Higher Lactic Acid Bacteria Counts Research Articles

Formulation and development of composite fruit peel powder incorporated fat and sugar-free probiotic set yogurt

Reduction of milk fat and added sugar makes the yogurt even healthier, yet texture deformations and less consumer acceptability will be attributed. Fiber incorporation may be counteracting these problems, which is tested in the present study by incorporating underutilize and cheap fiber sources. Composite fruit peel powder (FPP) formulated from industrial waste was incorporated into fat and added sugar-free set yogurts in three different proportions as 0.5%, 0.7% and 1% (w/v). Yogurt without added FPP was considered as the control. Alteration of titrable acidity, pH and lactic acid bacteria viability were evaluated over a period of a month. Total soluble solids content (TSS), color values, texture profile, and consumer acceptability also were tested. Results showed that FPP incorporation reduces the initial pH of the yogurt mix while increasing the TSS and impart color changes. The elevated amount of FPP mixture (0.7% and 1%) adversely affect texture parameters, microbial count and sensory acceptability. Firmness increased, syneresis decreased, and comparatively high lactic acid bacteria counts observed in fat and sugar-free yogurt with 0.5% FPP incorporation. No significant difference (p

Antioxidant Activities of Exopolysaccharides Produced by Lactic Acid Bacteria Isolated from Commercial Yoghurt Samples

An antioxidant is a substance that inhibits the oxidation of other molecules caused by free radicals. The inbuilt antioxidant systems possessed by living organisms are generally not enough to prevent them from oxidative damages and the uses of synthetic antioxidants also have some harmful effects. This study was aimed at evaluating the antioxidant activities of exopolysaccharides produced by lactic acid bacteria isolated from yoghurt. Lactic acid bacteria (LAB) were isolated from six different brands of commercially available yoghurt using deMan Rogosa Sharpe (MRS) agar. The LAB isolates were identified based on morphological and biochemical analyses and were screened for exopolysaccharide (EPS) production. The LAB isolates screened positive were used for EPS production in a liquid medium and the EPS produced were purified and quantified using standard methods. Antioxidant activities of the EPS were evaluated by determining the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ferric ion reducing power, and total phenolic contents. Data obtained were analysed using Analysis of Variance. Total lactic acid bacterial count obtained from the yoghurt samples ranged from 0 - 3.9 × 104 CFU/mL with sample A (Fan Yoghurt) having the highest LAB count (3.9 × 104 CFU/mL). The isolated LAB and their incidence rate were Lactobacillus plantarum (25.49%), L. delbrueckii (19.61%), L. fermentum (15.69%), L. acidophilus (13.73%), Leuconostoc mesenteroides (11.76%), Lactococcus lactis (7.84%), and Lactobacillus casei (5.88%). Fifty-one out of the 64 LAB isolates were screened positive for EPS production and only six were able to produce substantial quantity of EPS ranging from 127.4 - 208.5 mg/L. The exopolysaccharides produced by L. fermentum had the highest DPPH radical scavenging activity (62.90%) while that of L. plantarum had the lowest (23.10%) at a concentration of 1000 μg/mL. Also, the EPS produced by L. fermentum recorded the highest ferric ion reducing power (12.89 mg AAE/mL) at 1000 μg/mL while that of L. plantarum had the lowest (5.62 mg AAE/mL). At 1000 μg/mL, the total phenolic contents of the EPS samples ranged from 1.41 - 1.58 mg GAE/mL, and the EPS produced by L. fermentum had the highest (1.58 mg GAE/mL) while those produced by L. paracasei had the lowest (1.41 mg GAE/mL). This study revealed that the exopolysaccharides produced by the LAB isolates showed high antioxidant activities with respect to their DPPH free radical scavenging activity, ferric ion reducing power and total phenolic contents.

