Occurrence of regulated mycotoxins and other microbial metabolites in dried cassava products from Nigeria

Open Access JournalDried cassava products are perceived as one of the potential sources of mycotoxin ingestion in human foods. Processing either contributes to the reduction of toxins or further exposes products to contamination by microorganisms that release metabolic toxins into the products. Thus, the prevalence of microbial metabolites in 373 processed cassava products was investigated in Nigeria. With the use of liquid chromatography tandem-mass spectrometry (LC-MS/MS) for the constituent analysis, a few major mycotoxins (aflatoxin B1 and G1, fumonisin B1 and B2, and zearalenone) regulated in food crops by the Commission of the European Union were found at concentrations which are toxicologically acceptable in many other crops. Some bioactive compounds were detected at low concentrations in the cassava products. Therefore, the exposure of cassava consumers in Nigeria to regulated mycotoxins was estimated to be minimal. The results provide useful information regarding the probable safety of cassava products in Nigeri

Efficacy of metabolites of a Streptomyces strain (AS1) to control growth and mycotoxin production by Penicillium verrucosum, Fusarium verticillioides and Aspergillus fumigatus in culture

The objectives of this study were to determine the efficacy of metabolites of a Streptomyces strain AS1 on (a) spore germination, (b) mycelial growth, (c) control of mycotoxins produced by Penicillium verrucosum (ochratoxin A, OTA), Fusarium verticillioides (fumonisins, FUMs) and Aspergillus fumigatus (gliotoxin) and (d) identify the predominant metabolites involved in control. Initial screening showed that the Streptomyces AS1 strain was able to inhibit the mycelial growth of the three species at a distance, due to the release of secondary metabolites. A macroscopic screening system showed that the overall Index of Dominance against all three toxigenic fungi was inhibition at a distance. Subsequent studies showed that the metabolite mixture from the Streptomyces AS1 strain was very effective at inhibiting conidial germination of P. verrucosum, but less so against conidia of A. fumigatus and F. verticillioides. The efficacy was confirmed in studies on a conducive semi-solid YES medium in BioScreen C assays. Using the BioScreen C and the criteria of Time to Detection (TTD) at an OD = 0.1 showed good efficacy against P. verrucosum when treated with the Streptomyces AS1 extract at 0.95 and 0.99 water activity (aw) when compared to the other two species tested, indicating good efficacy. The effective dose for 50% control of growth (ED50) at 0.95 and 0.99 aw were approx. 0.005 ng/ml and 0.15 μg/ml, respectively, with the minimum inhibitory concentration (MIC) at both aw levels requiring > 40 μg/ml. In addition, OTA production was completely inhibited by 2.5 μg/ml AS1 extract at both aw levels in the in vitro assays. Ten metabolites were identified with four of these being predominant in concentrations > 2 μg/g dry weight biomass. These were identified as valinomycin, cyclo(L-Pro-L-Tyr), cyclo(L-Pro-L-Val) and brevianamide F

Portable infrared laser spectroscopy for on-site mycotoxin analysis

Mycotoxins are toxic secondary metabolites of fungi that spoil food, and severely impact human health (e.g., causing cancer). Therefore, the rapid determination of mycotoxin contamination including deoxynivalenol and aflatoxin B(1) in food and feed samples is of prime interest for commodity importers and processors. While chromatography-based techniques are well established in laboratory environments, only very few (i.e., mostly immunochemical) techniques exist enabling direct on-site analysis for traders and manufacturers. In this study, we present MYCOSPEC - an innovative approach for spectroscopic mycotoxin contamination analysis at EU regulatory limits for the first time utilizing mid-infrared tunable quantum cascade laser (QCL) spectroscopy. This analysis technique facilitates on-site mycotoxin analysis by combining QCL technology with GaAs/AlGaAs thin-film waveguides. Multivariate data mining strategies (i.e., principal component analysis) enabled the classification of deoxynivalenol-contaminated maize and wheat samples, and of aflatoxin B(1) affected peanuts at EU regulatory limits of 1250 μg kg(−1) and 8 μg kg(−1), respectively

Evaluation of emerging Fusarium mycotoxins beauvericin, enniatins, fusaproliferin and moniliformin in domestic rice in Iran

The occurrence of emerging Fusarium mycotoxins beauvericin (BEA), enniatins (ENNs) (A, A1, B, B1), Fusaproliferin and moniliformin was evaluated by a liquid chromatography/ electrospray ionization-tandem mass spectrometric (LC/ESI-MS/MS) technique in 65 domestic rice samples produced in Gilan and Mazandaran Provinces in Iran. The results showed that 46 of the samples were contaminated with at least one of the emerging mycotoxins. BEA was the most prevalent mycotoxin, which was found in 26 out of 65 rice samples at the concentrations up to 0.47 µg/Kg. Enniatin A1 which was the only member of ENNs was detected in the samples, occurred in 7.7 of samples with an average level of 0.06 μg/Kg. No detectable level of Fusaproliferin and moniliformin was found. This is the first report concerning the contamination of Iranian domestic rice samples with the emerging Fusarium mycotoxins. © 2015 by School of Pharmac

