Mycotoxins Content of Smoked Fishes Sampled on Market Stalls of Ngaoundere and Antifungal Activity of Essential Oils of Cymbopogon citratus and Ocimum basilicum against Mycotoxin Producing Strains

Abstract

Aim: The aim of this study was to evaluate the sanitary quality of smoked fish by determining their mycotoxin content, and also the chemical composition, antifungal activity of Cymbopogon citratus and Ocimum basilicum essential oils from Cameroon against some mycotoxigenic fungal strains responsible of the smoked fish biodegradation. Place and Duration of Study: Laboratory of Food Microbiology and Biotechnology, National School of Agro-Industrial Sciences, University of Ngaoundere, Cameroon, from August 2019 to April 2020. Methodology: Fifteen samples of smoked fishes have been collected in August 2019 from “petit marché” market (Ngaoundere, Cameroon). Physico-chemical parameters of smoked fishes were evaluated. Mycotoxin (AFB1, CIT, and OTA) contents have been determined with HPLC. Isolation and identification of molds were done using their macroscopic and microscopic characteristics, and the identity of the strains was done by PCR sequencing methods. For plants, 15 kg of Cymbopogon citratus leaves and 5 kg of Ocimum basilicum leaves have been harvested on 10 September 2019 in Ngaoundere and used for the essential oil’s extraction. Essential oil extraction has been done through hydrodistillation and the determination of its chemical composition done with GC/MS. Results: Major part of samples contains at least one mycotoxin, in quantities which are beyond the safe dose. Eleven species of molds have been identified: Aspergillus spp., Penicillium citrinum, and Mucor hiemalis. Amongst the isolated species, those which can produce mycotoxins are: Penicillium citrinum, Aspergillus versicolor, Aspergillus fumigatus, Aspergillus carbonarius, Aspergillus niger, and Fusarium moniliforme. Geranial (42.4%), Neral (33.5%) and Myrcene (10.8%) are major compounds found in the essential oil of C. citratus while monoterpens (60.8%), Eugenol (30.7%), Linalol (29.4%) and 1,8-Cineol (14.3%) are the major compounds found in the essential oil of O. basilicum.  Conclusion: Essential oils of C. citratus and O. basilicum are efficient against isolated toxigenic species. C. citratus being more efficient than O. basilicum.