Development of grilled fish paste by sequential anchovies and chili fermentation method

Traditional fermentation of anchovies without the use of starter culture takes up to a year, or more. Under controlled condition, the duration can be shortened and the flavour production can be increased. The objective of this research is to study the effect of adding starter culture with the addition of tomato juice broth on sequential fermentation of anchovies and chili on flavour attributes of grilled fish paste. Fermentation of anchovies were carried out by inoculating 10% (v/v) starter culture in 300 ml 17% salt solution containing 100 g of dried anchovies, with or without the addition of 5% the tomato broth. Both fermentation was carried out at 25 °C for 4 weeks. Total nitrogen, lactic acid bacteria count, soluble protein and pH were determined at day 0, 7, 14, 21 and 28 of fermentation whereas for titrable acidity analysis was conducted at day 0 and 28. The research was continued with the fermentation of chilies. The composition of the formulation contained 77% (w/w) red or green chili, 10% (w/w) fermented anchovies, 7% (w/w) salt and 6% (w/w) garlic. The blended mixture was incubated at 25 °C for 2 weeks. For fermentation of anchovies, higher lactic acid bacteria counts, organic acid and soluble protein were produced when tomato juice broth was added. The fermentation of red chili using fermented anchovies in the presence of tomato broth also produced higher bacterial count and crude protein. Sensory evaluation of grilled fish paste indicated that the red chili inoculated with fermented anchovies with tomato juice broth was the most preferred ingredient. The sequential fermentation of anchovies and chili with the presence of tomato juice broth produced higher organic and amino acids which contributed to the preference of the formulated grilled fish paste.

Potential of quinoa in the development of fermented spoonable vegan products

The aim of this work was to study the potential of two quinoa varieties, Pasankalla (PK), and Rosada de Huancayo (RH), in developing fermented spoonable vegan products. The quinoa flours were fermented by a candidate probiotic Lactobacillus plantarum Q823. Then, two experimental products were developed by flavoring fermented PK flours with date (QD) and fermented RH flour with bilberry and banana (QBB). The nutritional composition, storage time, and sensory properties (the check-all-that-apply method) of QD and QBB were assessed in relation to four commercial vegan fermented snack products. The functionality of L. plantarum Q823 fermentation was demonstrated by high viable lactic acid bacteria counts (log cfu −1 9) of QD and QBB during the 28-day storage compared to commercial products (log cfu −1 <1–8.2 ± 0.04) at the time of purchase. The nutritional composition of QD and QBB was equal or superior to commercial products. Consumers (n = 66) regarded quinoa products as “novel”, “healthy”, and “high in fiber”. However, the quinoa products were also characterized to have an unpleasant aftertaste and “sandy” mouthfeel. To conclude, quinoa has potential in fermented spoonable vegan products, as clearly demonstrated by the successful fermentation process and high lactic acid bacteria viable counts required for probiotic products.

Effect of a Synbiotic Mix on Intestinal Structural Changes, and Salmonella Typhimurium and Clostridium Perfringens Colonization in Broiler Chickens.

Simple SummaryIn Mexico, the poultry industry uses antibiotics to improve meat production through increased feed conversion, growth rate promotion, and disease prevention. Nevertheless, due to the negative effects of antibiotic overuse and abuse, alternative strategies are required. Probiotics, Prebiotics, and Synbiotics are used as feed additives to maintain health and performance status in poultry production and have become a common method in preventing various gut diseases, but the mechanisms of how these mixtures promote animal health are still unclear. This work studies whether a Synbiotic, besides modulating the gut microbiota, can modify the intestinal mucosa ultrastructure, and if this modification can promote health conditions without affecting zootechnical parameters in broilers infected with Salmonella Typhimurium and Clostridium perfringens. Our results show that broilers treated with the Synbiotic, whether infected with pathogens or not, had healthier intestinal mucosa. The Synbiotic mix promotes structural changes in the intestinal mucosa, which in turn promotes the capacity to resist intestinal infections caused by S. Typhimurium and C. perfringens in broilers.Synbiotics can prevent gastrointestinal infections in broilers. This work studies the effect of a Synbiotic on broilers. One-day-old male broilers were divided into groups: Control; Synbiotic; Synbiotic + S. Typhimurium; Synbiotic + C. perfringens; Synbiotic + S. Typhimurium + C. perfringens; S. Typhimurium; C. perfringens; and S. Typhimurium + C. perfringens. Histopathological analysis revealed that the Synbiotic promoted longer villi, less deep crypts, and better villi-crypt ratio. Broilers treated with the Synbiotic, infected with pathogens or not, had healthier mucosa. In groups infected with pathogens, the frequency and intensity of histopathologic lesions were lessened often in groups treated with the Synbiotic. The Synbiotic group had higher lactic acid bacteria counts than the Control group on day 39, and the isolation frequency of S. Typhimurium was lower (p < 0.05) in the Synbiotic-treated groups. On day 18, mucosa, villi, villi-crypt ratio, crypt, and feed intake were influenced by Enterobacteriaceae. However, on day 39 (end of the trial), those parameters were influenced by lactic acid bacteria. The Synbiotic influenced morphological modifications in the duodenal mucosa, which in turn gave the broilers the ability to resist infections caused by S. Typhimurium and C. perfringens, by inhibiting their growth and decreasing the intensity and frequency of histopathological injuries.

