Identification of fungal and bacterial contaminants on flour

Abstract

Flour is the main ingredient used in the production of bakery products. Environmental factors such as humidity and storage temperature promote the growth of ubiquitous fungi and bacteria on such products, leading to spoilage, reducing shelf life and thus negatively impacting the food economic sector. Moreover, certain fungal species produce mycotoxins: substances that may cause severe harm to humans and animals. Bacterial species which contaminate flour products include pathogenic and disease-causing agents. Microbiological contamination can take place during cultivation, harvesting, formulation, processing, packaging, and storage. Fungal and bacterial microbiological contamination in food products is a global concern and the demand for better quality food products is on the rise. This project aimed to tackle this problem by identifying the common organisms which contaminate flour obtained from both local sources as well as foreign countries. Culturable and molecular methods were used to identify the fungal and bacterial pathogens to the genus and species level. The results indicated that the fungal pathogens on the flour samples consisted of Penicillium spp., Cladosporium spp., Aspergillus spp., and Alternaria spp. amongst others. The fungal microbiome was further investigated through the use of Next Generation Sequencing (NGS) which further highlighted the fungal biodiversity. The fungal organisms which have been identified are also known to cause contamination due the pre- and post-harvesting phase. In terms of the bacterial microbiome, organisms such as Pantoea spp., Bacillus spp, Pseudomonas spp., and Peribacillus spp. amongst others were identified through Matrix-Assisted Laser Desorption/Ionized Time Of Flight Mass Spectrometry (MALDI-TOF MS).