Mycotoxins sampling

United States Food and Dmg Administration (2007b) Sample schedule 6—Mycotoxin sample sizes. In Inspection operations manual 2007. United States Department of Health and Human Services, Food and Dmg Administration, Office of Regulatory Affairs (http // www.fda.gov/ora/inspect ref/iom/ChapterText/sschedule6.html). 

Mycotoxins, toxic metaboUtes of some fungi, can be assayed by immunochemical techniques to determine concentration in animal feed and foodstuffs. Some of the analytes assayed in kits and the detection limits are Hsted in Table 4 (45). These assays are especially advantageous for routine analysis of large samples of foodstuffs (45,46). 

Many natural products are charged substances, and can be isolated by IEC methods. Dufresne has published a comprehensive review describing various resins and column operating conditions applicable to purification of natural products from fermentation broths or crude extracts.168 Among natural products, antibiotics are of special interest due to their widespread use in humans and animals. Sample cleanup by IEC prior to analysis by other LC methods for quantitative determination of antibiotics in biological fluids is frequent.I69171 Also, IEC followed by TLC appears useful for the quantitation of fumonisin Bl, a mycotoxin found in agricultural products.172... 

Surveys of mycotoxin contamination levels in organic and conventional crops often give conflicting results and will therefore not be described in detail here. They often poorly describe the management history of samples included in the survey and may therefore be misleading with respect to the causes of differential mycotoxin loads. Also, the contribution made by primary production practices/factors and storage conditions to overall mycotoxin loads were unclear for most of these studies. 

A case in which the toxin or appropriate metabolite is detected in urine, serum, or plasma, or detection of the specific toxin in environmental samples unless there could be a local source of the toxin (e.g., the molds that produce mycotoxins have been found in some residential and industrial settings, and the toxins have been implicated in some cases of "sick building" syndrome). 

Because estrogenic mycotoxins usually occur at microgram per kilogram (pg/kg) levels there is special interest in analytical procedures for reliable detection of zearalenone and its metabolites between 10 and 100 pg/kg. In response to the risk of a great economic loss to the industry and the threat to human health as a result of exposure to zearalenone, several methods have been developed for the quantification of zearalenone and its metabolites in different foods, feeds, animal tissues, blood and urine. Detailed reviews have been given by Steyn et al. 1991 Betina 1993 Frisvad and Thrane 1993 Scott 1993 Steyn 1995 and Lawrence and Scott 2000. The determination of zearalenone in cereals can be divided into five steps grinding of the sample, extraction of the sample, clean-up, separation and detection. 

Krska R (1998) Performance of modern sample preparation technique in the analysis of Fusarium mycotoxins in cereals. J Chromatogr A 815 49-57 Krska R, Josephs R (2001) The state-of-the-art in the analysis of estrogenic mycotoxins in cereals. J Anal Chem 369 469-476... 

Some microorganisms are also able to transform trichothecenes into less toxic compounds. For example, rumenal bacteria, bacteria from the large intestine of chickens, and bacterial populations from soil samples, were capable of transforming deoxynivalenol into 3-acetyldeoxynivalenol or 3-keto-4-deoxynivalenol (Binder et ah, 2000 Swanson et ah, 1987 He et ah, 1993 Shima et ah, 1997). Therefore, it seems likely that the development of wheat crops with the capability of eliminating this mycotoxin or bio-treatments could possibly be developed as a feasible strategy. 

Park, D.L., Njapau, H. and Coker, R.D., Sampling programs for mycotoxins perspectives and recommendations, in Miraglia, M., van Egmond, H.P., Brera C. and Gilbert, J., eds., Mycotoxins and Phycotoxins Developments in Chemistry, Toxicology and Food Safety, Alaken Inc, Colorado, 1998. 

SPR systems also showed encouraging results with their ability to detect mycotoxins. The BIACORE was used to detect a mycotoxin, DON, produced by Fusarium species, from spiked wheat sample in a competitive inhibition assay (Schnerr et ah, 2002). Biotinylated DON was immobilized on the sensor chip which was previously coated with strep-tavidin. Mycotoxin extracts from wheat samples were first allowed to react with the antibody and then injected into the BIACORE. The detection range was established to be 0.13-10 pg/ml. In a slightly modified format, DON was also detected by SPR at a range of 2.5-30 ng/ml (Tudos et ah, 2003). 

With the currently available systems for PCR-based detection and identification, however, qualitative information about the presence or absence of a certain fimgus can be obtained and this should be used to advantage in food and feed quality control because the technology has the power to provide insights into the mycotoxigenic potential of analyzed samples. This information can then be used in order to decide whether samples should proceed down the process of production or should be retained for further analysis of mycotoxins. PCR-based multiplex systems... 

