IAFP 2009 Program Book and Abstract Book - AB137

P2-90 Immuno Assay-based Test for the Detection and Quantitation of Soy Protein Contamination of Food Commodities MOHAMED M. ABOUZIED, Michael E. Sarzynski and Stephen L. Taylor Neogen Corporation, R & D, Lansing, MI, USA Introduction: Allergy to soy proteins is a food allergy that accounts for about 3% of allergies in the American population. Purpose: Develop an immunoassay-based test that can be used in the food industry to monitor soy protein contaminations in incoming ingredients or in the final product. Methods: A 30-min Soy Protein Allergen Test for quantitative analysis of soy protein contamination in food products and incoming raw ingredients was developed. The test is a Sandwich Enzyme-Linked Immunosorbent assay (S-ELISA). Polyclonal and monoclonal antibodies against specific soy protein markers were used as the capture and detector antibodies. For quantitative analyses, a standard curve of soy protein isolate (SPI) ranging from 0 to 100 PPM (0 to 4 µg ml) was used. Samples were extracted by shaking 5 g of ground samples with 125 ml of PBS in a hot water bath. Extracts were filtered and filtrates were used directly for ELISA analyses. Extracts are added to antibody-coated wells in which soy proteins bind to the capture antibody during a 10-min incubation period. Any unbound protein is washed away and antisoy horseradish peroxidase-labeled antibody (detector antibody) is added. The detector antibody binds to the soy protein during a 10-min incubation period. Unbound enzyme-labeled antibody is washed away and a one step substrate is added. Color develops as a result of the presence of bound-labeled antibody during a final 10-min incubation period. Absorbance readings of samples are compared with those of the standards and the concentrations in parts per million (PPM) are calculated. Results: Mean recovery of soy protein isolate (SPI) from various spiked samples was found to be 87%. Limit of detection was found to be less than 10 PPM (0.4 µg/ml) determined as soy protein isolate (SPI). The test is capable of detecting residue contamination of all sorts of soy products such as soy flour, soy protein isolate, soy protein concentrate, soy textured proteins and most soy processed products. No cross-reactivity was observed with any other plant or animal proteins such as tree nuts, grains, legumes, pork, beef or chicken meats. Significance: The test can detect microgram quantities of soy contamination in different commodities such as milk, juice, salad dressing, meat products, ice cream and bakery products. P2-91 A Sensitive, Rapid ELISA Test for the Detection and Quantitation of T-2 and HT-2 Toxins in Grain Commodities MOHAMED M. ABOUZIED and Aaron M. Walsh Neogen Corporation, Lansing, MI, USA Introduction: T-2 toxin and HT-2 toxin are potent toxins belonging to the group trichothecenes type A mycotoxins that are usually produced by fungi of the Fusarium genus, which are commonly found in various cereal crops (wheat, corn, barley, oats, and rye) and processed grains (malt, beer and bread). T-2-and HT-2 toxins often occur together in infected cereals. They elicit a severe inflammatory reaction in humans and animals and have teratogenic effects. Purpose: To develop an easy to use, accurate analytical method to detect and quantitate the two toxins in grain commodities. Methods: A polyclonal antibody-based Enzyme Linked Immunosorbent Assay (ELISA) for the detection and quantification of T-2 and HT-2 toxins in agriculture commodities was developed. The assay is a direct competitive ELISA in a micro-well format. Results: The detection limit of the assay is less than 1 ng/ml (less than 10 ppb) of individual T-2 and HT-2 or a mix of both mycotoxins. The test can detect T-2 or HT-2 at 100% of either or a mixture of them in corn, wheat, barley , rye and oats. Concentration of T-2 or HT-2 required for 50% binding inhibition is 6.8 ng/ml (68 ppb). The antibody used is very specific for T-2 and HT-2. The antibody has no cross reactivity with other trichothecenes such as T2-tetraol deoxynivalenol (DON), 3-acetyl-DON, 15-acetyl-DON, and, fusarenon-x, zearalenone or nivalenol. Samples were extracted by shaking 5 g ground sample with 25 ml of 70% methanol-water (1:5) for 3 min. Extracts were diluted 1:1 with water and then used in the ELISA test. The mean recovery of T-2, HT-2 or a mixture of both in corn, wheat, barley and oats determined by this method was 87%. Significance: The assay can be used to quantify T-2/HT-2 in samples within 10 min. P2-92 Comparative Study of the Soleris™ Yeast and Mold Test System and Direct Plating for Semi-quantitative Determination of Yeast and Mold in Foods Susan Alles, Nabina Shrestha, Amanda Ellsworth, Alicia Rider, Debra Foti, JAKE KNICKERBOCKER and Mark A. Mozola Neogen Corporation, Lansing, MI, USA Introduction: The Soleris Yeast and Mold test system is an automated, growth-based method with an optical endpoint. A portion of test sample homogenate is added to the Soleris vial containing a selective growth medium. Products of yeast and mold metabolism cause a color change in an indicator chemical, and this change is detected by the instrument over time. Threshold test sensitivity is determined by the volume and dilution of sample homogenate added to the Soleris test vial. The test may be applied at a single threshold to yield a positive or negative result, or two or more dilutions may be tested to generate a semi-quantitative result. Results are available in 72 hours or less. Purpose: The purpose of this study was to compare performance of the Soleris method to that of the FDA/BAM direct plating method for determination of yeast and mold levels in 10 food products. Inclusivity and exclusivity characteristics of the method were also assessed in pure culture testing. Abstract Book — 137 Poster

IAFP 2009 Program Book and Abstract Book

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