I found information about organic milk on news paper.
The milk farm has started to sell organic milk from April. The price of milk is about 20 US dollar/liter. The farm says that they can produce only 20L a day.
Organic farming is not common in Japan. The area for organic farming is only 9,956 ha.
Source (Data of organic agriculture in the world)
I want to try that organic milk but it is too expensive for me to buy…