Lactic Acid Bacteria Mixture as Inoculants on Low Moisture Italian Ryegrass Silage Fermentation

The effects of lactic acid bacteria (LAB) mixtures on low moisture Italian ryegrass (IRG) silage fermentation was evaluated in field conditions. The experiment was categorized into two groups: Un-inoculated (Control) and Inoculated with LAB mixture for four storage periods (45, 90, 180, and 365 days, respectively). Silage inoculated with the LAB mixture had the lowest pH with highest lactic acid production than the control from beginning at 45-365 days at all moistures. Higher LAB counts were observed in inoculated silages than the control silages at whole experimental periods. It is a key reason for the rapid acidification and higher lactic acid production in silages during the storage periods. Overall results suggest that an adding of LAB mixture had positive effects on the increasing aerobic stability of silage and preserved its quality for an extended duration.

Probiotication of cooked sausages employing agroindustrial coproducts as prebiotic co‐encapsulant in ionotropic alginate–pectin gels

SummaryCooked sausages were formulated inoculating alginate–pectin microcapsules containing agroindustrial coproducts, cactus pear peel flour or apple marc flour, seeking to enhance the nutritional value of cooked meat products. The microcapsules increased total moisture (from 66 to 75% in average), but water was not being physically retained since higher expressible moisture values in inoculated samples were observed (20% as compared to 15% in control). Inoculated samples presented higher lactic acid bacteria populations, since in addition to the thermotolerant capacity of the bacteria, encapsulation added a protective barrier for the bacteria to survive. Higher lactic acid bacteria counts were reflected in fewer coliforms in inoculated samples (&lt;0.001 log CFU after 15 days of storage), with no detrimental effect on texture. Natural antioxidants present in agroindustrial coproducts decreased the oxidative rancidity of lipids for storage. The results imply that agroindustrial coproducts are a good alternative to formulate symbiotic functional ingredients that can be employed to improve the nutritional properties of nondairy thermal processed food products, like cooked emulsified meat products.

The intestinal health of silver catfish Rhamdia quelen can be changed by organic acid salts, independent of the chelating minerals

Food additives based on organic acids or their salts promote numerous improvements in zootechnical parameters, digestive enzymatic activities, resistance to diseases and intestinal health. This study aimed to evaluate the influence of calcium and sodium chelated to propionic acid on the digestive enzymes activities, intestinal microbial community and histological alterations in the liver and intestine of the silver catfish Rhamdia quelen. Fish with an initial mean weight of 8.43 ± 0.18 g were divided into a control and four treatments, with 15 fish in each replicate, and fed the following supplemented diets for 60 days, four times per day: unsupplemented control, Ca-propionate 0.25% (Ca0.25%), Ca-propionate 1% (Ca1%), Na-propionate 0.25% (Na0.25%) and Na-propionate 1% (Na1%). At the end of the assay, digestive enzymes activities in the gastrointestinal tract (GIT) was not affected by the chelating mineral, nor by its concentration to propionic acid. On the other hand, the most important digestive enzymes for silver catfish were lipase and acid protease. Regarding the intestinal microbial community, fish fed Ca0.25% showed a lower concentration of total heterotrophic bacteria and a higher lactic acid bacteria count, compared to Na1%-supplemented fish, in addition to the maintenance of cordonal features and liver cholestasis. Fish fed a Ca0.25% or Na0.25% supplemented diet presented the best histomorphometry parameters, such as the greatest width and number of villi, a lower number of eosinophilic infiltrates and the absence of lymphocytic infiltrates. The organic acid propionate chelated to calcium at 0.25% improved the microbial composition and intestinal health of silver catfish, with no effects on the liver, the most important organ for depuration, and could be indicated as a feed additive for silver catfish.

