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PubMed1998

Fermentation of soybean flour with Aspergillus usamii improves availabilities of zinc and iron in rats.

Soybean flour was fermented with Aspergillus usamii to improve the availabilities of dietary zinc and iron through the degradation of phytate. Three kinds of experimental diets that differed in protein sources were prepared: one consisting of 40% fermented soybean flour (RS diet), one consisting of 40% fermented soybean flour (FS diet), and one consisting of 20% regular soybean flour and 20% fermented soybean flour (RF diet). Zinc solubilities in the upper and the lower segments of the small intestine were higher in rats fed the FS diet than in rats fed the RS diet. The FS group showed higher solubility of iron in the lower small intestine than the RS group did. Zinc concentrations in the femur and plasma and iron concentrations in the liver and plasma were higher in the FS group than in the RS group. These results suggested that the fermentation of soybean flour improved the availabilities of dietary zinc and iron, which may be induced by increasing the solubilities of these minerals in the small intestine through the reduction of phytate content. Femoral and plasma zinc concentrations in the RF group were higher than in the RS group, but lower than in the FS group. No difference was noted in liver and plasma iron concentrations between the RF group and the FS group. Although phytase activity in FS degrades phytate in the RF diet, higher activity may be needed to degrade phytate completely.

Animals↗
PubMed1976

Protein, methionine, lysine and a fermentation residue as variables in diets of young turkeys.

A study was conducted to determine the effects of adding methionine, lysine and a fermentation residue to practical-type diets containing 24, 27, and 30% protein for young turkeys. A 2 X 2 X 2 X 3 factorial design of variables was used in each of two seven-week experiments. A total of 864 poults were divided into groups such that the 24 diets were each fed to 9 males and 9 females in each experiment. Seven-week body weights were increased 11.4% from 0.1% added DL-methionine and decreased 13.7% from 1.5% added fermentation residue, L-Lysine added at 0.157% failed to increase significantly body weights. Increasing the protein from 24 to 27 and 30% increased seven-week body weights 16.7 and 28.9%, respectively. As dietary protein increased, the increases in body weight from added methionine became smaller, i.e., 16.9, 14.4 and 4.8% in diets containing 24, 27, and 30% protein, respectively. Plots of body weight on (1) amount of methionine and on (2) amount of total sulfur amino acids in the diet show a closer relationship with the latter. The sulfur amino acid requirement of poults to seven weeks of age appears to be at least 1.03%, the highest quantity used in this study. The fermentation residue, a product not currently marketed, remains after the isolation of spectinomycin from controlled fermentation of Streptomyces flavopersicus and contains 14% dry matter. The cause of the depressed growth from the added fermentation residue has been discussed.

Animal Feed↗
PubMed2005

Effects of fermented soy milk on the liver lipids under oxidative stress.

AIM: To investigate the effects of fermented soy milk powder on the antioxidative status and lipid metabolism in the livers of CCl4-injected rats. METHODS: Forty-five healthy male Sprague-Dawley rats were randomly assigned to five groups according to five different diets: control (AIN-76), AIN-76+high-dose fermented soy milk powder, AIN-76+low-dose fermented soy milk powder, AIN-76+high-dose milk yogurt powder and AIN-76+low-dose milk yogurt powder. The experiment lasted for 8 wk. After 4 wk, all the rats received intraperitoneal administration of CCl(4)(0.2 mL/100 g body weight) every week. Total cholesterol (TC), triglyceride (TG), TBARS, ALP, and antioxidative enzymes in the liver were evaluated. RESULTS: There was also no significant difference in TBARS and antioxidative enzymes in the liver. TC and TG in the groups fed with fermented soy milk powder were generally lower than those fed with casein powder. CONCLUSION: Consumption of fermented soy milk was positive in lowering total cholesterol and TG accumulation in the liver under CCl(4)-induced oxidative stress.

Alkaline Phosphatase↗
PubMed1998

Persistence of Escherichia coli O157:H7 in dairy fermentation systems.

