Genotoxicity, acute, and subchronic toxicity evaluation of dried protein-rich biomass.

Filamentous fungus biomass is a protein-rich food, which can serve as an alternative to animal, plant, and legume protein sources. is a filamentous fungus that typically grows in tropical and sub-tropical regions. Traditionally, has served as a model eukaryotic organism due to its ease of growth and propagation and suitability for genetic manipulation. However, filamentous fungi, such as , have also been consumed or used to produce fermented foods for centuries and have been developed into protein-rich biomass ingredients to be used in conventional foods and meat substitutes. A panel of toxicological tests including genotoxic, acute, and subchronic studies were conducted on dried biomass to support its safe use in food. The dried biomass was found to be not genotoxic in a bacterial reverse mutation (Ames) assay, an in vitro chromosomal aberration test, and an in vivo micronucleus test. In the acute and subchronic toxicity studies, rats were orally gavaged with biomass at concentrations of 0, 1,000, 2,500, and 5,000 mg/kg body weight/day for 14 and 90 days, respectively. At the conclusion of the studies, there were no test article-related toxicity results observed in clinical observations, body weight, food consumption, ophthalmology, hematology, clinical chemistry, coagulation, thyroid hormone, urinalysis, and macroscopic and microscopic findings. The no-observed-adverse-effect level for the dried biomass ingredient was determined to be 5,000 mg/kg body weight/day, the highest dose tested.