While dairy products were not the main pathways for the ingestion of radioiodine in Japan, it is clear that the most important method of limiting thyroid doses, especially to children, is to restrict the consumption of fresh milk from grazing cows.

The estimates of thyroid doses to children following the accident were low. This was the result of a combination of factors, including the time of year (before the growing season), agricultural practices in Japan, low consumption of cows’ milk by infants and the controls on milk consumption that were immediately introduced. These factors contributed to the low level of intake of 131I. This is in contrast to the situation following the Chernobyl accident, where the dominant intake pathway of 131I for children living in contaminated areas was ingestion intake, mainly due to consumption of fresh milk from cows grazing on pasture. People in contaminated areas were not immediately aware of the accident and continued to drink locally produced milk. This resulted in average equivalent dose to the thyroid of up to a few thousand mSv.