Mycotoxins are secondary metabolites of molds that have adverse effects on humans, animals, and crops that result in illnesses and economic losses. The worldwide contamination of foods and feeds with mycotoxins is a significant problem. Aflatoxins, ochratoxins, trichothecenes, zearalenone, fumonisins, tremorgenic toxins, and ergot alkaloids are the mycotoxins of greatest agro-economic importance. Some molds are capable of producing more than one mycotoxin and some mycotoxins are produced by more than one fungal species. Often more than one mycotoxin is found on a contaminated substrate. Mycotoxins occur more frequently in areas with a hot and humid climate, favourable for the growth of molds, they can also be found in temperate zones. Exposure to mycotoxins is mostly by ingestion, but also occurs by the dermal and inhalation routes. The diseases caused by exposure to mycotoxins are known as mycotoxicoses. However, mycotoxicoses often remain unrecognized by medical professionals, except when large numbers of people are involved. Factors influencing the presence of mycotoxins in foods or feeds include environmental conditions related to storage that can be controlled. Other extrinsic factors such as climate or intrinsic factors such as fungal strain specificity, strain variation, and instability of toxigenic properties are more difficult to control. Mycotoxins have various acute and chronic effects on humans and animals (especially monogastrics) depending on species and susceptibility of an animal within a species. Ruminants have, however, generally been more resistant to the adverse effects of mycotoxins. This is because the rumen microbiota is capable of degrading mycotoxins. The economic impact of mycotoxins include loss of human and animal life, increased health care and veterinary care costs, reduced livestock production, disposal of contaminated foods and feeds, and investment in research and applications to reduce severity of the mycotoxin problem. Although efforts have continued internationally to set guidelines to control mycotoxins, practical measures have not been adequately implemented.

ABSTRACT

The effect of engine oil on microbial dynamics in an aquatic environment was investigated. Water samples was polluted in aquaria with crude oil at different concentration 0%, 1%, 2%, 3%, 4%. Sampling was taken from the polluted water at the interval of three days for analysis. Bacteria isolated from water samples gotten from Ntak Inyang River before and after pollution includes Staphylococcusaureus, Citrobacter sp and Chromobacter sp. Fungal isolates were Penicillium sp, Aspergillumsniger, Aspergillus flavus and Rhizopus sp. The total heterotrophic bacteria count(THBC) of the water sample before pollution ranged from 2.5×105cfu/ml to 3.0×105cfu/ml while that of total fungal count(TFC) ranged from 3.1×104cfu/ml and 3.3×104cfu/ml. After 18 days of incubation, bacterial counts increased to 3.7×105cfu/ml while fungal count reduced to 3.5×104cfu/ml. The engine oil utilizing microorganisms showed increase in growth as the concentration increased. This provides useful information for the bioremediation of polluted aquatic environments.

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