Stimulation of aflatoxin B1 and T-2 toxin production by sorbic acid

Occurrence, Risk Implications, Prevention and Control of CIT in Monascus Cheese: A Review

Monascus is a filamentous fungus that has been used in the food and pharmaceutical industries. When used as an auxiliary fermenting agent in the manufacturing of cheese, Monascus cheese is obtained. Citrinin (CIT) is a well-known hepatorenal toxin produced by Monascus that can harm the kidneys structurally and functionally and is frequently found in foods. However, CIT contamination in Monascus cheese is exacerbated by the metabolic ability of Monascus to product CIT, which is not lost during fermentation, and by the threat of contamination by Penicillium spp. that may be introduced during production and processing. Considering the safety of consumption and subsequent industrial development, the CIT contamination of Monascus cheese products needs to be addressed. This review aimed to examine its occurrence in Monascus cheese, risk implications, traditional control strategies, and new research advances in prevention and control to guide the application of biotechnology in the control of CIT contamination, providing more possibilities for the application of Monascus in the cheese industry.

Incretin Mimetics as Rational Candidates for the Treatment of Traumatic Brain Injury

Traumatic brain injury (TBI) is becoming an increasing public health issue. With an annually estimated 1.7 million TBIs in the United States (U.S) and nearly 70 million worldwide, the injury, isolated or compounded with others, is a major cause of short- and long-term disability and mortality. This, along with no specific treatment, has made exploration of TBI therapies a priority of the health system. Age and sex differences create a spectrum of vulnerability to TBI, with highest prevalence among younger and older populations. Increased public interest in the long-term effects and prevention of TBI have recently reached peaks, with media attention bringing heightened awareness to sport and war related head injuries. Along with short-term issues, TBI can increase the likelihood for development of long-term neurodegenerative disorders. A growing body of literature supports the use of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), and glucagon (Gcg) receptor (R) agonists, along with unimolecular combinations of these therapies, for their potent neurotrophic/neuroprotective activities across a variety of cellular and animal models of chronic neurodegenerative diseases (Alzheimer's and Parkinson's diseases) and acute cerebrovascular disorders (stroke). Mild or moderate TBI shares many of the hallmarks of these conditions; recent work provides evidence that use of these compounds is an effective strategy for its treatment. Safety and efficacy of many incretin-based therapies (GLP-1 and GIP) have been demonstrated in humans for the treatment of type 2 diabetes mellitus (T2DM), making these compounds ideal for rapid evaluation in clinical trials of mild and moderate TBI.

New strategies for minimally processed foods. The role of multitarget preservation/Nuevas estrategias para los alimentos mínimamente procesados. La conservación "multiblanco"

Minimally processed foods represent a problem from the point of view of microbiological safety, since their processing implies a loss of extrinsic and intrinsic preservation factors. This paper analyzes the microbiological status of minimally processed foods and the prospects to extend their microbiological safety by the hurdles technology. Some issues to be taken into account for this technology are also considered

Effect of weak acid preservatives on growth of bakery product spoilage fungi at different water activities and pH values

Inhibition of spoilage organisms from bakery products by weak acid preservatives in concentrations of 0%, 0.003%, 0.03% and 0.3% (w/v) was investigated experimentally on a substrate media with water activity (a(w)) and pH ranging from sourdough-fermented acidic rye bread to alkaline intermediate moisture sponge cake types (a(w) 0.80-0.95, pH 4.7-7.4). Initially, rye bread conditions (a(w) 0.94-0.97 and pH 4.4-4.8) in combination with calcium propionate were investigated. Results showed that the highest concentration of propionate (0.3%) at all conditions apart from high a(w) (0.97) and high pH (4.8) totally inhibited fungal growth for a 2-week period, with the exception of Penicillium roqueforti, Penicillium commune and Eurotium rubrum. Characteristically for the major spoiler of rye bread, P. roqueforti, all three isolates tested were stimulated by propionate and the stimulation was significantly enhanced at high water activity levels. The effect of propionate on production of secondary metabolites (mycophenolic acid, rugulovasine, echinulin, flavoglaucin) was also studied, and variable or isolate dependent results were found. Subsequently, a screening experiment representing a wider range of bakery products was conducted using calcium propionate, potassium sorbate and sodium benzoate. The obtained data was modelled using survival analysis to determine 'spoilage-free time' for the fungi. At the low a(w) level (0.80) only Eurotium species grew within the test period of 30 days. Higher water activity levels as well as higher pH values decreased spoilage-free times of the fungi. The preservative calcium propionate was less effective than potassium sorbate and sodium benzoate.