Prevalence and Antimicrobial Properties of Lactic Acid Bacteria in Nigerian Women During the Menstrual Cycle.

The composition of vagina lactic acid bacteria (LAB) differs within the different ethnic group. This study is aimed at determining the prevalence of LAB with their antimicrobial properties in Nigerian women’s vagina during different stages of the menstrual cycle. Microorganisms were isolated from vaginal swabs of ten Nigerian women during different stages of the menstrual cycle and identified by partial sequencing of the 16S rRNA gene. The antimicrobial properties of the LAB were tested against the multidrug-resistant uropathogens. The prevalence of LAB was higher during ovulation period while during menstruation period, it declined. Twenty-five LAB isolates were identified as three species, namely: Lactobacillus plantarum (15), Lactobacillus fermentum (9), Lactobacillus brevis (1) and one acetic acid bacteria – Acetobacter pasteurianus. The LAB had antimicrobial activities against the three uropathogens with zones of inhibition from 8 to 22 mm. The presence of LAB inhibits the growth of Staphylococcus sp. GF01 also in the co-culture. High LAB counts were found during ovulation period with L. plantarum as a dominant species while during menstruation, there was a decrease in the LAB counts. The isolated LAB has antimicrobial properties against the urogenital pathogens tested thus exhibiting their potential protective role against uropathogens.

Changes in microbial population and chemical composition of corn stover during field exposure and effects on silage fermentation and in vitro digestibility.

ObjectiveTo effectively use corn stover resources as animal feed, the changes in microbial population and chemical composition of corn stover during field exposure, and their silage fermentation and in vitro digestibility were studied.MethodsCorn cultivars (Jintian, Jinnuo, and Xianyu) stovers from 4 random sections of the field were harvested at the preliminary dough stage of maturity on September 2, 2015. The corn stover exposed in the field for 0, 7, 15, 30, 60, 90, and 180 d, and their silages at 60 d of ensiling were used for the analysis of microbial population, chemical composition, fermentation quality, and in vitro digestibility. Data were analyzed with a completely randomized 3×6 [corn stover cultivar (C)×exposure d (D)] factorial treatment design. Analysis of variance was performed using SAS ver. 9.0 software (SAS Institute Inc., Cary, NC, USA).ResultsAerobic bacteria were dominant population in fresh corn stover. After ensiling, the lactic acid bacteria (LAB) became the dominant bacteria, while other microbes decreased or dropped below the detection level. The crude protein (CP) and water-soluble carbohydrate (WSC) for fresh stover were 6.74% to 9.51% and 11.75% to 13.21% on a dry matter basis, respectively. After exposure, the CP and WSC contents decreased greatly. Fresh stover had a relatively low dry matter while high WSC content and LAB counts, producing silage of good quality, but the dry stover did not. Silage fermentation inhibited nutrient loss and improved the fermentation quality and in vitro digestibility.ConclusionThe results confirm that fresh corn stover has good ensiling characteristics and that it can produce silage of good quality.

Effects of storage temperature and combined microbial inoculants on fermentation end products and microbial populations of Italian ryegrass (Lolium multiflorum Lam.) silage.

