[Study for Formation Root of Off-Flavor Substance 2-Iodo-4-methylphenol in Milk].

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.

[Identification and Quantification of 2-Iodo-4-methylphenol in Milk].

It is well-known that a strange flavor, known as off-flavor, might be found in various food products. Even though these substances do not affect our body directly, they can cause a significant change in food flavor and smell, thereby lowering the quality of food products. A well-known example of off-flavor is the transfer of smell from one food product to another. We have previously studied how the smell of limonene, a flavor component of orange juice in paper cartons, is transferred from unopened packages to milk stored in paper cartons, and have confirmed cases where the milk develops a smell completely different from that of limonene. This smell was also confirmed to not have originated from orange juice, and was found to be similar to that of a halogenated phenol. This study aimed to identify this odor component, and our findings indicate the off-flavor component to be 2-iodo-4-methylphenol.