Culture Lactobacillus Plantarum Research Articles

Microbial profiles during lactic fermentation of meat by combined starter cultures at high temperatures

Studies were conducted to stabilize minced meat and meat cubes with added salt and glucose by fermentation using mixed lactic cultures of Lactobacillus plantarum, Lactobacillus casei and Lactococci lactis. Microbial profiles were recorded. The study revealed that a desired pH of 4.0–4.2 can be achieved (within 24–36 h at 37 °C and 30–42 h at 30 °C), with a substantial reduction in coliforms, Escherichia coli, Staphylococcus aureus and Salmonella spp. The study demonstrated that the use of combined lactic cultures would enhance the fermentation process and preserve fresh meat for extended periods at high temperatures for further use in the development of specific products.

Effects of pressure-induced membrane phase transitions on inactivation of HorA, an ATP-dependent multidrug resistance transporter, in Lactobacillus plantarum.

The effects of pressure on cultures of Lactobacillus plantarum were characterized by determination of the viability and activity of HorA, an ATP-binding cassette multidrug resistance transporter. Changes in the membrane composition of L. plantarum induced by different growth temperatures were determined. Furthermore, the effect of the growth temperature of a culture on pressure inactivation at 200 MPa was determined. Cells were characterized by plate counts on selective and nonselective agar after pressure treatment, and HorA activity was measured by ethidium bromide efflux. Fourier transform-infrared spectroscopy and Laurdan fluorescence spectroscopy provided information about the thermodynamic phase state of the cytoplasmic membrane during pressure treatment. A pressure-temperature diagram for cell membranes was established. Cells grown at 37 degrees C and pressure treated at 15 degrees C lost >99% of HorA activity and viable cell counts within 36 and 120 min, respectively. The membranes of these cells were in the gel phase region at ambient pressure. In contrast, cells grown at 15 degrees C and pressure treated at 37 degrees C lost >99% of HorA activity and viable cell counts within 4 and 8 min, respectively. The membranes of these cells were in the liquid crystalline phase region at ambient pressure. The kinetic analysis of inactivation of L. plantarum provided further evidence that inactivation of HorA is a crucial step during pressure-induced cell death. Comparison of the biological findings and the membrane state during pressure treatment led to the conclusion that the inactivation of cells and membrane enzymes strongly depends on the thermodynamic properties of the membrane. Pressure treatment of cells with a liquid crystalline membrane at 0.1 MPa resulted in HorA inactivation and cell death more rapid than those of cells with a gel phase membrane at 0.1 MPa.

A biotechnological process for treatment and recycling poultry wastes manure as a feed ingredient

Poultry wastes manure was diluted by adding the same amount of water 50–50 (w/v). They were then mixed with 10% molasses. The mixture was inoculated with a starter culture of Lactobacillus plantarum and Pediococcus acidolactici, and incubated at 30°C for 10 days. Changes in nutritional quality and biochemical properties (pH, total nitrogen, total volatile nitrogen, non protein nitrogen, carbohydrates and ash) were determined for the raw and the transformed product. In parallel, microbiological analyses, including standard plate count, enterobacteria and enterococci, were performed. Results indicated that the product obtained from the wastes fermentation showed low counts of enterobacteria and enterococci. Chemical determinations showed a net decrease of the pH to around 4.0 and the growth curve of the lactic acid bacteria showed the success of the acidification process. The total nitrogen was conserved in the product and the total volatile nitrogen was totally eliminated. The product was used for substituting some protein sources in a conventional formula used in laying feeding of three lots. Two formulae containing, respectively, 20% and 40% of the product were compared to the control (0%). The food consumption and laying performances were monitored for 30 days. The nutritional test indicated that the incorporation of the poultry manure silage at a rate of up to 40% gave laying performances similar to those obtained with the conventional formula. These results show that it is possible to transform poultry manure by controlled fermentation and that the product has an added value as a feed ingredient.

