Microbial toxin detection

Sophisticated and veiy sensitive methods have been developed in the food industry for detecting many other microbial toxins. For example, aflatoxin deteetion in seedstuffs and their oils is performed by solvent extraction, adsorption onto columns containing selective antibodies for them, and detected by exposure to ultraviolet light. 

Wannemacher, R.W., Jr., Hewetson, J.F., Lemley, P.V. (1991). Comparison of detection of ricin in castor bean extracts by bioassays, immunoassays, and chemical procedures (abstr 030), 10th World Congress on Animal, Plant, and Microbial Toxins, Singapore. 

Microtox can be used effectively for screening of new water supplies, pre- and post-treatment monitoring to evaluate the effectiveness of such treatment and to test waters transported often for long distances under difficult situations to confirm that they remain contamination free. It should be noted that Microtox will detect chemical contamination but will not [Rovide information on microbiological quality unless significant quantities of microbial toxins have been released. 

Several research groups have reported antibodies for aflatoxins and other mycotoxins (27). Commercial kits for aflatoxin detection in various substrates have been announced. The introduction of such kits will permit on-site detection of aflatoxins to be confirmed immediately rather than having to wait for analytical results from a remote laboratory following detection of fluorescing materials in a commodity. Since aflatoxins and other microbial toxins have a number of structural variations, the antibodies used in their analysis must be carefully selected to assure that the proper compounds are being detected and accurately measured. 

In addition, the Biacore system is fully automatic and incorporates a reliable microflnidic system that facilitates accurate and precise sample delivery and flow-rate manipnlation. Significantly, it also permits multichannel analysis and thns, reference-subtraction [71], which is useful for comparative analyses and is a prereqnisite for kinetic and affinity estimations. A significant advantage of SPR over optical detection techniques is that the incident light energy does not actnally penetrate the bnlk sample and thus, measurements can be made equally on colored or tnrbid solntions and on clear samples [72]. Typically Biacore and SPR/evanescent wave-based technologies have been routinely used for analysis of small molecnles. With specific reference to foodstuffs, these include hormones [9], antibiotic residnes [73], and small molecules that are indicative of microbial contamination snch as microbial toxins [10,46,74]. 

Delehanty and Ligler [5] used an antibody microarray system with continuous fluid flow to detect microbial toxins and simultaneously detected both cholera toxin and staphylococcal enterotoxin at a detection level as low as 8 and 4 ng/ml, respectively, within 15 min. Yang et al. [6] developed a device for detecting and genotyping influenza A viruses. Construction of the device utilizes solid-state electronics microfabiicated in silicon and glass, deposition of resistive heaters for thermal... 

Enrichment of microbial toxins including ricin, SEE, andbotulinum neurotoxins (BoNT) has been performed using multiplex-immuno-affinity purification. Specific monoclonal antibodies for each of the four toxins were selected from a pool of antibodies, the selected antibodies allowed for the specific and simultaneous capture of toxins. This assay enabled unambiguous identification of toxins in complex food matriees with a detection limit of 500 fmol. Additionally, it allowed for the rapid differentiation of closely related BoNT sero- and subtypes ((Kull et al. 2010). 

With the extraction procedure we employed (22), ferulic acid was isolated as the most inhibitory component in wheat straw. There could also be other unknown compounds in the straw which would not be evident with this procedure. In addition, we ignored the possible influence of toxin-producing microorganisms. Microorganisms may have influenced the phytotoxicity exhibited by the aqueous wheat extract in Table IX. Although the present study was not concerned with the phytotoxic effects of microbially decomposed wheat straw, an influence of microbial activity on ferulic acid phytotoxicity was observed. From the results shown in Table XI, it appears that the presence of the prickly sida seed carpel enhanced the inhibitory effects of ferulic acid. In addition to ferulic acid in test solutions containing prickly sida seeds with carpels, a second compound, 4-hydroxy-3-methoxy styrene, was also found to be present. This compound is formed by the decarboxylation of ferulic acid and was produced by a bacterium present on the carpel of prickly sida seed. The decarboxylation of ferulic acid was detected in aqueous solutions of ferulic acid inoculated with the bacterium isolated from the carpels of prickly sida seed. No conversion occurred when the bacterium was not present. 

In swine, following intra-aortic administration, the disappearance of parent T-2 toxin followed a two compartment open model with mean elimination phase half-life of 13.8 min and mean apparent specific volume of distribution of0.3661/kg (Beasley et al, 1986). Parent T-2 toxin was not detected in plasma, urine, or liver but was transiently present in lymphoid tissues. T-2 toxin and metabolites were eliminated as glucuronide conjugates into bde, undergoing deconjugation in the intestinal tract by microbial action and then underwent enterohepatic recirculation (Corley et al, 1985). 

The acute bacterial toxins associated with food poisoning episodes are not commonly reported in pharmaceutical products, although aflatoxin-producing aspergilli have been detected in some vegetable ingredients. However, many of the metabolites of microbial deterioration have quite... 

This chapter reviews appUcations of SPR biosensors for detection of chemical and biological contaminants that present environmental risks, including organic chemicals, inorganic chemicals, microbial pathogens, and toxins. 

Therefore, it is necessary to develop strategies to distinguish and quantify fungal infection, and possibly toxins production, at early stages. One of the most promising techniques is the analysis of volatile compounds which are released by the coffee in the headspace gas surrounding the samples. For this reason, the ability of the EOS to early detect microbial contamination of Arabica green coffee was evaluated [36]. 

Kull S, Pauly D, Stormann B, Kirchner S, Stammler M, Domer MB, Lasch P, Naumann D, Domer BG. Multiplex detection of microbial and plant toxins by immunoaffinity enrichment and matrix-assisted laser desorption/ionization mass spectrometry. Anal Chem. 2010 82(7) 2916-24. doi 10.1021/ac902909r. 

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