For the last several months I have been taking you through the general processing steps for tuna starting from thawing to cooling. I have always emphasized the importance of having a system of accurate control and temperature monitoring. This will result in excellent quality, and maximum recoveries/yields. This article will take you through the steps of skinning and cleaning the cooked tuna in preparation for canning or frozen loins.

Once the cooked tuna has been properly cooled to the correct temperature range, it should be staged for skinning. The temperature range can be from ambient to a maximum of 100F. It is best to skin the tuna when it has reached an ambient temperature so that the muscle tissue has firmed up and also when the skin is still moist. Skinning hot fish will make it more difficult and will create the loin to break and create much flake as the fish is still soft and hard to handle.

Skinning is normally done with a dull stainless steel knife with a blunt tip. These knives can be a simple butter knife or a clamming knife which is more popular in the USA. There are also knives that are specifically made for cleaning tuna which can be purchased in the USA or Asia. The objective is to remove all of the skin without taking off the meat. The knife is used to scrape the skin until it is completely removed. Any dark spot or bruise is also removed. There are several techniques that are more effective than others but all methods will work. After all of the skin is removed, it is now ready for cleaning.

Cleaning consists of removing the loins from the bones, and also removing the blood meat. This can be done on the same table or on a different table or location. When you clean at different tables or stations, this is called 2 stage cleaning. If it is done by the same person at the same table and station, then it is called single stage cleaning. The 2 stage is more popular as it results in a cleaner loin and less flake. The technique and knife is very important as it will result in a better cleaned loin with less flake. The flake is normally a downgraded product which will result in a lesser product with lower value. It is important to minimize flake to reduce your loss. It is also important that the all the flake and pieces of meat are removed and not disposed of in the scrap. This must be minimized in order to have acceptable recoveries. The recovery will have a direct impact on your profitability so it is important to assure that you are maximizing it.

The cleaned tuna will consist of 4 loins that are smooth and not have defects, bones, bruises, or discoloration. There will also be some pieces and flake also without any defects as stated previously. This tuna is now ready for canning or vacuum sealing. You should always remember to monitor the temperature and time that the tuna is staged and during skinning/cleaning to assure prevention of decomposition. It is recommended that you set specific times and temperature range that you allow before it is deemed unacceptable. By following these general guidelines it will result in having a good acceptable product that you will be satisfied with.

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