Mechanism ofSalmonella reduction in fermented pig feed

To protect consumers from Salmonella infection acquired through the consumption of pork meat, it is necessary to eradicate Salmonella from pork. In order to achieve this, the whole pork production chain should be free from Salmonella, including the pigs at the farm. In epidemiological studies it was concluded that the use of fermented feed plays a significant role in the reduction of Salmonella prevalence in pig farms. However, the mechanism of Salmonella reduction in fermented feed is not known. A controlled feed fermentation was performed using a pure culture of Lactobacillus plantarum. pH reduction, organic acid profiles and bacterial counts were determined. In L plantarum-fermented feed, lactic acid and acetic acid were produced and the pH dropped to a value below 4.0. Antimicrobial products (bacteriocins) could not be detected. The results showed that the produced lactic and acetic acid and the pH in the feed are responsible for Salmonella reduction in fermented feed. L plantarum did not show any other antimicrobial effect on Salmonella. © 2000 Society of Chemical Industry

Lactic acid fermentation and storage of blanched garlic

The controlled fermentation of peeled, blanched garlic, using a starter culture of Lactobacillus plantarum, was studied and compared with that of unblanched garlic. Blanching was carried out in hot water (90°C) for 15 min. The starter grew abundantly in the case of blanched garlic, producing mainly lactic acid and reaching a pH of 3.8 after 7 days, but its growth was inhibited in unblanched garlic. Ethanol and fructose, coming from enzymatic activities of the garlic, and a green pigment were formed during the fermentation of unblanched garlic, but not of blanched garlic. The blanched garlic fermented by L. plantarum, even without a preservation treatment (pasteurization), was microbiologically stable during storage at 30°C in an acidified brine (∼3% (w/w) NaCl and pH 3.5 at equilibrium), but fructans were hydrolyzed. The packed fermented product and that obtained by direct packing without fermentation were not significantly different with regard to flavour.

Process for recycling slaughterhouses wastes and by-products by fermentation

Slaughterhouse wastes including animal and poultry wastes, were mixed separately with 15% molasses and inoculated with a starter culture of Lactobacillus plantarum. The mixture was incubated at 22–24 °C for 10–15 days. Physico-chemical and chemical determinations including pH, dry matter, ash, Total Nitrogen (TN), Non Protein Nitrogen (NPN), Total Volatile Nitrogen (TVN), lipids and reducing sugars were determined on the products. In parallel, microbiological analyses, including standard plate count, coliforms, Salmonella, Clostridium, were also determined daily. Results indicated that the product obtained from the animal wastes showed low counts of coliforms. Salmonella was not detected. Chemical determinations showed a net decrease of the pH and low levels of total volatile nitrogen with a decrease in total sugars. Non protein nitrogen was high in the product relative to the raw material, while the product obtained from poultry by-products showed very interesting data for both chemical and microbiological characteristics: that is, pH decrease to low levels was rapid and the preservation was ensured by the net decrease in Gram negative bacteria and Clostridium, the absence of Salmonella and the stabilization of the standard plate counts. The product had a high level of fat and crude protein.

Effect of roasting and fermentation on viscosity of cereal-legume based food formulas

With the view of preparing semi-liquid weaning foods of high energy content, the influence of roasting (stationary hot air treatment) and fermentation (with natural and pure culture inocula) on the viscosity of maize-sorghum-soya porridges was investigated. Roasting resulted in porridges of significantly higher viscosity (cooked porridge cooled to 40 degrees C). Porridges made from the individual ingredients (maize, sorghum, soya) did not show this behaviour. Natural fermentation of mixed ingredients resulted in lower porridge viscosities (cooked porridge cooled to 40 degrees C, as well as hot-paste peak viscosity) when pH was 5.0-5.5. At lower pH the viscosity of the final porridges increased. Fermentation experiments of individual ingredients inoculated with pure cultures of Lactobacillus plantarum and Candida famata lead to the conclusion that various factors contribute to the effect of fermentation on porridge viscosity. Porridges of minimum viscosity are obtained at pH 5.0-5.5 corresponding with a moderate extent of fermentation. From a consumer safety point of view, it would be preferable to acidify to lower pH values (pH < 4.5). If necessary, viscosity adjustments could be made using malted cereals.

