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Aims To quantify and model the combined effects of temperature ( T) (10-40°C), water activity ( aw) (0·993-0·818) and CO2 concentration (9·4-55·1%, v/v) on the growth rate of Aspergillus niger and Alternaria alternata that cause spoilage during the storage and packaging of dates. Methods and Results The effects of environmental factors were studied using the γ-concept. Cardinal models were used to quantify the effect of studied environmental factors on the growth rates. Firstly, the cardinal parameters were estimated independently from experiments carried out on potato dextrose agar using a monofactorial design. Secondly, model performance evaluation was conducted on pasteurized date paste. The boundary between growth and no-growth was predicted using a deterministic approach. Aspergillus niger displayed a faster growth rate and higher tolerance to low aw than Al. alternata, which in turn proved more resistant to CO2 concentration. Minimal cardinal parameters of T and aw were lower than those reported in the literature. Conclusions The combination of the aw and CO2 effects significantly affected As. niger and Al. alternata growth. The γ-concept model overestimated growth rates, however, it is optimistic and provides somewhat conservative predictions. Significance and Impact of the Study The developed model provides a decision support tool for the choice of the date fruit conservation mode (refrigeration, drying, modified atmospheric packaging or their combination) using T, aw and CO2 as environmental factors. [ABSTRACT FROM AUTHOR]

Glucose, fructose, sucrose and starch are naturally present in cereals. Fermentation of different combinations of these carbohydrates by Lactobacillus fermentum Ogi E1, a sourdough heterofermentative lactobacillus, was investigated to determine effects on fermentation kinetics, growth energetics and α-amylase production. Irrespective of the substrate combination, the strain was able to simultaneously produce α-amylase and consume starch, glucose, fructose and sucrose. In mixtures of starch with either sucrose or fructose or with both fructose and glucose, yields of α-amylase from biomass (Yamy/x) were similar to those observed for starch. However, for starch and glucose or starch, glucose, fructose and sucrose mixtures, both Yamy/x and the specific rate of α-amylase production decreased markedly. In fructose- or sucrose-containing mixtures, mannitol was formed stoichiometrically indicating that fructose served as electron acceptor, and acetate was produced at constant yield from biomass (Yac/x) (1 g acetate g biomass−1). Acetate production was expected to confer to the strain a competitive advantage during natural fermentation by improving biomass formation and growth through an increase in the ATP gain. YATP varied depending on the carbohydrate mixture, indicating different effects of substrate mixtures on the efficiency in ATP coupling to biomass formation. Compared to starch fermentation, the highest value of YATP (29 g biomass mol ATP−1) was estimated for the starch/fructose mixture but no increase in μmax was observed. The lowest value (16 g biomass mol ATP−1) was obtained for the starch, glucose and fructose mixture, whereas for the mixture of all carbohydrates, YATP was similar to that obtained with starch alone (20 g biomass mol ATP−1) and it was intermediary for the starch and sucrose mixture (17 g biomass mol ATP−1). It is concluded that competitiveness of the strain cannot be based on expected energy gain in mixed substrate fermentation involving fructose and sucrose with glucose and starch, but rather on its ability to simultaneously use carbohydrates while producing α-amylase and to produce acetic acid. Acetic acid production could enhance the strain capacity to inhibit nonacid-tolerant, competitive microflora at the earlier stage of natural fermentation. [Copyright &y& Elsevier]

Lactobacillus fermentum Ogi E1 is an amylolytic heterofermentative lactic acid bacterium previously isolated from ogi, a Benin maize sourdough. In the present study, the effect of different pH between 3.5 and 6.0 on starch fermentation products and α-amylase production was investigated. Whereas a pH of 5.0 was optimum for specific growth rate and lactic acid production, growth was only slightly affected at suboptimal pH of 4.0 and 6.0. Over a pH range of 6.0 to 3.5, yields of product formation from substrate and of biomass relative to ATP were constant. These results showed that L. fermentum Ogi E1 was particularly acid tolerant, and well adapted to the acid conditions that develop during natural fermentation of cereal doughs. This acid tolerance may partly explain the dominance of L. fermentum in various traditional African sourdoughs. Surprisingly, α-amylase production, unlike growth, dropped dramatically when the strain was cultivated at pH 4.0 with starch. With maltose as substrate, the yield of α-amylase relative to biomass remained unchanged at pH 4.0 and 5.0, unlike that observed with starch. Based on the distribution of enzyme activity between extra- and intracellular fractions and fermentation kinetics, it appears that starch was first hydrolyzed into dextrins by α-amylase activity, and maltose was produced from dextrins by extracellular enzyme activity, transferred into the cell and then hydrolyzed into glucose by intracellular α-glucosidase. [Copyright &y& Elsevier]