We examined (i) the persistence of Escherichia coli O157:H7 as a postpasteurization contaminant in fermented dairy products; (ii) the ability of E. coli O157:H7 strains with and without the general stress regulatory protein, RpoS, to compete with commercial starter cultures in fermentation systems; and (iii) the survival of E. coli O157:H7 in the yogurt production process. In commercial products inoculated with 10(3) CFU/ml, E. coli O157:H7 was recovered for up to 12 days in yogurt (pH 4.0), 28 days in sour cream (pH 4.3), and at levels > 10(2) CFU/ml at 35 days in buttermilk (pH 4.1). For the starter culture competition trials, the relative inhibition of E. coli O157:H7 in the experimental fermentation systems was, in decreasing order, thermophilic culture mixture, Lactobacillus delbrueckii subsp. bulgaricus R110 alone, Lactococcus lactis subsp. lactis D280 alone, Lactococcus lactis subsp. cremoris D62 alone, and Streptococcus thermophilus C90 alone showing the least inhibition. Recovery of the rpoS mutant was lower than recovery of its wild-type parent by 72 h or earlier in the presence of individual starter cultures. No E. coli O157:H7 were recovered after the curd formation step in yogurt manufactured with milk inoculated with 10(5) CFU/ml. Our results show that (i) postprocessing entry of E. coli O157:H7 into fermented dairy products represents a potential health hazard; (ii) commercial starter cultures differ in their ability to reduce E. coli O157:H7 CFU numbers in fermentation systems; and (iii) the RpoS protein appears to most effectively contribute to bacterial survival in the presence of conditions that are moderately lethal to the cell.

Animals↗
PubMed1998

Destruction of Escherichia coli O157:H7 and Salmonella typhimurium in Lebanon bologna by interaction of fermentation pH, heating temperature, and time.

Fermented meats have caused food-borne illness due to enterohemorrhagic Escherichia coli. Consumption of Lebanon bologna was epidemiologically associated wit a recent outbreak of salmonellosis. The present study was conducted to determine the effect of pH (after the fermentation step), final heating temperature, and time on destruction of E. coli O157:H7 and Salmonella typhimurium in Lebanon bologna. Raw Lebanon bologna mix was inoculate with either of the pathogens (ca.10(8) CFR/g and fermented for 12 h at 80 degrees F (26.7 degrees C) and then at 100 degrees F (37.8 degrees C) unit the pH reached wither 5.2 or 4.7. The mix was then heated to 110, 115, or 120 degrees F (43.3, 46.1, or 48.9 degrees C). The bologna was sampled at various times, decimally diluted, and plated on either McConkey sorbitol agar or XLD agar to enumerate E. coli O157:H7 and S. typhimurium, respectively. Fermentation alone reduced populations of both pathogens by < 2 log units and heating alone reduced populations of E. coli O157:H7 by < 3 log units. A combination of fermenting to either pH 5.2 or 4.7, followed by heating at 110 degrees F (43.3 degrees C) for 20h, 115 degrees F (46.1 degrees C) for 10 h, or 120 degrees F (48.9 degrees C) for 3 h reduced populations of both pathogens by > 7 log units. Overall S. typhimurium cells were either equally or significantly less resistant (P < 0.01) than cells of E. coli O157:H7. Significantly interactions (P < 0.01) among the three factors for the destruction of E. coli O157:H7 were observed. A process-specific regression equation was developed to predict the destruction of E. coli O157:H7 in Lebanon bologna.

Colony Count, Microbial↗
PubMed2001

Modeling the survival of Escherichia coli O157:H7 in uncooked, semidry, fermented sausage.

The data collected from studies to monitor inactivation of Escherichia coli O157:H7 in uncooked fermented salami were used to develop models to describe survival of the organism. Three models were developed that included different variables to best describe E. coli O157:H7 reduction. Model A included the variables water activity (a(w)), pH, time, and quadratic variables pH and time. Model B separated the processing stages into fermentation and drying. The fermentation included the variables pH and temperature x time (ttarea) and interaction between the two variables. The drying stage was modeled using the variables time and a(w) and interaction between the two. Model C looked at variables a(w) and the time at pH 5.3 to achieve a 2-D log reduction of E. coli O157:H7 and the interaction between the variables. The variables selected for inclusion in all the models were significant at the P < 0.0001 level. The predicted values for all models correlated well to the observed values with R2 of 0.888, 0.828, 0.836, and 0.818 for models A. Bferm, Bdrying, and C, respectively. The models were validated using data from a trial not used to develop the model. In general the predicted reduction in E. coli O157:H7 count in uncooked fermented salami was greater than for the observed E. coli O157:H7 log reductions for all models, but the relation between the two was linear. The results demonstrate that modeling can be a useful tool in assessing manufacturing practices for uncooked fermented salami processes.

