europe has banned imports of japanese katsuobushi. that's because of the way they've infused and built flavor. the burning of the fish to do that creates carcinogens or cancer-causing substances. the japanese fisheries ministry says its research shows the amount is minuscule. it also says they're not water soluble so the health risks are said to be small enough to overlook. despite some of the concerns, one producer says many chefs are looking f forward to using the ingredient. >> translator: they told us as soon as it's available, they'll use it. the boom in popularity of japanese food is pushing the need for dashi stock and ka t. >> reporter: one month after the completion of the factory in france, it's producing katsuobushi that meets the world food safety regulations. by using a different machine from the traditional one, french manufacturers can avoid contaminating the product. but the modified technique doesn't produce a flavor that meets japanese taste. >> translator: we don't want to be considered a lower quality prododuct tha