Food can sometimes contain odors not normally associated with that food. These odors are called off-flavors, and cow milk is known to contain off-flavors such as hexanal depending on the feed or physical condition of the cows. We previously discovered and revealed the structure of 2-Iodo-4-methylphenol (2I4MP), an off-flavor component in commercially available cow milk. We were the first group to discover 2I4MP is an off-flavor component in cow milk.This study investigated the following three questions. First, what compounds serve as the starting materials in generating 2I4MP? Organic synthesis techniques were used to identify p-cresol as a candidate starting material. Second, how is 2I4MP generated in the cowshed? Using cow dung, we confirmed that 2I4MP was generated by the effects of iodine on cow dung. Based on these findings, measures were proposed to prevent contamination of cow milk by 2I4MP. Third, how is 2I4MP transferred to raw milk? 2I4MP movement was estimated by creating a desiccator-based model that showed 2I4MP is potentially transferred to raw milk in the cowshed. These involve that the iodine-based disinfectants, used to disinfect teats during milking, should not be used excessively. Furthermore, ensuring the disinfectants do not fall onto cow dung or bedding. Adopting these measures is vital for preventing contamination of cow milk by 2I4MP.
Keywords: 2-Iodo-4-methylphenol; commercial milk; cow dung; cow house; off-flavor; p-cresol; raw milk.