Manychemicalcontaminantsareformedduringthecombustionoffuelbothinthe smoking and in the direct drying process. Examples include polycyclic aromatic hydrocarbons (PAH), dioxins, formaldehyde, nitrogen and sulphur oxides (relevant for formation of e.g. nitrosamines). Furthermore, heavy metals are also found in combustion gases. The types and amount of contaminants depend on the fuel used, the temperature and possible other parameters.
2. Hundreds of individual PAH may be formed and released as a result of incomplete combustion or pyrolysis of organic matter, during forest fires and volcanic eruptions as well as industrial processes or other human activities, including the processing and preparation of food. Owing to their mode of formation, PAH are ubiquitous in the environment and therefore enter the food chain, especially via air and soil. PAH can be present in the raw materials due to environmental contamination from the air by deposition on crops, from contaminated soils and transfer from water to fresh and marine invertebrates. Commercial and domestic food preparation such as smoking, drying, roasting, baking, barbecuing or frying are recognized as important sources of food contamination. Presence of PAH in vegetable oils can also originate from smoking and drying processes used to dry oil seeds prior to oil extraction.
3. Contamination of food with PAH via environmental contamination should be controlled either by source-directed measures like filtering the smoke from relevant industries (e.g. cement work, incinerator and metallurgy) and limiting the exhaust fumes of PAH from cars. Good practices, including the selection of appropriate farmland/fishing waters, could also decrease the environmental contamination of raw materials with PAH. However, this contribution to the reduction of PAH intake from the final food is not included in this Code of Practice.
4. Processes such as smoking and direct drying provide a wide variety of food textures and flavours and consequently a broader choice for consumers. Many types of smoked and dried foods are traditional food items, where these types of
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Adopted 2009. Revised 2009.
PREVENTION AND REDUCTION OF FOOD AND FEED CONTAMINATION (1st Edition)
processes have been used to prolong the storage period, keep quality and provide flavour and consistency required by consumers. The extension of shelf life may also have an effect on the nutritional value of foodstuffs, such as preservation of the vitamin content.
5. The major contributors to intakes of PAH are cereals and cereal products (owing to high consumption in the diets) and vegetable fats and oils (owing to higher concentrations of PAH in this food group). Generally, despite their usually higher concentration of PAH, smoked fish and meats and barbecued foods do not contribute significantly, particularly as they are small components of the diet. However, they do make larger contributions leading to higher PAH intakes where these foods make up a large part of the diet.
6. In its opinion on PAH, JECFA recommended that efforts should be made to reduce contamination with PAH during drying and smoking processes, e.g. by replacing direct smoking (with smoke developed in the smoking chamber, traditionally in smokehouses) with indirect smoking.