Mentaiko is a popular Japanese delicacy made from salted cod roe, typically seasoned with spices and sometimes chili. It is often enjoyed as a topping for rice, pasta, or as a filling in sushi. The dish has its origins in Korea, where a similar product called myeongnanjeot is made. In Japan, mentaiko is commonly found in Fukuoka, where it is a regional specialty. It is usually sold in jars or vacuum-sealed packages and can be eaten raw or cooked. The unique flavor and texture make it a favorite among many food enthusiasts.