and unlike their dull beige outer appearance, when broken open they are a translucent deep ruby color inside. Rarely, very high-end honkarebushi repeat this drying process for over two years. In the Edo era, it was common for katsuobushi to go through an extra step, the so-called process. After the fillets are boiled and their rib bones removed the fish are put in steaming baskets stacked atop one another for one to two hours a few meters above a burning wood fire. These are rotated to assure an equal exposure to the smoke. The result is more flavorful and resistant to deterioration. Due to the extra cost and facilities required only a few factories following tebiyama-shiki remain. Shaving Traditionally, chunks of katsuobushi were shaved as needed with an instrument similar to a wood plane called a katsuobushi kezuriki. Today katsuobushi is typically sold in bags of small pink-brown shavings, which vary by thickness: smaller, thinner shavings, called hanakatsuo (), are used as a flavoring and topping for many Japanese dishes, such as okonomiyaki, while the larger thicker, called kezurikatsuo (), are favored for making the widely used dashi stock. Uses In addition to making dashi, other popular uses of katsuobushi include: Okaka, finely chopped katsuobushi dressed with soy sauce. As a stuffing for rice balls (onigiri). As a topping for rice. Popular for bentō, often covered with strips of laver. Dried okaka is used as an ingredient of furikake rice topping (called "okaka furikake"). As a seasoning for cold tofu (hiyayakko, ) along with grated ginger and Welsh onion (a type of spring onion). Sprinkled with sesame seeds and chopped laver atop cold soba noodles (zarusoba). As a topping on takoyaki and okonomiyaki. As a seasoning on preserved egg along with sesame oil and soy sauce. As a high-protein treat for cats sold at pet stores. As a topping for ramen mixed with salt. Health The mycotoxin beta-nitropropionic acid has been found on katsuobushi as well as in miso and in soy sauce, two other Japanese fungal fermented products. Certain strains of A. glaucus are reported to produce mycotoxins. Due to the smoking process which involves tar and charcoal, amounts of benzopyrene exceeding EU standards, as much as 37μg per kilogram, have been detected in commercially sold katsuobushi. As a result, they have been once banned for sale in the European Union. See also List of dried foods Maldive fish