Toxicological evaluation of a fungal-derived natural colorant using Caenorhabditis elegans: implications for food safety

Abstract

The growing demand for natural colorants as an alternative to synthetic dyes has raised the need for robust safety assessments to support their regulatory approval and safe use in food products. This study evaluated the toxicological profile of a novel azaphilone pigment produced by Talaromyces amestolkiae using Caenorhabditis elegans as a validated in vivo alternative model. Synchronized L1-stage nematodes were exposed for 72 h to azaphilone-contaminated Escherichia coli at concentrations ranging from 3.1 to 50%. Toxicological endpoints included body length, motility, intra-uterine egg count, reproductive performance, larval lethality, and lifespan. Exposure to the colorant led to significant increases in worm length and motility, induced larval lethality, and reduced lifespan at the lowest concentration tested. No mortality was observed, but the effects were sufficient to preclude the identification of a No Observed Adverse Effect Level (NOAEL). A Low Observed Adverse Effect Level (LOAEL) was established below 3.1%. The presence of glucose (1.54 g/100 mL) in the extract may have contributed to some of the observed effects, reflecting the need for improved production processes. The concentrations tested exceeded typical food-use levels. The present study provides important preliminary data to guide future risk assessments. In conclusion, our findings demonstrate that while the azaphilone pigment from Talaromyces amestolkiae shows biological activity at high concentrations, its safety at realistic dietary exposure levels warrants further investigation.