Effects of gluconodeltalactone and Lactobacillus plantarum on the production of histamine and tyramine in fermented sausages

Fermented sausages were made experimentally with addition of 0.3% (w/w) gluconodeltalactone (GDL) or a starter culture of Lactobacillus plantarum, unable to produce histamine or tyramine. Controls were produced without GDL and starter culture. During 15 days preparation and storage periods, number of bacteria and lactobacilli, pH, and levels of histamine, tyrosine and tyramine were monitored, and organoleptic evaluations were carried out. Maximal histamine levels were 19.41 μg/g of dry matter in the GDL-added sausages, 18.64 μg/g in control, and 17.20 μg/g in the starter sausages. Maximal tyramine levels were 1249.16 μg/g in the GDL sausages, 1101.16 μg/g in the control, and 906.35 μg/g in the starter sausages. Sausages produced with GDL proved less acceptable in organoleptic evaluation due to an unpleasant sour flavour.

Chemical and nutritional quality of stored fermented fish (tilapia) silage

Abstract Fermented fish silage was produced from minced tilapia ( Oreochromis niloticus ), 15% molasses and 5% Lactobacillus plantarum culture. Initially, batches of the fish silages were fermented at 5, 20, 30 or 35°C for 30 days. The pH declined rapidly at 20, 30 and 35°C but at 5°C, pH decline was slower. Protein solubilization (autolysis) in the fish silages was temperature-dependent as the non-protein nitrogen content (NPN) increased rapidly at higher temperatures. In a second experiment, fish silage was fermented at 30°C for 7 days after which autolysis was halted, then stored at 30°C for 180 days and analysed at intervals. The NPN attained a maximum of 51·4% of total nitrogen content after 180 days. Proximate composition of tilapia silages varied slightly during storage and there was a slight loss of tryptophan during fermentation and storage. The stored wet tilapia silages were blended with soybean meal (1:1, w/w) and dried. The nutritional value of co-dried tilapia silage as a dietary protein supplement for catfish ( Clarias gariepinus ) was studied in digestibility experiments. Although the protein quality of wet tilapia silage was reduced during storage, there were no differences ( P > 0·05) in the apparent protein digestibility coefficients of diets containing co-dried tilapia silages. It is suggested that autolysis in the stored tilapia silages had little effect on proten digestibility in the catfish.

Effect of premix ingredients and its inoculation with lactic acid‐producing bacteria on ensiling of poultry droppings with conventional feeds

A premix of poultry droppings (25 parts) and wheat straw (65 parts) was inoculated with a mixed culture of Lactobacillus plantarum and Streptococcus faecalis in the presence or absence of sugarcane molasses. The inclusion of lactic acid‐producing bacteria and molasses in the premix resulted in reduced pH, ammonia nitrogen and total volatile fatty acids and increased production of lactic acid during a fermentation time of 20 d at 32–35°C. The sugarcane molasses and part of the wheat straw can be replaced with green maize fodder in the vegetative stage without any adverse effect on the silage characteristics. With an increasing level of green maize in the premix, there was a decrease in pH, dry matter of premix and wastelage and a significant increase in soluble sugars of premix and titrable acidity and lactic acid content of wastelage. A good wastelage can be produced when the premix consists of poultry droppings, wheat straw and green maize in the ratio of 25: 15:60, respectively, and it is inoculated with lactic acid‐producing bacteria.

Spontaneous and SDS-induced Phenotype and Plasmid Alterations in Starter Cultures of Lactobacillus plantarum

Summary Starter cultures of Lactobacillus plantarum, unable to grow beyond a micro-colony stage on nutritionallydeficient media, spontaneously adapt by forming macro-colony variants after 5–14 days of incubation. Twenty-eight percent of the variants remained stable; some of them with altered ability to utilize various carbohydrates. Eighteen percent of the stable variants showed plasmid changes, but there was no obvious participation of plasmids in the variant formation. Restriction endonuclease analysis indicated that DNA rearrangement had occurred in the variant strain studied. SDS-treatment resulted in approximately half of the population reverting to the micro-colony phenotype. Depending on the cultivation media, high-frequency-spontaneous-mutation (HFSM) in Lactobacillus plantarum showed frequencies up to 10-5 mutants per cells inoculated on a plate.

