Q: What is the difference between CO treated tuna and ULT tuna?
A: CO tuna has been chemically treated with carbon monoxide to change the tuna to a red color and to keep it looking red regardless of its quality. It will not change colors even if the quality has already deteriorated. ULT tuna is an all natural product frozen at Ultra Low Temperatures to help it retain its real sashimi quality. A ULT tuna product is a high value, high quality product and will turn colors only when its quality has deteriorated, just like fresh tuna, so the consumer will never be deceived.