Mycotoxins and fermentation--beer production

Along with food safety issues due to mycotoxins, the effects of Fusarium infections on malt and beer quality can be disastrous. While some of the Fusarium head blight mycotoxins, such as DON, present in infected barley may be lost during steeping, the Fusarium mold is still capable of growth and mycotoxin production during steeping, germination and kilning. Therefore, detoxification of grain before malting may not be practical unless further growth of the mold is also prevented. Methods for reducing the amount of mold growth during malting are needed. Physical, chemical and biological methods exist for inhibiting mold growth in grain. Irradiation is a promising means for preventing Fusarium growth during malting, but its effects on malt quality and mycotoxin production in surviving mold need to be evaluated in more detail. Chemical treatments such as ozonation, which do not leave chemical residues in beer, also appear to be promising. Although biological control methods may be desirable, the effects of these inhibitors on malt and beer quality require further investigation. In addition, storage studies are needed to determine the effect of biological control on Fusarium viability and malt quality. It may also be possible to incorporate detoxifying genes into fermentation yeasts, which would result in detoxification of mycotoxins present in wort. Development of these types of technological interventions should help improve the safety of products, such as beer, made from Fusarium infected grain.

Effect of novel water-soluble polymeric forms of sorbic acid against Fusarium oxysporum f.sp. radicis-cucumerinum

New controlled release water-soluble formulations of sorbic (2,4-hexadienoic) acid were prepared and their inhibitory activity on mycelium growth of Fusarium oxysporum f.sp. radicis-cucumerinum was evaluated. The new products are epoxidized polymers of polyvinylpyrrolidone (PVP) containing covalently bonded sorbic acid (polymeric esters of sorbic acid) and complexes of PVP with hydrogen bonded sorbic acid, characterized by controlled release of sorbic acid. It was shown that the polymeric complexes of sorbic acid with PVP were more effective fungicidal agents than sorbic acid polymeric esters. In all cases the activity of polymeric derivatives (esters and complexes) was increased by lowering the molecular weight of the polymeric carriers. Controlled release formulations of these polymeric derivatives are new promising products due to their low toxicity, wide range of efficient concentrations for application and ability to regulate lyophilicity. Our data contribute to the understanding of the action mechanism of various polymeric sorbic acid formulations and can result in products which are particularly suitable for food and feed protection applications.

Effect of common food preservatives on mycelial growth and spore germination of Fusarium oxysporum

The growth and spore germination inhibition of Fusarium oxysporum f.sp. radicis-cucumerinum by the common food additives: acetic acid, formic acid potassium sorbate, propionic acid, sorbic acid, and the fungistatic agent sec-butylamine was examined in vitro. The inhibitory efficacy of these chemicals decreased in the following order: sorbic acid, potassium sorbate, propionic acid, acetic acid, sec-butylamine and formic acid. At pH 6.4, the ED50 value for mycelium growth was: 976 ppm for sorbic acid, 1292 ppm for potassium sorbate, 2435 ppm for propionic acid, 3805 ppm for acetic acid, 3962 ppm for sec butylamine and 4668 ppm for formic acid. The ED50 value for spore germination was: 225 ppm for potassium sorbate, 1201 ppm for sorbic acid, 1402 ppm for propionic acid, 1600 ppm for sec-butylamine, 1957 ppm for acetic acid and 2485 ppm for formic acid.

Effects of food preservatives on Alternaria alternata growth and tenuazonic acid production

The effects of different organic acids on Alternaria alternata growth and tenuazonic acid production (TeA) were evaluated. Both TeA pure toxin solution and TeA production in solid medium were considered. Sodium benzoate, potassium sorbate and sodium propionate, all preservatives commonly used by food industry in Argentina, were tested. TeA was stable as pure toxin solution when was treated with the salts of organic acids used. A differential effect was observed when the preservatives were evaluated in relation to A. alternata growth and TeA production in solid medium. Levels above 10 mg/kg of sodium benzoate and potassium sorbate produced a total inhibition of fungal development and toxin biosynthesis. Sodium propionate produced a 59% decrease in A. alternata growth and total inhibition of TeA production only at the highest concentration of preservatives used.