To examine five lactic acid bacteria (LAB) strains (LCG9, LTG7, I5, TG1 and LI3) isolated from the Tibetan Plateau, and evaluate their combined effects on the silage quality of Italian ryegrass (Lolium multiflorum Lam.) at three temperatures (10, 15 and 25°C). The isolated strains were evaluated by morphological, physiological and biochemical tests. Six combined inoculants LCG9+LI3, LCG9+I5, LCG9+TG1, LTG7+LI3, LTG7+I5 and LTG7+TG1 were added to Italian ryegrass for ensiling 30days in laboratory silos (1L) at various temperatures, respectively. All the isolates could grow normally at 5-20°C, pH 3·5-7·0 and NaCl (3·0, 6·5%). Compared to three corresponding controls, all the inoculants improved the silage quality of Italian ryegrass at different temperatures, indicated by markedly (P<0·05) higher lactic acid (LA) contents and ratios of lactic acid/acetic acid (LA/AA), and lower pH and ammonia nitrogen (NH3 -N) contents and undesirable micro-organism counts. At 10°C, LTG7+LI3, I5 or TG1 inoculants performed superior to LCG9+LI3, I5 or TG1 inoculants, evidenced by distinctly (P<0·05) higher LA contents and ratios of LA/AA, and lower pH and NH3 -N contents. LTG7+LI3 or TG1 silages had obviously (P<0·05) higher LAB counts than LTG7+I5 silage at 10°C. Therefore, the combined inoculants LTG7+LI3 or TG1 are recommended as starter cultures for Italian ryegrass silage at low temperatures. Temperature is a key factor affecting ensilage. In cold regions, low temperature could be an adverse environmental condition during ensiling. However, few studies have focused on improving silage quality at low temperatures. Moreover, analysis of effects of combined LAB strains with their physiological and biochemical characteristics help us use combined LAB inoculants to realize the fermentation optimization.

Impact inoculum dosage of lactic acid bacteria on oat and wheat silage fermentation at ambient and low temperatures

Lactic acid bacteria (LAB) can be used as silage additives to ensure rapid and vigorous fermentation at early stages of ensiling. We predicted that the optimal LAB inoculation dosage for forage at ambient temperature (15–38°C) would be different from that at cold temperature (4°C). In this study, Lactobacillus plantarum QZ227, isolated from a wheat landrace in alpine regions of Qinghai, China, and commercial L. plantarum FG1 were used as inoculum, with sterile water as control. The effects of inoculum dosage on the fermentation quality of oat (Avena sativa L. cv. Qinghai) and wheat (Triticum aestivum L. cv. Yumai No. 1) silage at ambient temperature (15–38°C) and at 4°C were investigated in laboratory experiments. Little or no improvement in silage quality occurred upon increasing the inoculum dosage at ambient temperature. By contrast, a lower pH and NH3-N content, and a higher LAB count and lactic acid content, were observed at 4°C. Furthermore, the growth of Escherichia coli was inhibited effectively at the lower temperature, and silage quality was positively correlated with increasing inoculum dosage (P&amp;lt;0.05). These results suggest that increasing the inoculum dosage could improve the quality of silage at lower temperatures of 4°C, whereas an appropriate dosage was a key factor for silage at ambient temperature. In this study, oat forage could be used as raw materials for ensiling only at low temperature but was not suitable for ensiling at ambient temperature without wilting due to the high moisture content (86.55%). QZ227 isolated from the roots of wheat in alpine regions displayed superior antimicrobial properties against yeast at ambient temperature and E. coli at 4°C compared with commercial strain FG1. This is the first study to explore the effects of inoculum dosage on silage quality at low temperatures, and provides a basis for low-temperature silage technologies.

Chemical and sensory characteristics of frozen wheygurt with the addition of taro and lesser yam flours as thickening agent