Analysis of Mycotoxin and Secondary Metabolites in Commercial and Traditional Slovak Cheese Samples

Cheese represents a dairy product extremely inclined to fungal growth and mycotoxin production. The growth of fungi belonging to Aspergillus, Penicillium, Fusarium, Claviceps, Alternaria, and Trichoderma genera in or on cheese leads to undesirable changes able to affect the quality of the final products. In the present investigation, a total of 68 types of commercial and traditional Slovak cheeses were analyzed to investigate the occurrence of fungal metabolites. Altogether, 13 fungal metabolites were identified and quantified. Aflatoxin M1, the only mycotoxin regulated in milk and dairy products, was not detected in any case. However, the presence of metabolites that have never been reported in cheeses, such as tryptophol at a maximum concentration level from 13.4 to 7930 µg/kg (average: 490 µg/kg), was recorded. Out of all detected metabolites, enniatin B represents the most frequently detected mycotoxin (0.06–0.71 µg/kg) in the analyzed samples. Attention is drawn to the lack of data on mycotoxins’ origin from Slovak cheeses; in fact, this is the first reported investigation. Our results indicate the presence of fungal mycotoxin contamination for which maximum permissible levels are not established, highlighting the importance of monitoring the source and producers of contamination in order to protect consumers’ health

Detection of Endophyte Mycotoxins by Service Laboratories: Providing Answers for Safe Feed

. A global network of service laboratories exists to test livestock feed materials (typically grass hay and pellets) for ergovaline, ergot alkaloids and lolitrem B to ensure ‘safe feeds’ are being given to livestock. These compounds are mycotoxins produced by endophytic fungi that naturally reside in feed material. They have been purposely bred into grass species, as they enhance the plant’s survival from drought and insect predation. Unfortunately, ergovaline and other ergot alkaloids also cause vasoconstrictive effects and reproductive difficulties in livestock, resulting in a $1 million annual loss in production for the cattle industry in the USA alone. Lolitrem B is a neurotoxicant that causes a syndrome known as ‘ryegrass staggers,’ which involves a tremoring response in the animal. Clients of these service laboratories include hay farmers who want to be confident that the product they are selling is safe to feed to livestock; veterinarians who are trying to rule out causes of disease in clinical cases; individuals wanting to check personal feed sources; and researchers investigating innovative solutions to these feed contaminants. Each year, approximately 33,000 containers of hay are shipped overseas from the USA, including Pacific Rim and Middle Eastern countries, bringing in an estimated$130 million annually. If the importing country requires it, the material in these containers must be tested for the appropriate mycotoxin(s) and have a certificate stating that the level found was below the established threshold of toxicity. Discussion of sample submission, analysis and result receipt will be compared amongst international laboratories known to perform analyses for these mycotoxins

Rapid, simple and cost-effective molecular method to differentiate the temperature sensitive (ts+) MS-H vaccine strain and wild-type Mycoplasma synoviae isolates

Mycoplasma synoviae infection in chickens and turkeys can cause respiratory disease, infectious synovitis and eggshell apex abnormality; thus it is an economically important pathogen. Control of M . synoviae infection comprises eradication, medication or vaccina- tion. The differentiation of the temperature sensitive (ts + ) MS-H vaccine strain from field iso- lates is crucial during vaccination programs. Melt-curve and agarose gel based mismatch amplification mutation assays (MAMA) are provided in the present study to distinguish between the ts + MS-H vaccine strain, its non-temperature sensitive re-isolates and wild- type M . synoviae isolates based on the single nucleotide polymorphisms at nt367 and nt629 of the obg gene. The two melt-MAMAs and the two agarose-MAMAs clearly distinguish the ts + MS-H vaccine strain genotype from its non-temperature sensitive re-isolate genotype and wild-type M . synoviae isolate genotype, and no cross-reactions with other Mycoplasma species infecting birds occur. The sensitivity of the melt-MAMAs and agarose-MAMAs was 10 3 and 10 4 copy numbers, respectively. The assays can be performed directly on clinical samples and they can be run simultaneously at the same annealing temperature. The assays can be performed in laboratories with limited facilities, using basic real-time PCR machine or conventional thermocycler coupled with agarose gel electrophoresis. The advantages of the described assays compared with previously used methods are simplicity, sufficient sensitivity, time and cost effectiveness and specificity