A study undertaken by scientists at the U.S. FDA has investigated the frequency and levels of soy allergen in packaged bakery and snack food products where no soy allergen was declared on the label or where a soy precautionary statement had been used.
Two widely-used enzyme-linked immunosorbent assay (ELISA) methods were used to analyse representative samples of 558 bakery and snack products. Soy protein was detected in 17% of the products using the commercial Neogen kit and 11% of the products using the commercial Elisa Systems kit. Soy protein was detected more frequently in the bakery products analysed in study than in the snack foods.
Among 284 bakery samples, soy protein was detected in 25% of the samples with no precautionary statement and 19% of the samples which had a precautionary statement. Among 274 snack samples, soy protein was detected in 11% of the samples with no precautionary statement and 9% of the samples which had a precautionary statement.
The study authors report the sample repeatability was at an acceptable level for each method and food commodity, while the reproducibility between kits was 23% for bakery foods and 36% for snack foods. They stress their findings emphasise that suitable detection methodologies and references doses are crucial for labelling accuracy and the safety of soy allergic consumers.
Reference: Khuda et al. 2016. Food Additives & Contaminants. Part A Chemistry, Analysis, Control Exposure & Risk Assessment. Vol. 33(8) pp.1274-82. Doi: 10.1080/19440049.2016.1207809.
Figures relating to the kits used in the study are free access.