Animals↗
PubMed2002

Viability of Escherichia coli O157:H7 during manufacturing and storage of a fermented, semidry soudjouk-style sausage.

Soudjouk-style batter was inoculated with a five-strain mixture of Escherichia coli O157:H7 at about 7.6 log10 CFU/g in each of two trials. The sticks were fermented and dried at 22 degrees C and 50% relative humidity (RH) for 3 days and then at 9 degrees C and 40% RH for 18 h. After being flattened to about 1.25 cm, the sticks were conditioned at 38 degrees C and 70% RH or at 22 degrees C and 50% RH for about 3 days. After the latter conditioning treatment, sticks either were cooked to an internal temperature of 63 degrees C or received no heat treatment. Final mean pH values after conditioning at 22 degrees C and 50% RH for soudjouk manufactured with a starter culture and dextrose (1.0%) and for soudjouk manufactured without a starter culture were about 4.9 and 6.0, respectively. For soudjouk produced with a starter culture, pathogen numbers were reduced by 4.53 and 0.88 log10 CFU/g after conditioning at 38 degrees C and 70% RH and at 22 degrees C and 50% RH, respectively. For soudjouk produced via natural fermentation, pathogen numbers were reduced by 1.39 and 0.09 log10 CFU/g after conditioning at 38 degrees C and 70% RH and at 22 degrees C and 50% RH, respectively. Cooking reduced pathogen numbers to below the levels detectable by direct plating (<1.0 log10 CFU/g) and by enrichment for soudjouk produced with a starter culture and also reduced pathogen numbers by 6.28 log10 CFU/g for soudjouk produced via natural fermentation. However, cooking also resulted in an unacceptable product. In general, the reduction in pathogen numbers achieved by storage at ambient temperature (25 degrees C) was greater than that achieved by storage at cooler temperatures (4 and 15 degrees C), particularly for soudjouk prepared with a starter culture (for which a final pH value of 4.8 and a 6.4-log10 reduction were obtained after 21 days at 25 degrees C) rather than for that prepared without a starter culture (for which a final pH value of 6.1 and a 2.6-log10 reduction were obtained after 21 days at 25 degrees C). These results indicate that naturally fermented old-country-type sausage may allow the survival of E. coli O157:H7 in the absence of controlled fermentation, postfermentation cooking, and/or an ambient-storage processing step.

Animals↗
PubMed2002

Evaluation of antioxidative and mutagenic properties of 50% ethanolic extract from red beans fermented by Aspergillus oryzae.

Various bean products fermented by microorganisms are commonly consumed in Asian diets; however, the safety or functional properties of fermented beans can vary with different microbial species and with different processes being applied to different beans. The objectives of this study were to evaluate the antioxidative and mutagenic properties of 50% ethanolic extracts from red beans fermented by Aspergillus oryzae. The extracts' antioxidative activities, including alpha,alpha;-diphenyl-beta-picryl-hydrazyl (DPPH) radical-scavenging effects, Fe(2+)-chelating ability, and reducing power, were studied in vitro. The antioxidative effects provided by the extracts depended strongly on their concentrations. In general, antioxidative activity increased with extract concentration to a certain point and then leveled off as the concentration further increased. The fermented red bean extracts showed less of a scavenging effect on the DPPH radical and less reducing power than the commercial antioxidants alpha-tocopherol and butylated hydroxytoluene, but better Fe(2+)-chelating ability. No mutagenicity or toxicity effect on any of the tested strains (Salmonella Typhimurium TA97, TA98, TA100, TA102, and TA1535) was found for the 50% ethanolic extracts of fermented red beans with the Ames mutagenicity assay. These results suggest that the 50% ethanolic extracts were not mutagenic.

