CCTV exposed the “shrimp ice coat”, consumers finally found that the “excessive packaging” is not only festival gifts, but also seafood. Then we might as well smash the thick ice with science and see what’s going on here. How to put on the shrimp ice coat? The fresh prawns of


should be protected with ice water mixture to prevent spoilage caused by rising temperature. After they are sent to the processing plant, they are quickly sorted according to the size of the shrimp, such as picking out the ends and tails to make shrimps. Then quick freezing is carried out. In the freezing room, the strong wind is used to blow hard, and the vibrator should be turned on to prevent the shrimp from being frozen together. This process is called “single quick freezing” or

Here comes the key step of

. Deep frozen shrimp is dipped in 0-3 degree water for a few seconds, and then it is taken out and drained for a few seconds. The thin layer of water on the surface will be frozen by the low-temperature shrimp body. This is the “ice coat”. In fact, you can also try the “ice coat” when thawing meat at home. Under normal conditions, the factory will repeat the operation three times to make the thickness of ice meet the process requirements. At this time, the weight of ice accounts for 15-20% of the total weight. Then there is the weighing and packaging process.

2. What is the function of shrimp ice coat?


may have four functions. First of all, the most important thing for quick-frozen food is to keep low temperature. The ice coating of shrimp is equivalent to adding a buffer layer, and the fluctuation of external temperature will be partially offset by the ice layer. Second, the ice layer is isolated from the air, which is the protective layer of shrimp, which can reduce the occurrence of oxidation. It also blocks all kinds of pathogenic microorganisms and further improves the safety of food. Some processing techniques also add some reducing agents to the ice to help the shrimp maintain its bright color, such as vitamin C. Third, the ice layer will also protect the water in the shrimp, playing a water retention role. Ice will also “volatilize” in the frozen state. The scientific term is “sublimation”. Therefore, it is necessary to defrost the refrigerator freezer. In common sense, there is a saying that “put wet books into the freezer for dehydration and recovery”. Seafood itself generally has high water content. If there is no ice package, it will dehydrate after a long time of freezing, and the taste will become worse. Finally, the solid ice layer can also protect the shrimp from damage during transportation, especially the head, tail and foot of shrimp. Of course, if it’s frozen shrimps, frozen scallops or something, there won’t be such a problem.

3. What proportion of shrimp ice coat should be used?


media reports also said that the ice content of frozen cooked prawns in the world is usually 15-20% of the net weight. The industrial standard for frozen cooked prawns issued by the Ministry of agriculture in the first half of the year also requires that the amount of ice should not exceed 20%. This amount of ice is mainly considered in terms of process performance and cost, which is safe and reasonable. But the amount of ice reported in the news and what we see in our daily life has already exceeded the amount of ice required by the process. Some products can achieve 80% ice, obviously for other purposes. Why use overweight ice? The price of


seafood products is relatively high, and the lack of market consumption capacity is the most important reason. When you go to the supermarket to buy quick-frozen seafood, two kinds of the same frozen shrimp are sold, one is sold at 20kg, and the other is sold at 18kg. The salesman will tell you “it’s actually the same”. Which one will you buy? Chinese consumers who pursue cost performance will probably buy the 18 catties, right? The cheap 2 yuan is probably because it is covered with a little more ice, which may not be obvious to the naked eye.


turned out to be 18 catties sold well, while 20 catties were not watched. Then the production of 20 kg of course not convinced, who will pack ice clothes, I pack a little more, sell 17 kg, angry you! Under the dual pressure of “consumers’ endless pursuit of low price” and “currency devaluation, cost rise”, it is inevitable that bad currency drives out good currency.


in order to make quick-frozen seafood still at the “ordinary people’s price” to win the favor of consumers, I’m afraid that the only way to go is to mix water. The more ice in shrimp bags, the lower the cost, the easier to gain competitive advantage. If the same price, the higher the profit. That’s why the shrimp’s ice coat is getting thicker and thicker.


is a double-edged sword for consumers. As the saying goes, “what you buy doesn’t sell well” and “you get what you pay for”. If you don’t want to pay for the cost of good food, the future of “day by day” of food safety can only be a bubble.

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