The influence of Lactobacillus plantarum culture inoculation on the fate of Staphylococcus aureus and Salmonella typhimurium in Montasio cheese

The growth and survival of Staphylococcus aureus and Salmonella typhimurium were investigated during the manufacturing and ripening of raw milk Montasio cheese. Initial inoculated populations in the cheese milk were about 10 5 cfu/ml for S. aureus and 10 6 cfu/ml for S. typhimurium. Samples of curds and cheeses were taken during manufacturing and storage and analysed for pH and microbial populations. S. aureus increased slightly in number during the early period ripening and attained a population of about 10 6 cfu/ml during the remaining period of storage. S. typhimurium decreased during cheesemaking and storage but persisted through 90 days. The addition of the Lactobacillus plantarum culture (0.2% v/v) produced a marked reduction in populations ofthe test strains in 10 days of storage. Enterotoxin A was not detected in Montasio cheese even with a S. aureus population of 1.1 × 10 7 cfu/ml. L. plantarum strains were also tested by the spot method and the associative growth approach for their antagonistic activity against S. aureus and S. typhimurium. The compound excreted by L. plantarum was active only toward S. aureus. Furthermore, its activity was destroyed by protease treatment. These results indicated that while the growth of S. typhimurium is reduced by the acid production, S. aureus inhibition can be ascribed to bacteriocin production.

Effect of Salt on Fermentation of Alfalfa. 2. Treatment with Sodium Chloride, Clostridium butyricum, and Lactic Acid Bacteria

Pure cultures of anaerobic bacteria were grown in KCl- and NaCl-treated media, and NaCl was added to alfalfa (Medicago sativa L.) inoculated with Clostridium butyricum to determine effects of salt on growth of silage bacteria and fermentation of potentially putrefactive alfalfa silage. Pure cultures of Lactobacillus plantarum, Streptococcus faecium, and C. butyricum were grown in media containing 0, 100, 200, 400, 600, or 1200mM NaCl or KCl. Growth of C. butyricum did not occur with 100mM or higher NaCl and 200mM or higher KCl. Growth of the lactic acid bacteria, although slower compared to no added salt, was evident at all added salt concentrations. Freshly cut, fourth-cutting alfalfa (vegetative stage) was well-mixed and treated with 1) no inoculant and no NaCl, 2) C. butyricum and no NaCl, 3) C. butyricum and NaCl (4g NaCl/100g wet forage), 4) C. butyricum and lactic acid bacteria, or 5) C. butyricum, NaCl, and lactic acid bacteria. Total anaerobes, total N, pH, lactic, acetic, and butyric acids, and ammonia N were measured. Salt (NaCl) inhibited growth of Clostridium and, apparently, epiphytic lactic acid bacteria. Sodium chloride alone added to Clostridium-inoculated alfalfa did not result in a well-preserved silage. Inoculation with lactic acid bacteria was more effective than NaCl in contributing to a well-preserved silage.

Manganese as a controlling factor in mixed cultures of Lactobacillus plantarum and enterobacteriaceae

Addition of manganese, at levels of 50 ppm, to a liquid growth medium simulating adverse silage conditions had no effect on the growth or on the fermentation pattern of Enterobacter cloacae and Proteus vulgaris. Yet, the manganese strongly enhanced the growth of Lactobacillus plantarum. Co-cultures of L. plantarum and E. cloacae or P. vulgaris were, by addition of manganese ions, significantly altered in the favour of the former. This finding can be of use in mixed cultures where Enterobacteriaceae act as spoiler microorganisms.

Slaughterhouse by-products preserved by Lactobacillus plantarum fermentation as feed for mink and foxes

Lactic acid fermentation was evaluated as a method to preserve abattoir waste for use in fur animal diets. The method used involved grinding, acidifying to pH 5–5.2 by formic acid and propionic acid, addition of 6% molasses as a carbohydrate source and a starter culture of Lactobacillus plantarum. Fermentation was completed after 2–3 days at 25°C. The final pH of the fermented product was 3.8–4.1. Storage experiments revealed satisfactory stability. The fermented products could be kept for weeks at room temperature (20°C) and for months in a cold room (4°C). The amino acid composition of the 4 types of abattoir waste tested was not significantly changed by fermentation. Digestibility studies with mink revealed slight, but significant ( P < 0.05), effects of fermentation. The digestibility of cystine and threonine was reduced and that of glycine and proline increased. Two types of fermented abattoir waste were investigated in 2 long-term feeding experiments with mink and blue foxes. In the mink trial, diets with 10 or 20% fermented abattoir waste supported normal reproduction, kit mortality and body growth. In one experiment, there was a significant reduction in mink kit body weights with 20%, but not with 10% fermented abattoir waste in the diet. In the fox trial, litter sizes and kit viability tended to improve with 20% fermented abattoir waste, while kit body weights were unaffected. It is concluded that fermentation could be an acceptable process for the preservation of abattoir waste intended for the feeding of fur animals.