Antioxidants↗
PubMed2003

A model study of Escherichia coli O157:H7 survival in fermented dry sausages--influence of inoculum preparation, inoculation procedure, and selected process parameters.

The influence of inoculum preparation, inoculation level, and inoculation procedure on Escherichia coli O157:H7 inactivation during the manufacture of fermented sausage was evaluated in a model study. Prior growth in glucose-enriched tryptone soya broth, which provided exposure to mildly acidic conditions (pH 4.8), had no effect on the later survival of E. coli O157: H7 strains 5-1 and ATCC 43894 under extremely acidic conditions (pH 2), but the same strains became sensitive to acidity after 7 days of incubation on the surface of refrigerated beef (as per the normal contamination route from slaughter to further processing). In subsequent sausage production trials, the extent of destruction observed for E. coli O157:H7 strains F-90, 5-1, and ATCC 43894 inoculated directly into the meat batter was unchanged when the inoculation level was decreased from 7.3 to 4.7 log CFU/g, but the level of inactivation was ca. 1 log higher when the surfaces of beef cuts, rather than the batter, were inoculated 7 days prior to processing. Regardless of processing conditions (fermentation to a pH of < or = 5.0 at 24 or 37 degrees C, drying at 14 degrees C to a water activity [a(w)] value of 0.91 or 0.79), strains F-90, 5-1, and ATCC 43894 showed similar survival capacities during the manufacture of sausage. A approximately 2-log reduction in pathogen numbers was generally obtained after samples were dried to an a(w) of 0.91, irrespective of fermentation temperature. The addition of a 5-day predrying holding stage at the fermentation temperature significantly (P < 0.05) increased pathogen inactivation when fermentation was carried out at 37 degrees C (but not when it was carried out at 24 degrees C). However, significant pathogen reductions (4 to 5 log CFU/g) were achieved only for extensively dried products (a(w) = 0.79).

Animals↗
PubMed2004

Incidence and characterization of Bacillus cereus isolated from traditional fermented meals in Nigeria.

The aim of this study was to examine the presence of Bacillus cereus in fermented meals used in food seasoning in Nigeria. The microbial profiles of iru and ogiri, two Nigerian fermented vegetable proteins, were examined for presence of B. cereus. In the 50 samples tested, B. cereus was detected in all the samples, with the level of detection ranging from log 6.3 to log 8.3 g(-1) sample. Phenotypic characteristics of the B. cereus isolates showed that all of them could not ferment many sugars, most especially mannitol, but they utilized propionate citrate as a source of carbon and grew anaerobically. The isolates do not produce gas from glucose but hydrolyzed starch, casein, and gelatin. API-50CHB combined with API-20E identified the isolates as B. cereus. The diarrheal enterotoxin was detected by a reversed passive latex agglutination test kit. Results showed no significant difference in toxin production between ogiri and iru B. cereus isolated from different sources; all the isolates also demonstrated positive hemolytic activity. The API-ZYM enzyme profile showed that the strains have poor hydrolytic enzyme potential; hence, their possible contributions to the fermentation of vegetable protein is doubtful. This study established the proliferation of B. cereus in fermented protein meal and determined the diarrheal toxin production potential of the organism.

Bacillus cereus↗
PubMed1994

Eurystatins A and B, new prolyl endopeptidase inhibitors. III. Fermentation and controlled biosynthesis of eurystatin analogs by Streptomyces eurythermus.

Accurate and precise component analysis of eurystatin analogs in fermentation broth was devised by HPLC methods with and without 2,4-dinitrophenylhydrazonation. Detailed optimization of fermentation conditions and strain improvement by HPLC analysis significantly increased the eurystatin productivity of Streptomyces eurythermus. Chemically defined fermentation media which produced eurystatins A and B at fermentation yields comparable to complex media were elaborated for radio-isotope fermentation studies and controlled biosynthesis. Radio-isotope incorporation study using 14C-labeled amino acids in chemically defined medium demonstrated that L-leucine and L-ornithine were the direct precursors for the L-leucine and L-ornithine moieties of eurystatins A and B, respectively. Based on this finding, L-valine and L-isoleucine were supplemented to the growing culture of S. eurythermus in chemically defined medium, which resulted in the controlled biosynthesis of new eurystatin analogs named eurystatins C, D, E and F.

