin with active folliculogenesis and hair growth. Furthermore, while males treated with pro-inflammatory BM36304 developed higher serum levels of TNF-α and insulin, in contrast females did not experience such effects from this bacteria strain.ConclusionThe L. reuteri BM36301 was selected as an anti-inflammatory strain in vitro. It helped mice maintain healthy conditions as they aged. These findings propose the L. reuteri BM36301 as a potential probiotic strain to improve various aspects of aging issues.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0686-7) contains supplementary material, which is available to authorized users.

Study on shelf life of Lactic Acid Bacteria inoculated vacuum packed Tenualosa ilisha (Hamilton, 1822) at 5oC.

Lactobacillus pentosus FPTLB13 was used as a biopreservative agent for hilsa steaks ( Tenualosa ilisha ) in vacuum packs at 5OC. The inoculated steaks (T) exhibited lowering of pH from 6.2 to 5.6 on day 12, probably due to production of organic acids. A sharp increase in total volatile base nitrogen was seen after day 12 of storage in treated steaks which could be attributed to extended lag phase of the spoilage microorganisms as result of competitive inhibition by lactic acid bacteria (LAB) and effect of acidification. Application of LAB cultures seems to have decreased the rate of trimethylamine formation (p 0.05) the texture and flavour of hilsa steaks, although the scores of overall acceptability suggests a significant improvement (p<0.05). The inoculated steaks were found to have a shelf life of 12 days under vacuum at 5OC.

Real-time metabolomic analysis of lactic acid bacteria as monitored by in vitro NMR and chemometrics

Lactic acid bacteria (LAB) play an important role in the food industry as starter cultures to manufacture fermented food, and as probiotics. In recent years, there has been an increasing interest in using LAB cultures for biopreservation of food products. It is therefore of great interest to study the detailed metabolism of these bacteria. This study aimed at developing an efficient analytical protocol for real-time in vitro NMR measurements of LAB fermentations, from sample preparation, over data acquisition and preprocessing, to the extraction of the kinetic metabolic profiles. The developed analytical protocol is applied to an experimental design with two LAB strains (Lactobacillus rhamnosus DSM 20021 and Lactobacillus plantarum subsp. plantarum DSM 20174), two initial pH levels (pHi 6.5 and 5.5), two levels of glucose concentration (2.5 and 0.25 g/l), and two batch fermentation replicates. The design factors proved to be strongly significant and led to interesting biological information. The protocol allowed for detailed real-time kinetic analysis of 11 major metabolites involved in the glycolysis, pyruvate catabolism, amino acid catabolism and cell energy metabolism. New biological knowledge was obtained about the different patterns of glutamine and aspartic acid consumption by the two strains. It was observed that L. plantarum consumes more glutamine at low pH (pH 5.5) whereas the opposite applies to L. rhamnosus. Regarding aspartic acid, both of the strains consume it higher at low pH, and overall L. plantarum consumes it more. L. rhamnosus did not consume aspartic acid at pH 6.5. The developed analytical protocol for real-time in vitro NMR measurements of bacterial metabolism allows a relatively easy investigation of different fermentation factors such as new strains, new substrates, cohabitations, temperature, and pH and has a great potential in biopreservation studies to discover new efficient bioprotective cultures.

Binding and detoxification of chlorpyrifos by lactic acid bacteria on rice straw silage fermentation

ABSTRACTThis investigation examined the reduction of pesticide residues on straw inoculated with lactic acid bacteria (LAB) during ensiling. Lactobacillus casei WYS3 was isolated from rice straw that contained pesticide residues. Non-sterilized rice straw, which was inoculated with L. casei WYS3, showed increased removal of chlorpyrifos after ensiling, compared with rice straw that was not inoculated with L. casei WYS3 or sterilized rice straw. In pure culture, these strains can bind chlorpyrifos as indicated by high-performance liquid chromatography analysis. Viable L. casei WYS3 was shown to bind 33.3–42% of exogenously added chlorpyrifos. These results are similar to those of acid-treated cells but less than those of heat-treated cells, which were found to bind 32.0% and 77.2% of the added chlorpyrifos respectively. Furthermore, gas chromatography–mass spectrometry analysis determined that L. casei WYS3 detoxified chlorpyrifos via P-O-C cleavage. Real-time polymerized chain reaction analysis determined that organophosphorus hydrolase gene expression tripled after the addition of chlorpyrifos to LAB cultures, compared with the control group (without chlorpyrifos). This paper highlights the potential use of LAB starter cultures for the detoxification and removal of chlorpyrifos residues in the environment.