Measuring Mold Infestation in Raw Tomato Juice

Authors


  • The authors are grateful to Jennifer Payne, EuniceTan, Paula Chou, Ryan Hammond, and Johnie Young in the Biological and Ag. Engineering Department at the University of California at Davis for their assistance in conducting this study. We also thank the California Processing Tomato Advisory Board for the support they provided.

Abstract

A modified fluorescent lectin test for molded raw tomato juice was compared with both the visual mold inspection method conducted by the California Processing Tomato Advisory Board and the Howard mold count (HMC) conducted by 4 commercial tomato processors. The assay quantifies fungal contamination by detecting fungal chitin using FITC-labeled lectin that selectively binds to chitin. The mold content of 100 naturally infected raw tomato juice samples was determined using these 3 methods. The coefficient of determination between the lectin assay and the HMC (r2= 0.73) was better than the coefficient of determination between the California processing tomato visual mold inspection method and the HMC (r2= 0.38). The coefficient of determination between the fluorescent lectin assay and the HMC (r2= 0.73) was comparable to the coefficient of determination between different quality control laboratories' HMC values, which ranged from r2= 0.69 to r2= 0.81. The fluorescent lectin assay had consistently better precision (average CV = 8%) than the HMC (average CV = 38%).

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