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This study reports the fungal and bacterial metabolites associated with natural contamination of 38 composite samples of locally processed rice from five Agro-ecological Zones of Nigeria (AEZs). The samples were evaluated for the presence of microbial metabolites with the Liquid Tandem Mass Spectrometry (LC-MS/MS) technique. Among the identified metabolites, 63 fungal and 5 bacterial metabolites were measured at varying concentrations and occurrence levels. Fusarium toxins had the highest incidence of 79% but occurred in low amounts with fumonisin B1 (FB1) having the highest percentage incidence of 39.5% and a mean of 18.52 µg/kg. Among the Aspergillus toxins, aflatoxins (AFs) occurred in 36.9% of the rice samples with aflatoxin B1 (AFB1) having the highest occurrence level of 18.4% and a mean value of 5 µg/kg. About 12 metabolites had incidence levels >50%, including beauvericin (BEA) and tryptophol which had occurrence levels of 100%. Among the emerging toxins under evaluation by international organizations such as the European Food Safety Authority (EFSA) and the Food and Agriculture Organization of the United Nations (FAO), citrinin, sterigmatocystin (STER) and beauvericin were detected with maximum values of 207, 125 and 131 ?g/kg respectively. This paper also reports the first documented evidence of the contamination of Nigerian rice by bacterial and Alternaria metabolites, nivalenol, kojic acid, STER, moniliformin, fusaric acid, fumonisin B3, citrinin, 3-nitropropionic acid, andrastin A, cytochalasins, emodin and physicon.

Phytochemical, antioxidant and antimicrobial properties of n-butanol, petroleum ether and ethanol extracts of the leaf of Chrysophyllumalbidum were investigated. Antioxidant activity was carried out using various tests which include; 2, 2-diphenyl-picrylhydrazyl (DPPH) scavenging activity, total antioxidant activity, ferric reducing antioxidant power (FRAP), total flavonoid content and the total phenolic content. The antimicrobial test was conducted on the following micro-organisms; Salmonella dysenteriae, Bacillus cereus, Salmonella typhi, Acinetobacter spp., Escherichia coli, Klebsiellapneumoniae, Penicillum spp., Aspergillusflavus, Fusariumverticoides, Aspergillus tamari and Aspergillusparasiticus using the agar well diffusion method. Results revealed that petroleum ether gave the highest extract yield (16.8%) while butanolic extract had the least yield (4.6%). At 250 µg/ml extract concentration, petroleum ether extract demonstrated the highest (73.57%) DPPH scavenging activity followed by ethanol extract (59.32%) while butanolic extract had the least scavenging activity of 32.02%, and these were significantly different (P

This study reports the distribution of fungal isolates and fungal metabolites that naturally contaminate locally processed rice from five agro-ecological zones of Nigeria. The fungal species were isolated by the dilution plate technique and identified by appropriate diagnostics, while metabolites were determined by a liquid chromatographic tandem mass spectrometric method. Aspergillus and Penicillium species were the predominant isolates found in the rice samples while Fusarium spp. were not isolated. The mean fungal count differed significantly (p

The antimicrobial effect of Corn Steep Liquor (CSL) was investigated over a five day period. The pH and titrable acidity of the liquor were determined, while the antimicrobial effect on some diarrhoea causing organisms such as Escherichia coli, Salmonella enteriditis, Staphylococcus aureus and Vibrio parahaemolyticus was also determined. Using well diffusion method, 0.1 ml (100 μl) of the liquor effectively inhibited the growth of the test organisms with zones of inhibition ranging from 4.00 ± 0.28 to 20.20 ± 0.14 mm. The zones of inhibition increased with increasing number of days of fermentation of the filtrate on which is the CSL. However, there was no significant difference (P>0.05) in the antimicrobial properties of the liquor on day 3 and 4 for S. enteriditis, S. aureus and V. parahaemolyticus. The zone of inhibition on day 5 was significantly different (P