BivalvesSome of the popular IQF-bivalves products include vacuum-packed half shell oysters, clams, cockles, and scallops, which are also availables as coated products or as ingredients in complete ready-made meals. Which slow freezing of oysters causes darkening of the muscle and drip formation, the problem is reduced by quick freezing. Molluskan shellfish such as oysters, clams, and myssels are fil-ter feeders and accumulate microorgrams and other particulate matter in the gut from the surrounding water. The important preprocessing step for bivalves is depuration. In depuration, the sellfish are stored in tanks of potable water usually for 36-48 h and allowed to decontaminate naturally. Specially-made depuration plants with attached recirculating seawaters systems are available for t he purpose. In a process for IQF mussel, the animals are declumped, precleaned, and transferred to a rewatering station for 8-12 h for depuration. The samples are then cooked at 95°C for about 30 sec. The cooking process opens the shells and the meat is removed by shucking over vibrating graders. Cooking also ensures adequate inac-tivation of viruses such as small round viruses, which are associated with coastal sewage pollution and food poisoning. The “beard”, a tough, inedible anchor muscle is removed from the meal after shucking. The cooked meat is weighed and filled in a bag, in many cases containing some sauce. The bags are vacuum-sealed, cooked in a suitable cooker, cooled and frozen at -18°C, and stored at this temperatune. The product has a shelf life of 2 years. A process for retaining taste and also for reducing bacteria in frozen oyster has been patented. In the process, the top shell of the oyster is initially removed, followed by rapidly lowering the tempeature of used for freezing or canning. Frozen shelf of clam is limited to 4 or 6 monts at -18°C due to development of rancidity and toughening. Cryogenic freezing prevents these deteriorative changes. Scallops are marketed either as frozen in blocks with plate or as IQF without breading.
đang được dịch, vui lòng đợi..
