White vs. Light
Albacore, which is the only tuna species that can be called "white," is packed almost exclusively in water in solid form. The source of most light meat tuna is Skipjack and is usually found in a chunk form.
Solid vs. Chunk
Solid, also called "fancy" is a solid portion of a loin, cut to fit the can, and packed in one layer. Chunk is a mixture of cut pieces of varying sizes.
Americans eat about 1 billion pounds of canned and pouched tuna annually. But how does all of this fish get from the ocean to your kitchen?
After the tuna is caught, canned and pouched tuna go through a detailed processing procedure designed to preserve and enhance flavor and to ensure product safety.
Here’s how it works:
Because they are typically caught far off-shore, tuna are usually delivered to canneries frozen or refrigerated.
Upon delivery, processing workers conduct an initial quality control inspection. They make sure the fish were stored at the proper temperature and are in good condition. The tuna are maintained at temperatures ranging from 0° Celsius to -18 °C until processing.
Also, before any tuna are processed, a sample from each load of fish is test-packed and evaluated before and after canning to assess quality. These samples are used to determine whether or not all of the remaining fish in each load are acceptable for processing.
Now that they’ve determined that tuna are in good condition and are ready to be processed, the fish in cold storage are thawed so that they can be more easily handled and cut.
Trained staff inspects and personally evaluate each tuna for quality. Any fish that doesn’t meet quality standards is discarded. The fish that pass inspection are cut into thick blocks called loins.
In what’s called ‘pre-cooking’, the tuna loins are then placed on racks and transferred to large ovens where it is cooked.
Once cooked, tuna is then cleaned of all skin and bones.
Now, packaging takes place. Cleaned cuts of tuna meat are fed into filling machines where product packages (either cans or pouches) are filled with pre-set amounts.
Now, these packages are ready to be sealed. Filled packages are moved to sealing machines where they are closed and sealed. Each package is affixed with a permanent production code that identifies plant, product, date packed, batch and other information. To ensure product safety, the seals of the packages are checked frequently throughout the canning or pouching process to make sure that they are safe and secure.
Filled and sealed packages are then cooked again – this time under pressure using time and temperature schedules designed by processing experts to make the product commercially sterile. This is why tuna is ready to eat right out of the can or pouch and has a long shelf life.
Samples of each finished product receive one last quality control inspection by workers paying close attention to attributes such as color, odor, flavor, texture and cleaning before being released for labeling.
Finally, finished, quality controlled products go to labeling lines where they are labeled and put into cases for shipment. Cased products are marked with information so that they can be tracked during shipment and distribution.