Effect of wheat species (Triticum aestivum vs T. spelta), farming system (organic vs conventional) and flour type (wholegrain vs white) on composition of wheat flour - Results of a retail survey in the UK and Germany - 3. Pesticide residue content.

Wheat is a major component of the Northern European diet and contributes significantly to dietary pesticide exposure. Here we report results of a 2-year retail survey, which compared pesticide residues in organic and conventional, whole-grain and white, common and Spelt wheat flour brands available in the UK and Germany. Pesticide residues were detected significantly more frequently in conventional (87%) than organic (25%) flour samples. Chlormequat, a plant growth regulator, was the most frequently detected compound. Total concentrations of pesticide residues were (a) ~4 times higher in conventional than organic, (b) ~100% higher in common than Spelt wheat flour and (c) ~110% higher in conventional whole-grain than white flour samples, but (d) not significantly different in organic whole-grain and white flour. Results suggest that the use of organic wheat products allows increased whole-grain cereal consumption in line with nutritional recommendations, without an increase in dietary pesticide intake.

Effect of wheat species (Triticum aestivum vs T. spelta), farming system (organic vs conventional) and flour type (wholegrain vs white) on composition of wheat flour; results of a retail survey in the UK and Germany - 1. Mycotoxin content.

Wheat is one of the main dietary sources for mycotoxins that can cause adverse health effects in humans. Here we report results of a 3-year survey which compared the effects of flour type (whole-grain vs white), wheat species (common vs spelt), and farming system (organic vs conventional) on mycotoxin concentrations in UK and German wheat flour brands. Wholegrain, conventional and organic flour contained 124, 31 and 9% higher concentrations of T-2/HT-2, DON and ZEA respectively, but concentrations of the three Fusarium mycotoxins assessed were ~10 times lower than the EC-maximum contamination levels (MCL). Thirty one percent of flour samples had Ochratoxin A (OTA) concentrations above the MCL (3 µg/kg), but OTA levels were no affected by wheat species, farming system and flour type. Results suggest that both organic and conventional primary production methods and postharvest quality assurance systems are effective for maintaining Fusarium mycotoxins, but not OTA concentrations, below the MCL.

Effect of wheat species (Triticum aestivum vs T. spelta), farming system (organic vs conventional) and flour type (wholegrain vs white) on composition of wheat flour - Results of a retail survey in the UK and Germany - 2. Antioxidant activity, and phenolic and mineral content.

There is strong evidence for health benefits from whole-grain wheat consumption and these have been linked to their higher fibre, antioxidant/(poly)phenolic and mineral contents. However, there is still scientific controversy about the relative effect of wheat species (Triticum aestivum vs T. spelta) and production methods (conventional vs organic) on the nutritional composition of wheat. The retail survey reported here showed that, the use of spelt varieties and organic production results in significantly higher (between 10 and 64%) levels of phenolics and some minerals in wheat flour. However, the relative effect of removing the outer bran and germ during milling was substantially larger; levels of antioxidant activity, and many phenolic compounds and mineral nutrients were 2-5 times higher in whole-grain than white flour. Organic flour contained higher concentrations of the undesirable metals Al and Ni (12% and 81% respectively), and spelt flour had 28% higher concentrations of the toxic metal Cd.