Cheese whey is a waste product from cheese processing. It has low solid contents thus required the addition of a thickening agent. Lactic acid bacteria could utilize it in the fermented drink. This research aims to study the effect of taro and lesser yam flour addition as a thickening agent on chemical and sensory characteristics of frozen wheygurt. This research used Complete Randomized Design (CRD) with one factor that is variation ratio of taro and lesser yam flour F1 (4: 0), F2 (3: 1), F3 (2: 2), F4 (1: 3), F5 (0: 4). The number of lactic acid bacteria cell determined by using hemocytometer. The lactic acid content determined by the titrimetric method by using 0.1 N NaOH and phenolphthalein as indicator. pH value measured with pH meter. Sensory characteristics evaluated using hedonic test. The result showed that the addition of taro and lesser yam flour have a significant effect on the number of lactic acid bacteria in frozen wheygurt. The higher lesser yam flour addition, the higher lactic acid bacteria count on frozen wheygurt, due to lesser yam higher glucose and fructo-oligosaccharide content than taro. The higher lesser yam addition, the higher the lactic acid produced. The higher the total bacteria and higher levels of lactic acid, the lower the pH obtained. The conclusion of this study is addition ratio of taro and lesser yam flour effect on the chemical characteristics of frozen wheygurt. There is no difference in the level of acceptance of the panelists in sensory evaluation.

Citrus Peel Oils Supplementation in Broiler Diet: Effects on Performance, Jejunum Microflora and Jejunum Morphology

ABStRACt This study was carried out to determine citrus peel oils (orange, lemon, bergamot) as food supplementation in different levels on performance, microflora and morphology in broilers. The trial consisted of 1-day-old male and female Ross 308 chicks (250 male 250 female). The study consisted of 10 groups in total and each group was replicated five times. Experimental diets were prepared by adding orange, lemon and bergamot peel oil levels (1,2 and 3 mL/kg) to basal diet. It was observed that the supplementation of citrus peel oils to the diet improved significantly the feed conversion rate. Especially the lowest feed intake and the best feed conversion ratio were received from broilers which were fed 3 mL/kg of orange peel oil. The study shows that the count of Escherichia coli ( E.coli ) and lactic acid bacteria in the jejunum decreased significantly with the supplementation of bergamot peel oil to broilers diets. Citrus peel oil, in contrast to bergamot peel oil, significantly increased lactic acid bacteria count. The highest lactic acid bacteria count was determined in birds fed 3 mL/kg with orange peel oil. In the result of this study, both the length and density of villi and the density of blood and lymphatic capillary in the jejunum increased significantly by dietary 3 mL/kg orange peel oil supplementation. Finally, our results indicate that, especially 3 mL/kg orange peel oil has positive effects on performance, jejunum microflora, and jejunum morphology. It could be advised to supply broilers feed with 3 mL/kg orange peel oil as feed additives.

Antagonistic and Quantitative Assessment of Indigenous Lactic acid Bacteria in Different Varieties of Ogi against Gastrointestinal Pathogens.

IntroductionOgi is a popular fermented cereal gruel consumed mainly in the western part of Nigeria. Traditionally, uncooked Ogi is normally administered to diarrhoea patients to reduce the frequency of stooling. This study was therefore undertaken to identify, quantify and determine the antimicrobial properties of lactic acid bacteria (LAB) isolated from Ogi.MethodsThe Ogi samples (Yellow, white, sorghum) were obtained from different market in Ibadan, Nigeria and Ogi control (cooked, uncooked and Omidun) were prepared with the viable counts of bacteria monitored over 5 days period. LAB were isolated from the varieties and identified by partial sequencing of 16S rRNA gene. The antimicrobial activities of the cell free supernatant (CFS) and the viable cells of the isolated LAB against Escherichia coli EC004, Salmonella sp. SS11, Shigella sp. SS10 were investigated by agar diffusion assay, agar overlay method, and coculture growth studies.ResultsOmidun had the highest LAB count while cooked ogi has the lowest LAB count. Weissella paramesenteroides , L. brevis, L. rossiae, L. fermentum, L. plantarum, Acetobacter pasteurianus, Paenibacillus sp. and Bacillus sp. were isolated from Ogi in this study. Large zone of inhibition (11≤x≤20) was observed with CFS against Salmonella sp. SS11 and Shigella sp. SS10 and also the overlay method. Coculture studies of Weissella paramesenteroides, Lactobacillus fermentum, and L. plantarum with Salmonella sp. SS11 showed a 5-8 log reduction of the pathogens' growth after 24 hours as compared with the control.ConclusionOgi and its contents have antimicrobial properties against pathogenic organisms.

