At least one hospital in Japan serves meals containing a high concentration of diethyl hexyl phthalate, a substance believed to adversely affect the reproductive systems of animals, a group of researchers announced Friday.
Researchers at the National Institute of Health Sciences suspect the source of the contamination is gloves used by kitchen staff.
The gloves, made from vinyl chloride, contain a large volume of DEHP and other hormone-disrupting substances.
The findings were reported by the researchers at a Tokyo meeting of the Food Hygienic Society of Japan.
A group of companies involved in the manufacture and sale of the gloves said the products are not harmful to human health, adding, however, that they have decided to create DEHP-free products.
The researchers said they detected 4 micrograms of DEHP per 1 gram of food in both of the two meals served at one of three hospitals they surveyed. One microgram is one-millionth of a gram.
DEHP, a kind of phthalate ester, is widely used in Japan to make plastics, such as vinyl chloride, softer.
More than 300,000 tons of DEHP are produced annually in Japan.
However, experiments using animals show that DEHP reduces sperm production.
Another group of NIHS researchers said they detected between 280 mg and 380 mg of DEHP in 1 gram of each of three different types of glove made from vinyl chloride.
Their findings also revealed that the gloves are affected by contact with rape-seed cooking oil.
Large amounts of hormone-disrupting substances are released five minutes after vinyl chloride gloves were put in oil at a temperature of 95 C and after 10 minutes when the oil is at 60 C, the researchers said.
DEHP is released from the gloves even within 30 seconds of being placed in oil and even at a temperature of 5 C, they said.