[Effect of Cooking and Processing on Quantitation of Soybean Proteins].

We examined the effects of cooking and processing on the quantitation of soy protein in various soy-based foods. For the phosphate-buffered saline (PBS) extraction, the total protein content was measured by bicinchoninic acid assay, and the buffer extraction containing sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (ME) was measured by the 2-D Quant Kit, and SDS-polyacrylamide gel electrophoresis analysis (SDS-PAGE) of each extraction was performed. Furthermore, measurements were performed by various ELISAs.

[Detection of allergenic substances (shrimp, crab) in processed seafood].

We have carried out a study (2009-2012) on processed seafood products in order to determine the level of contamination with shrimp and crab. In 2010-2012, after the Allergy Labeling Regulation went into effect, the detection rate of crustacean protein in processed seafood products including small fish, such as niboshi, tukudani and so on (both boiled and dried), was 63%. Detection rates for processed seafood products in which crustacean protein levels were below 1 μg/g were 36% with and 58% without advisory labels, allowing us to conclude that 60% of labels were adequate.

[Comparison between old and new methods for detection of allergenic substances (egg and milk)].

The old ELISA method for detection of allergenic substances (egg and milk) in Kanagawa prefecture from 2003 to 2007, employed before improvement of the food allergen labeling system, yielded detection rates of 20% for egg and 30% for milk. In 2005, after improvement of the labeling system, the detection rate using the new ELISA in solutions containing 1% SDS and 7% 2-mercaptoethanol increased by about 10% for egg, but decreased by half for milk. There were 4 positive samples (over 10 µg/g) for both egg and milk proteins, on account of contamination by ingredients at the manufacturing line and the lack of proper food labeling.