The aromatic quality of chocolate requires the use of cocoa with high aromatic potential, this being acquired during the fermentation of cocoa beans. Traditional fermentation is still often carried out on a small scale with wild strains of yeasts and acetic bacteria and under poorly controlled conditions leading to cocoa quality ranging from best to worst. This study is the first part of a project aiming to control quality of cocoa to produce high aromatic quality chocolate by using a mixed starter of selected strains of yeast and acetic bacteria and by controlling the conditions of fermentation. To achieve this objective, a mathematical model of the alcoholic fermentation of cocoa beans has been developed. The growth, glucose consumption and ethanol production of Saccharomyces cerevisiae LM strain in synthetic broth were modeled for the most important intrinsic (pH, glucose, ethanol, free nitrogen and oxygen levels) and extrinsic (temperature, oxygen level) fermentation parameters. The model was developed by combining the effects of individual conditions in a multiplicative way using the gamma concept. The model was validated in liquid synthetic medium at two different inoculation levels 10 4 and 10 6  CFU/mL with an increase in temperature that recorded during spontaneous fermentations. The model clearly shows that the level of inoculation and the speed of the increase in temperature clearly drive yeast growth, while other factors including pH and ethanol, free nitrogen and oxygen levels have no significant impact on yeast growth., (Copyright © 2020. Published by Elsevier B.V.)

This paper describes a mixed fermentation model made by assembling block hosting models for the growth of lactic acid bacteria (Lactobacillus plantarum) and a yeast strain (Pichia kluyveri), metabolic production and the physical-chemical changes which occur during the fermentation of gowé. The growth model for P. kluyveri was developed on a synthetic medium following the gamma concept taking into account the effect of pH, temperature, concentrations in glucose, lactic acid and ethanol. Additional parameters for the previously defined L. plantarum growth model were also determined (glucose and ethanol concentrations). The model was validated in three different gowé processing conditions. Even if the model underestimates LAB growth, it explains what occurs in the product and enables in silico extrapolation to various fermentation conditions. The predicted hydrolysis rates of native and gelatinised starches showed that increasing malt content is not an efficient way to increase the sweetness of gowé in contrast to increasing the level of pre-cooking. The builing-block model developed in this study could be applied to many other fermented foods and particularly to non-alcoholic but acid and sweet cereal based beverages., (Copyright © 2019. Published by Elsevier Ltd.)

Gowé is an acidic beverage obtained after simultaneous saccharification and fermentation (SSF) of sorghum. A previous paper focused on modeling the growth of lactic acid bacteria during gowé processing. This paper focuses on modeling starch amylolysis to build an aggregated SSF model. The activity of α-amylase was modeled as a function of temperature and pH, and the hydrolysis rates of both native and soluble starch were modeled via a Michaelis-Menten equation taking into account the maltose and glucose inhibition constants. The robustness of the parameter estimators was ensured by step by step identification in sets of experiments conducted with different proportions of native and gelatinized starch by modifying the pre-cooking temperature. The aggregated model was validated on experimental data and showed that both the pre-cooking and fermentation parameters, particularly temperature, are significant levers for controlling not only acid and sugar contents but also the expected viscosity of the final product. This generic approach could be used as a tool to optimize the sanitary and sensory quality of fermentation of other starchy products., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

DNA methylation is a highly conserved epigenetic modification with critical roles ranging from protection against phage infection in bacteria to the regulation of gene expression in mammals. DNA methylation at specific sequences can be measured by using methylation dependent or sensitive restriction enzymes coupled to semi- or quantitative PCR (MD-qPCR). This study reports a refined MD-qPCR method for detecting gain or loss of DNA methylation at specific sites through the specific use of MspJI or HpaII, respectively. By employing varying concentrations of DNA with methylation ranging from 0 to 100%, our data provide evidence that compared to HpaII, MspJI increases the sensitivity and accuracy of detecting relative DNA methylation gains by MD-qPCR. We also show that the MspJI-coupled MD-qPCR can accurately determine the percent gain in DNA methylation at the Sall4 enhancer and is more sensitive than HpaII in detecting relative gains in DNA methylation at the Oct4 proximal enhancer during embryonic stem cell (ESC) differentiation. The high specificity and sensitivity of this targeted approach increases its potential as a diagnostic tool to detect relatively smaller gains in DNA methylation at specific sites from limited amounts of sample., (Copyright © 2017 Elsevier Inc. All rights reserved.)

