Optical biosensor for the detection of hydrogen peroxide in milk

Milk is one of the most complete foods for humans, containing nutrients including carbohydrates, proteins, fats, minerals, and vitamins [1]. Owing to its rich composition, milk becomes a substrate for the growth of undesirable microorganisms that can easily deteriorate milk. To prevent this from happening, prohibited substances are fraudulently added [2]. One of those substances is hydrogen peroxide (H2O2), which is widely used in the dairy industry as an antimicrobial agent, thus helping preserve the raw milk in the absence of refrigeration [3]. Despite its conventional use, when added to milk, H2O2 solution can cause a decrease in the nutritional value of the food, due to the destruction of vitamins A and E, which generates reactive and cytotoxic oxygen species, including hydroxyl radicals, that can initiate oxidation and damage nucleic acids, lipids and proteins. By consequence, when ingested, milk can lead to negative effects on the health of the population, especially in individuals immunocompromised persons [2][3]. Here, it is presented a study for the detection and quantification of H2O2 using a chemiluminescence technique. A small low-cost hydroxyethyl cellulose sensitive membrane combined with a high-sensitive photodetector is used to measure H2O2 concentrations from raw to ultra-pasteurized milk samples.