Dual-color blending based visual LAMP for food allergen detection: A strategy with enlarged color variation range and contrast

•A near contrast color change was obtained by blending HNB and CR colorimetric LAMP detection process.•The sensitivity of the dual-color blending method was comparable to the real-time LAMP.•The ratio between the two visual dyes in the dual-color blending method is crucial.•The reaction is conducted in one tube and no lid-opening was needed.