A global model of the lactic fermentation step of gowé was developed by assembling blocks hosting models for bacterial growth, lactic acid production, and the drop of pH during fermentation. Commercial strains of Lactobacillus brevis and of Lactobacillus plantarum were used; their growth was modeled using Rosso's primary model and the gamma concept as a secondary model. The optimum values of pH and temperature were 8.3 ± 0.3, 44.6 ± 1.2 °C and 8.3 ± 0.3, 3.2 ± 37.1 °C with μ max values of 1.8 ± 0.2 and 1.4 ± 0.1 for L. brevis and L. plantarum respectively. The minimum inhibitory concentration of undissociated lactic acid was 23.7 mM and 35.6 mM for L. brevis and L. plantarum , respectively. The yield of lactic acid was five times higher for L. plantarum than for L. brevis , with a yield of glucose conversion to lactic acid close to 2.0 for the former and 0.8 for the latter. A model was developed to predict the pH drop during gowé fermentation. The global model was partially validated during manufacturing of gowé. The global model could be a tool to aid in the choice of suitable starters and to determine the conditions for the use of the starter., Competing Interests: The authors declare no conflict of interest

The objective of the present work was to estimate the prevalence of Bacillus cereus group species in traditional cereal-based lactic acid-fermented slurries and nonfermented flours used to prepare infant foods in an African context. High counts on mannitol-egg yolk-polymixin agar medium were determined for the fermented slurries (median, 4.5 × 10(4) CFU/ml of slurry) compared with the nonfermented flours, most of whose counts were lower than 10(-1) CFU/g. Virulence genes were characterized in 60 isolates from 26 traditional cereal-based foods in Ouagadougou (Burkina Faso). Seventy-two and 38 % of isolates were positive for the complete set of genes coding for hemolysin BL and nonhemolytic enterotoxin, respectively, suggesting a high enterotoxigenic potential for these foodborne isolates. No potentially emetic toxin-producing strains were detected. Because of the high counts found for fermented slurries, survival tests with vegetative cells inoculated in fermented slurries were performed, which showed that growth of B. cereus was inhibited. This result suggests that fermentation in traditional production units is presumably not adequately controlled, enabling growth during any unit operations before fermentation, or even during the fermentation step, when the process was poorly controlled. However, adding nisin (0.1 mg/ml) enabled a 5-log reduction in the B. cereus population in 5 h, suggesting that the use of nisin could be a way to upgrade the hygienic quality of this type of food.

Unlabelled: This study examined the feasibility of coupling dehydration-impregnation by soaking (DIS) with a subsequent lactic fermentation in the treatment of meat. A series of beef fillets were subjected to 3 different DIS treatments. The resulting DIS-treated fillets had 3 different characteristics in terms of water activity, salt, and fermentable sugars contents. Fillets treated with the DIS with the shortest immersion time (5 h) and the highest salt concentration in the DIS bath (100 g/L) were inoculated with Lactobacillus sakei. A control group was left without inoculation. After 24 h incubation at 25 °C, only inoculated fillets showed signs of lactic fermentation. At 24 h, these fillets had a d-lactic acid content of 68 μmol/g dry basis and a high population of L. sakei revealed by methods of plate count and quantitative PCR. DIS could therefore be compatible with a subsequent fermentation step by L. sakei., Practical Application: Traditional meat preservation processes often combine unit operations such as salting, smoking, fermentation, and drying. In tropical countries, high temperatures and high relative humidity, poor infrastructure, and improper slaughterhouse practices explain the need for more drastic processes (more salt, more water loss) for meat preservation. Dehydration-impregnation by soaking (DIS) could be used as a rapid pretreatment of meat, in order to counteract tropical conditions. This study validates a novel approach whereby DIS is coupled with lactic fermentation by surface inoculation with Lactobacillus sakei. With a final drying step this process could be used for the treatment of whole meat pieces., (© 2012 Institute of Food Technologists®)