Amino Acids↗
PubMed1999

Production of carcinoembryonic antigen (CEA) N-A3 domain in Pichia pastoris by fermentation.

Carcinoembryonic antigen (CEA) is a 180-kDa glycoprotein found on the surface of normal colon and malignant human adenocarcinomas. Recently, a fusion protein containing two of the seven Ig-like domains present in CEA (N and A3) has been constructed and expressed in Pichia pastoris [You, Hefta, Yazaki, Wu and Shively (1998) Anticancer Res. 18, 3193-3201]. Here, we report the generation and selection of a multi-copy clone expressing this fusion protein, the optimization of the shake-flask expression protocol and the upscaled production of CEA N-A3 using fermentation technology. P. pastoris transformants secreting the CEA N-A3 domain were generated by electrotransformation of the GS115 host strain with the pPIC9K vector containing the CEA N-A3 cDNA [You, Hefta, Yazaki, Wu and Shively (1998) Anticancer Res. 18, 3193-3201] then screened for CEA N-A3 expression and G418 resistance. The recombinant CEA N-A3 domain was detected in the culture supernatant using the monoclonal anti-CEA antibody T84.66. Optimization of methanol-induction conditions resulted in a high-methanol shake-flask expression protocol yielding significantly increased CEA N-A3 levels. Fermentation and culture conditions were optimized for 5-l working-volume fermentations and CEA N-A3 was affinity purified using Ni-IDA (imino di-acetic acid) affinity chromatography from the clarified fermentation supernatant. Peptide N-glycosidase F treatment revealed that the recombinant protein was heavily glycosylated but expressed as a single polypeptide of 28 kDa with no evidence of proteolytic degradation. Our results demonstrate that functional CEA N-A3 domain can be produced in sufficient quantities in P. pastoris for structural analysis or diagnostic applications. To our knowledge, this article represents the first report on the production of a human tumour antigen through fermentation.

Base Sequence↗
PubMed1999

[Effect of aerobic fermentation on the survival of Salmonella typhimurium (DT 104) and Escherichia coli in swine liquid manure].

In this study aerobic-thermophilic fermentation of untreated liquid pig manure was examined for the potential of inactivating pathogenic microorganisms. As microbial tracer organisms, Salmonella typhimurium DT 104 and Escherichia coli were used. An effective reduction of survival of these microorganisms could be demonstrated by aerobic fermentation at temperatures of 50 degrees C for at least 3 h. However, these optimal process conditions without the need of additional heating, can only be achieved by microbial substrate reduction. In contrast to the impact of temperature on hygienization processes, alteration of the pH value which occurs during fermentation had no or little influence on the tenacity of the tracer bacteria. Even under mesophilic reaction conditions the influence of the pH value was not measurable. A technical realisation of such an aerobic-thermophilic fermentation process for prophylactic disinfection is questionable since a large technical expenditure is necessary to control ammonia emission. Effective partial reduction of nitrogen, phosphate, and free carbon in liquid manure requires retention times of at least 48 h. However, thermophilic reaction conditions may ensure an effective hygienization of the final fermentation products.

Aerobiosis↗
PubMed2000

Equations and calculations for fermentations of butyric acid bacteria. Reprinted from Biotechnology and Bioengineering, Vol. XXVI, Pp 174-187 (1984).

A stoichiometric equation has been derived which describes the interrelations among the various products and biomass in fermentations of butyric acid bacteria. The derivation of the equation is based on an assumed ATP yield, two biological regularities, and the biochemistry of product formation of the fermentations. The equation obeys the constraints imposed on growth and product formation by thermodynamics and the biochemical topology. The validity of the equation is tested using a variety of fermentation data from the literature. The uses, improvements, limitations, and extensions of the equation are also discussed in detail. For example, the fermentation equation is used to calculate the maximal possible yields of the main fermentation products.

Bacteria↗
PubMed1999

Studies on production of pullulan by the feed batch fermentation.

The feed-batch fermentation of pullulan was investigated based on the conditions of batch fermentation. The optimal conditions of pullulan fermentation were determined by the investigation on the effect of feed mode, initial feed time, intermittent time, and composition of the feed solution on parameters such as productivity, conversion yield, biomass, dissolved oxygen (DO), pH of the fermentation broth, viscosity of the fermentation broth and molecular weight of the product. Above 70% of conversion yield and 100 kD of average molecular weight of the product was obtained at the optimal conditions.

