A fluorescent lectin test for mold in raw tomato juice

Fungal (mold) contamination is an important indicator of low quality raw pr oduct in the processing tomato industry. A quantitative lectin assay was de veloped that was less expensive, faster, and more precise than the industry standard Howard mold count. This assay, based on a fluorescent-labeled lec tin isolated from wheat germ, had a selective affinity for the chitin in fu ngal cell walls. Assay values were correlated with mold contamination for 4 fungal species: Alternaria alternata (r(2) = 0.91), Cladosporium herbarum (r(2) = 0.75), Fusarium oxysporum (r(2) = 0.97), and Stemphylium botryosum (r(2) = 0.99). Combining all 3 species, the lectin assay had a strong corre lation (r(2) = 0.76) with a linearized Howard mold count.