A group of 291 Staphylococcus aureus isolates from mastitic cow's milk (n = 125), bulk tank milk (n = 96), and Minas frescal cheese (n = 70) were screened for staphylococcal enterotoxin (SE) genes (sea, seb, sec, sed, see, seg, seh, sei, selj, and sell) and for the tst-1 gene encoding staphylococcal toxic shock syndrome toxin 1 by PCR assay. A total of 109 (37.5%) of the isolates were positive for at least one of these 11 genes, and 23 distinct genotypes of toxin genes were observed. Of the S. aureus isolates bearing SE genes, 17 (13.6%) were from mastitic cow's milk, 41 (41.7%) were from bulk tank milk, and 51 (72.9%) were from Minas frescal cheese. The occurrence of exclusively more recently described SE genes (seg through sell) was considerably higher (87 of 109 PCR-positive strains) than that of classical SE genes (sea through see, 15 strains). The SE genes most commonly detected were seg and sei; they were found alone or in different combinations with other toxin genes, but in 60.8% of the cases they were codetected. No strain possessed see. The tst-1 gene was found in eight isolates but none from mastitic cow's milk. Macrorestriction analysis of chromosomal DNA from 89 S. aureus isolates positive for SE gene(s) was conducted with the enzyme SmaI. Fifty-five distinct pulsed-field gel electrophoresis patterns were found, demonstrating a lack of predominance of any specific clone. A second enzyme, Apa I, used for some isolates was less discriminating than Sma I. The high genotype diversity of potential toxigenic S. aureus strains found in this study, especially from Minas frescal cheese, suggests various sources of contamination. Efforts from the entire production chain are required to improve consumer safety.

The change in the composition of camel milk in four dromedaries was studied by including the common measured parameters: protein, total fat, lactose, main minerals (calcium, phosphorus, and iron), and vitamin C. The fat matter varied from 4.34% to 7.81% with a slight decrease all along the lactation and a minimal value at the 14th week corresponding to the lactation peak. Those variations were less important for protein content (from 2.58% to 3.64%), but the minimal value was observed at the 14th week also. The lactose varied slightly around its mean of 3.46%. The vitamin C concentration varied from 48 to 256 mg/l with a tendency of increasing all along the lactation. Calcium and phosphorus concentrations were quite parallel and their ratio Ca/P was constant. The minimal values (1.43 g/l for calcium and 1.16 g/l for phosphorus) were observed at the beginning of the lactation. The iron concentrations varied around the mean of 1.73 mg/l.

The determination of geographical origin is a demand of the traceability system of import-export food products. One hypothesis for tracing the source of a product is by global analysis of the microbial communities of the food and statistical linkage of this analysis to the geographical origin of the food. For this purpose, a molecular technique employing 26S rDNA profiles generated by PCR-DGGE was used to detect the variation in yeast community structures of three species of Physalis fruit (Physalis ixocarpa Brat, Physalis pubescens L, Physalis pruinosa L) from four Egyptian regions (Qalyoubia, Minufiya, Beheira and Alexandria Governments). When the 26S rDNA profiles were analysed by multivariate analysis, distinct microbial communities were detected. The band profiles of Physalis yeasts from different Governments were specific for each location and could be used as a bar code to discriminate the origin of the fruits. This method is a new traceability tool which provides fruit products with a unique biological bar code and makes it possible to trace back the fruits to their original location.

Cocoa fermentation was monitored at the IDIAF (Instituto Dominicano de Investigaciones Agropecuarias y Forestales) "Mata Larga" experimental station, in San Francisco de Macoris, Dominican Republic. The maximum average fermentation temperature reached 51 degrees C after 48 h and the pH reached 4.5 after 144 h of fermentation. A significant decrease in glucose, fructose and citric acid was seen in the pulp over the first 48 h. There was a delay of 24 h between maximum microbial growth and maximum concentrations of the respective metabolites, which occurred after 48 h for ethanol and after 72 h for acetic acid. A maximum concentration in lactic acid was found after around 120 h of fermentation. The aerobic mesophilic flora increased from 6.1x10(6) to a maximum of 4.2x10(7) CFU g(-1) of dry matter after 48 h of fermentation. Yeasts displayed maximum development after 24 h (6.1x10(7) CFU g(-1) of dry matter), whilst for lactic and acetic acid bacteria it occurred after 48 h (7.3x10(7) and 1.5x10(8) CFU g(-1) of dry matter respectively). The yeasts isolated belonged to the genera Hanseniaspora and Candida, the lactic acid bacteria to the genus Lactobacillus, and the acetic acid bacteria to the genus Acetobacter. The differences compared to other fermentation trials concerned the micropopulation from a qualitative point of view.