PREVALENCE OF LACTIC ACID BACTERIA IN SLICED COOKED HAM AS AN INDICATOR OF ITS SHELF LIFE

Background: Ready to eat sliced-cooked-meat-products (RTE) are popular convenience foods. Slicing of such products at retail point is a common practice in supermarkets. Due to handling, as well as the supermarket environment, it has been suggested that the counts and presence of specific lactic acid bacteria (LAB) in these products may be associated with their rapid deterioration and short shelf life. Objectives: The aim was to quantify and identify LAB in commercial sliced cooked ham. Methods: Thirty samples of sliced cooked ham were collected from five supermarkets. Each sample was analyzed in terms of: Lactobacillus on De Man Rogosa, Sharpe agar (30°C), mesophilic (30°C) and thermophilic (37oC ) Streptococcus on M17 agar containing 1% lactose, Lactococcus on LM17 agar containing 100 µg per liter of cycloheximide (25°C) and Enterococci on Kanamicin Aesculin Azide agar containing kanamycin (37°C), all under anaerobic conditions (Gas-Pack System®, BBL) for 48-72h. Twenty-one colonies were randomly picked and physiologically and biochemically characterized. Results: No difference was observed in genuses between supermarkets; however, significant differences were observed between microbial genuses. Enterococci showed the lowest count (2.34 ± 0.05 log10 CFU/g) and Lactobacilli had the highest counts (5.98 ± 0.04 log10 CFU/g). Of the strains isolated 23.8% were identified as thermophillic Lactobacillus, 23.8% mesophilic Lactobacillus, 28.6% Enterococcus, 14.3% Lactococcus and 9.5% Streptococcus. From these, only six could be characterized to species level; one was L.lactis subsp. lactis and five were L. amylolyticus. Conclusions: High LAB counts are a common cause of spoilage in RTE meat products, since these are commonly found in meat environments. Therefore a study on the processing, distribution and in-site handling of RTE meat products at supermarkets may be necessary in order to increase its shelf life.

Lactic acid bacteria used as preservative in fresh feed for marine shrimp maturation

Abstract The objective of this work was to evaluate the effect of Lactobacillus plantarum on the preservation of fresh mussels and its effect on the attractiveness, consumption, and midgut bacterial microbiota of Pacific white shrimp broodstock. The experiment evaluated mussels stored with L. plantarum at 4ºC. The controls were: mussels stored at -18ºC without L. plantarum; mussels stored at -18ºC with L. plantarum; and mussels stored at 4ºC without L. plantarum. Microbiological analyses on mussels were performed on days 1, 7, 15, 30, 45, and 60 after processing. Additionally, mussels preserved with L. plantarum and stored at 4ºC, and mussels stored at -18ºC without L. plantarum were evaluated after 15 days for attractiveness, consumption, and midgut bacterial microbiota of shrimps. Mussels preserved with L. plantarum showed higher lactic acid bacteria counts and lower counts of Vibrio spp., as well as of total heterotrophic bacteria, after 60 days of storage. No differences were observed for attractiveness or consumption between treatments. The bacterial microbiota of midgut in shrimp fed mussels preserved with L. plantarum showed higher lactic acid bacteria count and lower Vibrio spp. The use of L. plantarum inhibits Vibrio spp. and preserves feed without changing attractiveness or consumption for shrimp.

Impact of NaCl reduction in Danish semi-hard Samsoe cheeses on proliferation and autolysis of DL-starter cultures