Starodub NF, Pylipenko LN, Egorova AV et al (2008) Analysis of mycotoxins preparations of samples. Biotechnology 1 106-115... 

Berlath, M., Backes, F., Kramer, J. 1998. Mould spectrum and mycotoxins (Deoxynivalenol and Ochratoxin A) in grain samples from ecological and integrated cultivated sites. Agribiological Research 51 369-376. 

Tests for mycotoxin contamination can be accomplished both on the finished product and on the raw form. The latter case prevents the manufacture of an unfit product, but it often implies trouble in the evaluation of the contamination in a batch. In this case, for a defined sample size, sample preparation, and analytical method, principles are available to evaluate the accuracy of the aflatoxin determination, depending on the availability of an accurate estimate of the variability associated with each step of the analytical sequence (11,12). A valuable effort to estimate the uncertainty of the analytical sequence as a whole was carried out by the FAO (13). 

The uneven distribution of mycotoxins in grain has so far been statistically defined only for aflatoxins in a few matrices (corn, cottonseed, peanuts) (15,16), and sampling plans have been developed worldwide almost entirely for these toxins. 

Analyzing control materials alongside the test samples greatly improves proficiency in mycotoxin analysis. Certified reference materials (CRMs) represent ideal control materials, due to their statement of uncertainty and traceability, and they should be routinely used as much as possible. Unfortunately, as outstanding as the improvements made in the last decade have been, even though the list of CRMs in the area of mycotoxins is rather long, it is still insufficient. A list of the available reference materials in the mycotoxins area is reported in Table 1 the issue has been reviewed by Boenke (27). 

Mycotoxins are toxic secondary metabolites produced by fungi growing within or on foods. They can be a serious threat to human and animal health (Nagler el al., 2001). Table 11.4 details mycotoxins associated with soft drinks and fruit juice manufacture and raw materials. Patulin is the most common mycotoxin associated with fruit juice, particular ly apple juice (Pitt Hocking, 1997). It commonly occurs if juice is produced from stored apples. Mould growth in infected apples increases with time, raising levels of patulin. The use of windfall apples for juice is also a factor. Avoidance of windfall apples, filtration of juice and pressing quickly after harvest are all methods to reduce the incidence of patulin in juice. Patulin can be destroyed by fermentation to cider or by the addition of ascorbic acid (Marth, 1992). Within Europe, the European Union has set a limit of 50 ig/kg for patulin in both apple juice and cider. A recent survey of apple products in Chile found that 28% of samples of juice and concentrate exceeded this limit (Canas Aranda, 1996). 

This paper shows a nice example for solving an important analytical problem using MISPE. Mycotoxins and particularly zearalenone (ZON) and /nmv-a-zearalenol (a-ZOL) present an everyday problem in food analysis. Existing sample clean-up techniques have different drawbacks. Liquid-liquid extraction is characterized by... 

Although MIPs can overcome these problems, no appropriate MIPs had been developed before, due to the high cost and the toxicity of these mycotoxins. The authors succeeded in synthesizing a good ZON mimicking template and made with it an MIP of suitable binding characteristics. This MIP has been applied for the analysis of cereal and swine feed samples. 

Kalinoski et al. [32] has applied this method to the determination of tri-chothecene mycotoxins in wheat. The methods were based on chemical ionisation MS and collision-induced dissociation tandem MS and enabled the rapid identification of ppm levels of several trichothecene mycotoxins. Supercritical carbon dioxide is shown to allow identification of mycotoxins with minimum sample handling in complex natural matrices such as wheat. Tandem MS techniques are employed for unambiguous identification of compounds of varying polarity, and false positives from isobaric compounds are avoided. Capillary column SCFC-MS of a SCF extract of the same sample was also performed, and detection limits in the ppb range appear feasible. 

Disbold et al. [34] developed a laser fluorimetric method for the determination of zearalenone (6-(10-hydroxy-6-oxo-fra s-l-undcccnyl-/i-resorcylic acid n-lactone))-infected corn. By combining laser fluorimetry with high-pressure liquid chromatography, these workers were able to detect and quantitate the naturally fluorescent mycotoxin zearalenone in contaminated corn samples. 

Various other workers have reviewed the sample preparation and preservation [35] and analytical determination of [36-38] mycotoxins in cereals and Inhat [39] and Beaver [41] have reviewed gas chromatographic methods for the determination of mycotoxins. 

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