The lactoperoxidase system (LPS) was evaluated for the prevention of postharvest diseases caused by Xanthomonas campestris, Botryodiplodia theobromae, and Colletotrichum gloeosporioides in 'Keitt' and 'Kent' mangoes. The LPS treatment significantly reduced the disease development on both cultivars after storage at 12 degrees C for 2 weeks, which was followed by a ripening at 25 degrees C. The LPS treatment did not alter the sensory quality of mango fruits (color, firmness, titrable acidity, and total soluble solids) when compared to untreated fruits. The LPS thus presents good potential alternative to the chemical fungicides traditionally used to improve the shelf life of mangoes.

The antibacterial activity of the lactoperoxidase system (LPS) on the growth of Xanthomonas campestris, the causal agent of bacterial black spot in mangoes, Botryodiplodia theobromae, the causal agent of stem-end rot disease in mangoes, and Colletotrichum gloeosporioides, the causal agent of anthracnose disease in mangoes, was determined during culture at 30 degrees C and at several pH values (4.5, 5.5, and 6.5). When the results of using the LPS were compared with those from control cultures without the LPS reagents, the growth of the three microorganisms was totally inhibited in all of the conditions tested. Viability tests enumerating cultivable cells of X. campestris showed that the LPS had a bactericidal effect, whatever the pH value. This effect is faster at pH 5.5, corroborating the results reported in the literature (optimal pH for the LPS efficiency). Further, we proved that hydrogen peroxide alone had little inhibition effect on the growth of the microorganisms studied. This compound is essentially used to convert thiocyanate into hypothiocyanate during the lactoperoxidase reaction. The potential of the LPS for the postharvest treatment of the fruits for controlling microbial diseases was thus demonstrated. Nevertheless, further studies are needed on fresh fruits before envisaging any application.

2-Methylamino-4-N-methylpiperazino-5-methylthio-6-chloropyrimidine hydrochloride (O 6553) is a new molecule showing an original pharmacological profile in the laboratory tests. It possesses at the same time potent gastro-intestinal prokinetic and central antiemetic properties, demonstrated on the one hand by the gastro-duodenal transit of barium meal in rats, and on the other hand by apomorphine-induced vomiting in dogs. The drug also has interesting anxiolytic and antiserotonin properties and, at doses which change gastro-intestinal behaviour, it is devoid of any untoward side effect. The acute and subacute toxicities of O 6553 show that the drug has a very good safety margin.

We have synthetized a series of 22 new 4-piperazinopyrimidines bearing a methylthio substituent in the 5 position of the pyrimidine ring. These compounds have been obtained by separation of the isomers formed during nucleophilic attack of the corresponding 2,4,6-trichloropyrimidine by amines. Pharmacological screening has shown that this chemical series displays a very interesting profile, which includes antiemetic, tranquilizing, analgesic, antiserotonin, and musculotropic-spasmolytic properties. We have particularly selected for clinical investigations two compounds with powerful antiemetic activity: 2-methylamino-4-(N-methylpiperazino)-5-methylthio-6-chloropyrimidine and 2-isopropylamino-4-(H-methylpiperazino)-5-methylthio-6-chloropyrimidine.

The absorption and metabolism of clofibride, a new hypolipaemic drug of p-chlorophenoxyisobutyric type, were investigated in the CD rat, the beagle and the olive baboon monkey. Clofibride is rapidly and massively resorbed and hydrolysed into 4-chlorophenoxyisobutyric acid (CPIB) and 4-hydroxy-N-dimethylbutyramide (HMB). CPIB, in free and glucuroconjugated form, and its metabolite, 4-chlorophenol, in the form of the glucuronate ether, are found in the serum of the rat. HMB is rapidly metabolized. The half-life of CPIB, the main active metabolite, in the serum is about 12 h in the rat, 43 +/- 9 h in the dog and 6 +/- 1 h in the baboon. In the rat, peak hypocholesterolaemic activity occurs late--24 h after administration of the drug and 20 h after peak concentration of CPIB in the blood. The half-life of 4-chlorophenol glucuronate ether in the serum is about 4 h whereas that of HMB is about 3 h. In the rat, the elimination of clofibride takes place mainly via the urine since 70% of the dose administered is found in the form of free or conjugated CPIB, 10% in the form of HMB or one of its metabolites, in 48 h samples of urine. Over the same period, faecal elimination accounts for no more than 2% of the dose ingested. In addition, in this species, the CPIB, 30% of which is secreted via the biliary route without being eliminated in the faeces, undergoes an enterohepatic circulation.