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  • Mycotoxins, residues, contamination


    Mycotoxins are caused by contamination by some naturally occurring moulds. Not every type of mould produces mycotoxins. Mycotoxins are 'selective' in the sense that a given type of mycotoxin occurs in specific foodstuffs: aflatoxins in peanuts, grains and milk; patulin in apple juice; ochratoxin A (OTA) in grains, grapes and derived products, beans and pulses, cocoa, coffee and others. For coffee OTA is the most relevant mycotoxin, but in the framework of an HACCP system it is recommended to envisage measures for mycotoxins in general.

    NB: Information on mycotoxins has been drawn from industry experts, from the findings of the ICO-FAO project 'The enhancement of coffee quality by prevention of mould growth', and the book Coffee Futures published by CABI Commodities (2001).

    The initial contamination of coffee with OTA takes place through spores in the air and in the ground. These spores may produce a mould but only if the right circumstances (humidity and temperature) prevail. The importance of proper moisture management throughout the entire processing and supply chain cannot be overemphasized. Farmers, middlemen and exporters should also be aware that in a shipment of coffee OTA contamination (mould) may be very localized, making sampling extremely complex. Careful inspection of visual appearance and any mouldy or earthy smells can be a useful tool for checking.

    Pesticide residues in coffee have only very rarely exceed the limit values so far, but this does not mean that their monitoring is not a vital aspect of an HACCP system. It is absolutely essential that coffee growers maintain chemical registers that detail, in chronological order, the type and quantities of all chemicals used and the timing of their application. Obviously only chemicals that have been approved for use on coffee may be used and then only within the withholding limits specified by the manufacturers. Exporters and shipping lines must ensure only clean containers are used, thus avoiding cross-contamination by previous cargoes. Go to www.fao.org and search for the Draft Code of Hygienic Practice for the Transport of Foodstuffs in Bulk and Semi-packed Foodstuffs of the Codex Alimentarius Commission.

    Hydrocarbon contamination is usually caused by jute coffee bags because of the 'batching oil' used to soften the jute fibres before spinning. There have been instances of contaminated oil being used (old engine oil for example).

    The International Jute Organization has established specifications (IJO Standard 98/01) for the manufacture of jute bags to be used in the food industry:

    • Analytical criteria. Ingredients used as batching oils must be non-toxic and approved for use in packaging materials that will come into contact with food. Batching oils must not contain compounds that could produce off-flavours or off-tastes in food packed in jute or sisal bags.
    • Chemical criteria. The amount of unsaponifiable compounds (which cannot be converted into soap by boiling with alkali) shall be less than 1250 mg/kg. The method described in British Standard 3845:1990 is recommended for the determination of the added oil content of jute yarn, rove and fabric. Method 2.401 of the International Union of Pure and Applied Chemistry (IUPAC) is recommended for determining unsaponifiable matter.
    • Organoleptic criteria. Jute bags shall be analysed for their olfactory qualities. No undesirable odours, or odour untypical of jute, shall be present. No unacceptable odours shall develop after artificial ageing of the sacks. The ageing procedure to be followed shall be the one described in European Standard EN 766 for use on sacks for the transport of food.

    To read the EU Packaging and Packaging Waste Directive (PPWD) go to http://www.eur-lex.eu and search for Directive 62 of 1994 (94/62/EC).

    Organizations and private companies in India and Bangladesh have developed a hydrocarbon-free lubricant, based on vegetable oil, to soften the jute fibre. It is a non-toxic, biodegradable oil, and bags made with it can be classified as food grade bags. However, the fact that vegetable oil is used for batching is in itself not sufficient: the oil used must be stable and may not turn rancid.