Ammonium Sulfate↗
PubMed2000

[Obtaining a fermented chickpea extract (Cicer arietinum L.) and its use as a milk extensor].

Chickpea (Cicer arietinum L) is cultivated in the North part of México and it is considered a good source of vegetal protein of low cost (20% average), nevertheless, the 80% used for the exportation and only the 20% less was used for animal feeding. The main objective in this study is to obtain a fermented chickpea extract for using in dairy extensor. Chickpea water absorbtion kinetics were carried out in e temperature conditions:while the conditions were established, chickpea was grounded and fermented in different amounts with its natural flora, L. casei, L. plantarum and a mixture culture of both microorganism in logarithmic phase. The results showed that the presence of microorganism of chickpea natural flora interferes during the fermentation, so before the inoculation it was necessary treat the chickpea extract (CE) terminally in a dilution 1:4 during 20 min at 7.7 kg/cm2 of pressure. The use of a mixture culture of 5% of L. casei and 5% L. plantarum inoculated in MRS broth was used to decrease fermentation time. Its addition in logarithmic phase to the sterile chickpea extract increased the lactic acid production and decreased the pH value in 6 h which was less time that one obtained with each of lactobacillus. The fermented extract obtained finally, presented similar sensory characteristics to the ones of dairy products. Therefore, chickpea is a good alternative as a extensor for this kind of products.

Dairy Products↗
PubMed2000

[Two different fermentation techniques of steriod 1,4-dehydrogenation and 11 alpha-hydroxylation].

Two kinds of micro-organism, Arthrobacter sp. AX86(1,4-dehdrogenator) and Absidia sp. A28(11 alpha-hydroxylator) were used in this experiment. Two different fermentation techniques were performed to accomplish the multiple conversional reactions for producing 16 beta-methyl-11 alpha,17 alpha,21-trihydroxy-1,4-pregnadiene-3,20-dione(III) from 16 beta-methyl-3 beta,17 alpha,21-trihydroxy-5 alpha-pregnane-20-one-21-acetate(I): 1) To produce product(III) by means of a two-step fermentation method which were independently performed first by Arthrobacter and next by Absiaia, and 2) the product was obtained by a sequential fermentation system of aforesaid two micro-organisms in a single fermentor without isolation of the intermediates from the mixture. Our results showed that in both fermentation systems high yield of product was obtained. However, according to the technical simplicity, shorter duration of fermentation cycle and efficient yield of product, the second method is better than the first one.

Absidia↗
PubMed2000

Kinetics of accelerated solid-state fermentation of organic-rich municipal solid waste.

Biotransformation of landfill solid wastes is a slow process requiring decades for completion. Accelerated anaerobic fermentation in modulated landfill environments may alleviate or eliminate pollution of land, water and air. This research was undertaken to demonstrate the application of biphasic fermentation to a simulated laboratory-scale landfill to effect rapid biomethanation of biodegradable solids. The biphasic process consisted of solid-state, acidogenic fermentation of the organic fraction of MSW followed by biomethanation of acidic hydrolysates in a separate methane fermenter. Solid-state fermentation of the MSW with effluent recirculation resulted in rapid hydrolysis, acidification and denitrification, with soluble COD and VFA concentrations accumulating to inhibitory levels of 60,000 mg/l and 13,000 mg/l, respectively, at a pH of 4.5. The landfill gas methane concentration reached a maximum of 55 mol.%. By comparison, the methanogenic reactor produced high methane-content (70-85 mol.%) gases. The biphasic process effected carbohydrate, lipid, and protein conversion efficiencies of 90%, 49%, and 37%, respectively. Development of a Monod-type product-formation model was undertaken to predict methane formation and to determine kinetic parameters for the methanogenic processes in the simulated landfill and separate methane reactors. A first-order solids hydrolysis rate constant of 0.017 day-1 was evaluated to show that landfill solids hydrolysis was slower than the inhibited methanogenesis rate.

Bacteria, Anaerobic↗