[Effect of the fungicide matador (tebuconazole/triadimenol) on mycotoxin production by Fusarium culmorum]

Applications of the fungicide Matador to winter wheat (Slejpner) inoculated at earing with Fusarium culmorum resulted in a considerable decrease in the incidence of Fusarium headblight. In the study presented here, subsequent mycotoxin analyses by selected ion monitoring gas chromatography-mass spectrometry revealed higher levels of nivalenol (NIV) in samples singly treated with Matador at 1 L/ha. Amounts as high as 2432 micrograms NIV/kg and 860 micrograms NIV/kg, representing a 16- or six-fold increase as compared to controls, were found in wheat treated with the fungicide 3 h before or 24 h after inoculation of the grain with F. culmorum, respectively. In parallel, higher cytotoxic activities of these samples were obtained when testing crude sample extracts in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-cell culture bioassay using swine kidney monolayers as target cells. It is concluded that treatment of grain with the fungicide Matador could result in a marked stimulation of the production of NIV by F. culmorum. As the incidence of Fusarium headblight did not correlate with the amount of mycotoxins found, the need for mycotoxin analyses combined with bioassays such as the MTT-cell culture assay is recommended for a meaningful assessment of the quality of grain treated in such a manner.

Effect of some food preservatives on aflatoxin production

The effect of some food preservatives, such as sorbic (SA) and propionic (PA) acids, on aflatoxin production in synthetic media or in moistened (20%) wheat seeds, was investigated. The preservatives tested, added to synthetic media at sublethal concentrations both at the inoculum and after 5 days of incubation, stimulated aflatoxin production by Aspergillus parasiticus. Sorbic and propionic acids are metabolized by the fungus in vivo and in vitro. Lower concentrations of PA and SA (0.05 to 0.1% w/w) in wheat seeds are ineffective against both fungal growth and aflatoxin production, whilst the combined use of butylated hydroxy toluene (BHT), and PA or SA was more effective in controlling aflatoxin production than their use as single components.

Aflatoxins in food: occurrence, biosynthesis, effects on organisms, detection, and methods of control

Aflatoxins are secondary metabolites produced by species of Aspergilli, specifically Aspergillus flavus and Aspergillus parasiticus. These molds are ubiquitous in nature and grow on a variety of substrates, thereby producing aflatoxins. Aflatoxins are of great concern due to their biochemical and biological effects on living organisms. In this article, the occurrence of aflatoxins, their biosynthesis, factors influencing their production, their effects on living organisms, and methods of detection and control in food are reviewed. Future areas of research involving mathematical modeling of factors influencing aflatoxin production and alternative methods of control, such as modified atmosphere packaging, are also discussed.

The incidence of Listeria monocytogenes in raw milk from farm bulk tanks in north-east Scotland

Over 180 farm bulk milk tanks were tested for the presence of Listeria monocytogenes on three separate occasions which included periods when cows were grazing and confined inside on a silage diet. The incidence of L. monocytogenes contamination was low, ranging from 3.8% in the summer samples to 1.0% in October. The level of contamination was estimated to be lower than one L. monocytogenes bacterium per ml in positive samples, as most required cold enrichment of 10-20 ml volumes before recovery. The distribution was sporadic; only one farm gave positive isolations on all three sampling occasions, one other on two, and all others were from different farms. No correlation between the presence of L. monocytogenes and hygiene standards or the feeding of silage was found.

Growth and aflatoxin production by Aspergillus parasiticus in a medium at different pH values and with or without pimaricin

A glucose-yeast extract-salt medium containing 0, 5, 7.5, 10, 15 or 20 micrograms pimaricin/ml with an initial pH of 3.5 or 5.5 was inoculated with Aspergillus parasiticus WB 108 and incubated at 15 degrees or 28 degrees C. The pH, weight of mycelium and amount of aflatoxin produced were determined after 3, 7, and 10 days and after 14, 21, and 30 days when incubation was at 28 degrees or 15 degrees C, respectively. Increasing the concentration of pimaricin in the medium with an initial pH of 5.5 decreased the amounts of aflatoxin B1 and G1 produced after 3 days of incubation. When the initial pH of the medium was 3.5, no growth or toxin production occurred after 3 days of incubation in the medium containing 7.5 micrograms or more of pimaricin/ml. The presence of 20 micrograms of pimaricin/ml inhibited growth and toxin production after 7 days of incubation. When cultures were incubated at 15 degrees C, there was a lag phase which extended from 9 to 16 days, and the amounts of aflatoxin produced decreased with an increasing concentration of pimaricin. Pimaricin did not completely inhibit the growth and aflatoxin production by A. parasiticus. Pimaricin, in combination with a low pH, low temperature or 4% or 6% NaCl, initially caused slow mycelial growth and low toxin production, but the mold overcame the inhibitory effects and produced substantial amounts of mycelium and toxin.

