Israeli startup Allerguard is developing a handheld device that scans and analyzes vapors from prepared food to determine the presence of allergens (e.g. peanuts). Electrochemical sensors detect non-safe molecular levels of allergens using three technologies. Allerguard has just raised $1.5 million of funds.
https://www.calcalistech.com/ctech/articles/0,7340,L-3771525,00.html