Migration of styrene dimers and trimers from polystyrene containers into instant foods

Abstract

The migration of styrene dimers and trimers from polystyrene containers into instant foods and their content in the container were determined by GC and GC/MS. Thirty-two kinds of instant foods, which included Chinese noodles, Japanese noodles (udon), buckwheat noodles (soba), chow mein (yakisoba), spaghetti, soup (miso-soup, minestrone, etc.) and rice (gomokumeshi, chuka- don and gruel) were analyzed. In the whole instant foods, the migration levels of the total trimers ranged from undetectable to 62.4 ng/g (0-33.8 μg/cup) while dimers were not found. In the case of Chinese noodles, the migration into noodles was higher than that into soup and the total migration level at 30 minutes after adding hot water was 1.5 times higher than that at 10 minutes. In the case of Chinese noodles and soup in EPS (expandable polystyrene) containers, the contents of dimers and trimers in the material of the containers were under 800 μg/g, and they did not detect in the foods. Raw or non-fried noodles had a lower migration level than fried noodles even in PSP (polystyrene paper) cups which contained more than 4,800 μg/g of dimers and trimers. The migration during microwave oven cooking was somewhat higher than during hot-water cooking.