Influence of lactic starter inoculation, curd heating and ripening temperature on Staphylococcus aureus behaviour in Manchego cheese

Growth and survival of Staphylococcus aureus were investigated in 52 lots of raw ewe's milk Manchego cheese manufactured and ripened under different conditions. A 5.8-fold reduction in S. aureus counts after 60 days of ripening was obtained by inoculating milk with 1% Streptococcus lactis culture, and a further 2.0-fold reduction could be achieved by adding 0.1% Lactobacillus plantarum culture. Curd heating temperature had a significant effect on S. aureus survival, with counts 4–5 times lower in cheese from 30° C curd than in cheese from curd heated at 36–40° C. Ripening temperature was the parameter with the greatest influence on S. aureus counts, which reached in cheese cured at 10° C or 20° C for 60 days levels 10 and 100 times lower, respectively, than in cheese held at 5° C.

Fermentation of Cucumbers in Anaerobic Tanks

ABSTRACTA procedure was developed and tested for fermentation of cucumbers at low concentrations of NaCl in experimental, anaerobic tanks. The procedure included washing of the cucumbers, use of a buffered cover brine composed of 0.045M calcium acetate, sodium chloride to equilibrate at 2.7% or 4.6%, Lactobacillus plantarum culture, and N2 purging to remove dissolved CO2. The fermentations were predominantly homofermentative, lactic acid accounting for 95% of the cucumber sugars fermented. Firmness retention of the fermented cucumbers during storage for 1 year was improved by heating packaged products to 69°C before storage, but firmness retention was acceptable in un‐heated products.

Cellulosic Crop Wastes Ensiled After Rehydration with Fluid Whey1,2

Cotton gin trash was ensiled at 34°C following rehydration to 70% moisture with either water or fluid cottage cheese whey. Split lots of each rehydrated material were inoculated prior to incubation with pure cultures of Lactobacillus plantarum for comparison. Weekly analyses for the first 4 wk plus one at the 8th wk indicated that whey-rehydrated materials gave characteristics of composition, pH, and organic acids similar to analyses for typical, excellent quality, conventional, green crop silages. Water rehydration produced characteristics typical of lower silage quality. Lactobacillus plantarum inoculation showed no advantage.

Effect of Natural Spices and Oleoresins on Lactobacillus plantarum in the Fermentation of Dry Sausage

ABSTRACTThe effect of natural spices and oleoresins on the fermentation properties of three commercially available starter cultures of Lactobacillus plantarum has been investigated. In liquid medium it was shown that natural spices stimulated growth of the three bacteria and thus enhanced the cultures to ferment glucose and form more lactic acid. When similar oleoresin spices were supplied to the growing bacteria no effect was seen. It was also found that natural spices accelerated the fermentation process in the production of salami dry sausage while the oleoresins showed no effect.

Effects of Additives on Lactic Acid Production and Water Soluble Carbohydrates in Chopped Corn and Alfalfa

The increase in rate of lactic acid production resulting from incorporation of silage additives (three commercial products containing amylase enzyme and bacterial culture) with chopped corn (whole plant, 82kg) was approximately 100% compared to a control, during the first 7 days of fermentation. For chopped alfalfa the increase (14 days fermentation) in rate of lactic acid production ranged between 27 and 69% (four commercial products).Incorporation of a Lactobacillus plantarum culture with chopped whole plant corn (.4kg laboratory silo) increased rate of lactic acid production 70% compared to a control over 48h fermentation. Addition of commercial diastase to chopped corn [whole plant; .4kg (laboratory silo)] that had been treated with sodium metabisulfite to inhibit microbial activity resulted in a higher (33%; 72h incubation) rate of production of water soluble carbohydrates than without the enzyme.