Monascus spp. used in wheat kernel solid-state fermentations: growth, extrolite production and citrinin cytotoxicity

Abstract

Monascus fermentation products can be consumed as food or feed supplements or used as food colouring or flavouring agents. In this study, qPCR and Q-TOF LC/MS methods were developed to monitor Monascus ruber and Monascus purpureus growth and extrolite (lovastatin, mevastatin, as well as the regulated mycotoxin, citrinin (CIT)) production, respectively. Wheat kernels were inoculated with one strain of each species during a solid-state fermentation followed over 63 days. Different growth and extrolite production patterns were clearly observed for the 2 tested strains. After 63 days, high lovastatin levels (up to 0.5 mg/g) were reached for M. ruber wheat fermented kernels while M. purpureus only yielded 0.1 mg/g of lovastatin at best, suggesting that M. ruber may be a better candidate for lovastatin production in a wheat-based model. Mevastatin levels were low and stable for both species. However, M. ruber fermented wheat kernels also contained the highest CIT content, up to 4.2 μg/g, i.e. at levels above the regulation threshold set by the European Union. CIT toxicity was then determined in vitro on bovine kidney cells, showing an IC10 of 6.10-4 M. At maximum concentrations encountered during solid-state fermentation, CIT toxicity was very low under chronic exposure.

Occurrence, Risk Implications, Prevention and Control of CIT in Monascus Cheese: A Review

“…CIT was found at a concentration of up to 4.2 g/g, far exceeding the regulatory level of 2 μg/g established by the European Union (EU) when Monascus ruber is used for fermentation with wheat kernels as a solid substrate. 58 Thirty-seven red yeast rice dietary supplements, including pure red yeast rice, were purchased from the Internet and local Italian pharmacies for CIT analysis by Laura Righetti et al 59 They discovered that approximately 86% of the samples did not satisfy the maximum EU level for CIT and that several items labeled as CIT-free presented CIT contamination. Of the 31 commercial ingredients of red yeast rice supplements purchased in China, Avula et al found CIT in approximately one-third of the samples using liquid chromatography-accurate quadrupole time-of-flight mass spectrometry.…”

“…Recently, human health and intake safety have received increasing attention, and the control of functional products in various countries has increased, alleviating CIT contamination in red yeast rice dietary supplements. CIT was found at a concentration of up to 4.2 g/g, far exceeding the regulatory level of 2 μg/g established by the European Union (EU) when Monascus ruber is used for fermentation with wheat kernels as a solid substrate . Thirty-seven red yeast rice dietary supplements, including pure red yeast rice, were purchased from the Internet and local Italian pharmacies for CIT analysis by Laura Righetti et al They discovered that approximately 86% of the samples did not satisfy the maximum EU level for CIT and that several items labeled as CIT-free presented CIT contamination.…”