Design of prototype device for killing anisakid larvae using pulsed power technology
Chinari Onitsuka1,2, Kengo Nakamura2, Douyan Wang3, Mikiya Matsuda4, Akihiko Ogasawara3, Ritsuo Tanaka3, Yoichi Inoue2, Masayoshi Kouduma5, Kenji Negoro6, Takayasu Negoro6, Takao Namihira3, *
* The author to whom correspondence should be addressed.
1 Graduate School of Science and Technology, Kumamoto University, Japan
2 Japan Seafoods Co. Ltd., Japan
3 Institute of Industrial Nanomaterials, Kumamoto University, Japan
4 Technical Division, Kumamoto University, Japan
5 Maycraft, Japan
6 Pultec Electronics Co., Ltd., Japan
Abstract
Anisakid nematode larvae are found in fish and cephalopods and can cause anisakiasis in humans when raw or undercooked seafood is consumed. An estimated 20,000 cases of anisakiasis occur annually in Japan. The only practical way to kill anisakis apart from heating has been freezing, but freezing can damage the texture and color of the fish meat. As an alternative to freezing, we have shown that anisakis in fish can be killed through the repeated application of pulsed high current through the fish meat, and that the quality of pulse-treated fish meat is almost the same as that of untreated meat. The following includes a description of a prototype device used to kill anisakid larvae using pulsed power technology. High temperatures can adversely affect fish meat quality. In order to apply the pulsed current while keeping the temperature of the fish meat as low as possible, we created a treatment tank filled with 180 liters of buffer saltwater, placed the fish meat between plane-to-plane electrodes in the treatment tank, and applied pulsed current while using pumps to agitate the water. Parameters such as saltwater conductivity, charging voltage, and capacitance necessary for killing anisakid larvae were studied using Taguchi methods, and the performance of the device was analyzed. To ensure worker safety, all parts of the device that may be touched by workers were grounded. The device was installed at a seafood processing factory where tests were conducted showing that all test larvae were killed. Currently, the company sells horse mackerel fillets treated with this device to some of its customers, and it is highly regarded for its safety and low impact on meat quality.
Keywords - Anisakis, Anisakid larvae, parasite, pulsed current, pulsed power.