Influence of metabolic and physical factors on production of diacetoxyscirpenol by Fusarium sambucinum Fuckel

Fusarium sambucinum Fuckel 8099-1 was grown on Czapek-Dox peptone-supplemented medium at 15 degrees C for 14 days, and the cultures were investigated for diacetoxyscirpenol (DAS) production by liquid-liquid extraction and gas chromatography. The addition of 150 mg of sorbic acid, a tricarboxylic acid cycle inhibitor, per liter stimulated both fungal growth and DAS production. Among the beta-hydroxy-beta-methylglutaryl coenzyme A precursors tested, isovaleric acid completely inhibited fungal growth and DAS production, ethyl isovalerate did not support a significant increase in DAS production, and L-leucine partially inhibited DAS production, showing that L-leucine and isovaleric acid catabolisms do not induce trichothecene biosynthesis. Solid particles (cork powder) were necessary for DAS production in stationary cultures but did not influence DAS production in shaken cultures. Shaking strongly stimulated DAS production and fungal growth.

Food additives and plant components control growth and aflatoxin production by toxigenic aspergilli: a review

Growth and aflatoxin production by toxigenic aspergilli are partially or completely inhibited by the undissociated form of acetic, benzoic, citric, lactic, propionic and sorbic acids. Salts such as sodium chloride, potassium chloride and sodium nitrate, at low concentrations, can enhance aflatoxin production. At higher concentrations they become inhibitory, but marked inhibition requires amounts of the salts greater than are commonly used in foods. Phenolic antioxidants, sometimes added to foods to prevent oxidative deterioration, also are inhibitory to toxigenic aspergilli. Other inhibitory agents include certain insecticides, methylxanthines (caffeine and theophyllin), and components of some herbs, spices and other plants.

Thin-layer chromatography of mycotoxins

TLC has become an extremely powerful, rapid and in most instances inexpensive separation technique in mycotoxicology. This review presents achievements of its applications in this field. General technical aspects of the TLC of mycotoxins that are discussed include extraction and clean-up procedures, adsorbents and solvent systems, detection methods, two-dimensional TLC, high-performance TLC (HPTLC), quantitation and preparative TLC (PLC). Special applications of TLC deal with multi-mycotoxin analyses and with structurally related or individual mycotoxins (aflatoxins, sterigmatocystins, versicolorins, ochratoxins, rubratoxins, patulin, penicillic acid, mycophenolic acid, butenolide, citreoviridin, trichothecenes, cytochalasans, tremorgenic toxins, epipolythiopiperazine-3,6-diones, hydroxyanthraquinones, zearalenone, citrinin, secalonic acids, cyclopiazonic acid, PR toxin, roquefortine, xanthomegnin, viomellein and naphtho-gamma-pyrones).

Trichothecene Production in Liquid Stationary Cultures of Fusarium tricinctum NRRL 3299 (Synonym: F. sporotrichioides ): Comparison of Quantitative Brine Shrimp Assay with Physicochemical Analysis

Stationary liquid cultures of Fusarium tricinctum NRRL 3299 (synonym: F. sporotrichioides ) produce T-2 toxin, neosolaniol, diacetoxyscirpenol, and HT-2 toxin when cultured on peptone-enriched Czapek Dox medium. At 15 and 27°C, maximum T-2 toxin yield (265 and 50 μg/ml) was found after 10 to 14 and 7 days, respectively. The T-2 toxin in the culture medium was metabolized rapidly at 27°C and slowly at 15°C. Addition of 0.025% (wt/vol) sorbic acid to the medium resulted in an increased production of trichothecenes at 15°C (400 μg of T-2 per ml after 14 days). Trichothecenes in the culture liquid were determined by the brine shrimp bioassay and physicochemical analysis. The brine shrimp assay was improved by using modern bioassay equipment, including tissue culture trays and multipipettes, and by a standardized approach with positive and negative controls. The physicochemical analysis was based on adsorption of the trichothecenes onto Amberlite XAD-2 columns, derivatization with trifluoroacetic anhydride followed by capillary gas chromatography, and identification by mass spectrometry (as many as 17 trichothecenes were detected in the culture medium). The brine shrimp assay offers an interesting monitoring system for the quantitation of T-2 toxin and should be useful for studies on production of this toxin in culture. Specific information on less toxic trichothecenes, however, requires a more time-consuming chemical analysis.