In Europe wheat, barley and maize are significant components in food and feed processing. Fusarium moulds (e.g. Fusarium moniliforme) have become a serious problem because they produce a range of toxic metabolites (mycotoxins) which endanger the health of both humans and animals. Fusarium mycotoxins such as fumonisins cause animal diseases such as leukoencephalomalacia and porcine pulmonary oedema and may also induce liver cancer on experimental rats. The high levels of fumonisins (FB1 & FB2) occurring in maize intended for human consumption have been associated with human oesophageal cancer. Commercial maize-based foodstuffs obtained from single random purchases from retail outlets such as samples of extruded maize, maize flour, and polenta showed about 852% positive samples in 1995 with levels >1 mg/kg a level of concern for human health. In France, lower incidences were found, i.e. <50% positive samples. Levels of around 60 mg/kg of FB1 and 15 mg/kg of FB2.
The overall objectives of this project are to examine systems of pre-harvest crop treatment, and post-harvest control to remove contaminants and prevent fungal development in food. It will provide biological and chemical means of detoxifying mycotoxins. This should also help identify the feasibility and the critical points where corrective measures can have a controlling effect for prevention of the entry of these mycotoxins into the food chain. The best combinations of treatments in the chain will be identified by the HACCP approach. The commercial exploitation of the technologies will be examined in collaboration with end users. This trans-European consortium includes partners in UK, Finland, Holland, Spain and Italy.
The six key objectives to control and prevent contamination of food with Fusarium species and their mycotoxins are:
- Development of critical control systems: Use of ecological and control data for developing a Hazard Analysis Critical Control Point (HACCP) system for identification, reduction and prevention of the risk of Fusarium mycotoxins entering the food chain.
- Preharvest Biocontrol: Development of biocompetitive strains for preharvest control and competitive exclusion of toxigenic fusaria, in cereal (wheat/barley/oats/maize) production.
- Post-harvest control: Novel natural control food-grade systems will be used for control of mycotoxigenic species and the reduction of chemical inputs into food.
- Decontamination using microbial inoculants for prevention of entry into animal production systems: Bacteria and yeasts will be used for the breakdown of mycotoxins in stored cereals
- Decontamination using physical means. Adsorbent materials and biomarkers will be used to assess the exposure to Fusarium mycotoxins (i.e. sphinganine/sphingasine ratio for fumonisins) to quantify the effectiveness of treatments.
Good progress has been made during the first reporting period of the project. Studies have determined in vitro discrimination between different bacteria, yeasts and filamentous fungi using simulated media for bread, cakes and cheese. These studies have generally been successful with discrimination being possible within 48-72 hrs of growth. The differentiation of different concentrations, e.g. 102, 104, 106 CFUs, has been successful for some species but not all. However, it was noted that different groups of sensors in the different e.nose systems being used might be optimal for different spoilage microorganisms. A review of off-taints of different food types has been carried out and key volatile markers for these and for microbial spoilage have been determined. Studies using GC-MS and bread analogues inoculated with spoilage fungi have also enabled confirmation of key volatile compounds responsible for spoilage. Studies on grain and flour to detect spoilage moulds were compared using different e.nose systems. Studies showed that using one of the tested systems (Gas Detector, MGD-1-S) was mainly differentiating samples based on humidity and not on the presence of Fusarium in barley.