Reduction of sodium chloride (NaCl) in cheese manufacturing is a challenge for the dairy industry. NaCl has a profound role on microbial development influencing cheese sensory and technological properties. The purpose of this work was to investigate how proliferation, distribution and autolysis of two commercial DL-starter cultures (C1 and C2) used in the production of Danish semi-hard Samsoe cheeses were affected by reduced NaCl levels. Cheeses containing <0.3% (unsalted), 2.3% (reduced-salt) and 3.4% (normal-salted) (w/v) NaCl in moisture were produced and analyzed during 12weeks of ripening. Lactic acid bacteria (LAB), distribution of bacteria as single cells or microcolonies, their viability in the cheeses and cell autolysis were monitored during ripening, as well as the impact of NaCl content and autolysis on the formation of free amino acids (FAA).Reduction of NaCl resulted in higher LAB counts at the early stages of ripening, with differences between the two DL-starter cultures. The unsalted cheeses produced with C1 had retained a significantly higher number of the initial LAB counts (cfu/g) after 1 and 2weeks of ripening (i.e. 58% and 71%), compared to the normal-salted cheeses (i.e. 22% and 21%), whereas no significant difference was found between the reduced-salt (i.e. 31% and 35%) and normal-salted cheeses. At the later stages of ripening (i.e. 7 and 11weeks) NaCl had no significant influence. For cheeses produced with C2, a significant influence of NaCl was only found in cheeses ripened for 7weeks, where the unsalted and reduced-salt cheeses had retained a significantly higher number of the initial LAB counts (cfu/g) (i.e. 39% and 38%), compared to the normal-salted cheeses (i.e. 21%). In the Samsoe cheeses, bacteria were organized as single cells, in groups of 2–3 cells or in groups of ≥4 cells. During ripening the decrease in the number of viable bacteria was mainly due to a reduction in the number of viable bacteria organized in groups of ≥4 cells. A negative correlation between NaCl content and PepX activity was observed. At the end of ripening the total FAA content was lower in the unsalted cheeses, compared to the reduced- and normal-salted cheeses.In conclusion, NaCl had a significant influence on proliferation of both DL-starter cultures. However, the influence of NaCl on culture development was more pronounced in cheeses produced with DL-starter culture C1. As both texture and taste are parameters known to be affected by the development of the starter culture, the design of starter cultures for reduced NaCl cheeses is recommended.

Replacement of aruana grass by gliricidia (Gliricidia sepium) on silage quality

Our objective was to investigate the effect of the replacement of aruana grass by gliricidia on the fermentative losses, chemical composition, and aerobic stability of silages. For ensiling, whole-crop aruana grass (75 d of growth) was chopped (275 g kg-1 dry matter - DM) and ensiled alone or associated with gliricidia (270 g kg-1 DM; 150 d of growth). For gliricidia, we used only the leaves and stalks to ensile. The evaluated treatments were different ratios of aruana grass to gliricidia (100:0, 75:25, 50:50, 25:75, and 0:100), with four replicates (mini-silos). The silage composed only of gliricidia exhibited a lower pH than the other silages. Dry matter recovery was not affected by the treatments, although effluent losses were affected. The replacement of aruana grass by gliricidia 50% at ensiling resulted in a higher lactic acid bacteria count. The aruana grass silages displayed lower protein contents and a higher neutral detergent fiber content than the gliricidia silages after 40 d of fermentation. Consequently, the silage consisting of 100% gliricidia showed higher in vitro DM digestibility, presenting an increase of 8.13% after 40 d of fermentation compared with 100% of aruana grass silage. After silo opening, the gliricidia silage was very stable (>72 h). The low quality of aruana grass silage is improved by replacing this grass with significant amounts of gliricidia (approximately 75%).

Effect of packaging and storage conditions on microbial survival, physicochemical characteristics and colour of non-thermally preserved green Spanish-style Manzanilla olives

This work studies the effect of packaging material (glass jar or plastic pouches), olive environment (covered with brine, under N2 atmosphere or vacuum) and storage temperature (7, 13, and 22 °C) on the microbial survival, brine characteristics and colour of packaged fermented olives (Manzanilla cv.) subjected to preservation only by pH and NaCl levels. The highest lactic acid bacteria counts on olive epidermis (6.2–6.5 log10 CFU/olive) were found in fruits stored in glass jar and plastic pouches at 22 °C which, on the contrary, showed the lowest yeast population levels (5.2–6.5 log10 CFU/olive) due to the opposed growth trend observed between bacteria and yeasts. The pH increase in the packages with brine limited the product shelf life to about 2 months but without brine the shelf life could be longer. Changes in colour parameters did not affect the product's shelf life. The verification of the high lactic acid bacteria on the olive surface, particularly for plastic pouches with brine, and under N2 atmosphere at room temperature, constitutes an essential step for producing probiotic table olives.