Recently, a small video was circulated on the Internet. Two video poisoning cases were mentioned in the video. The poisoning was attributed to the consumption of long-spotted eggs. It was even mentioned that the detection mechanism detected food poisoning in long-spotted eggs. salmonella. For the smooth surface of the eggshell, there will be spots? When the egg grows into a "pock face", is it necessarily related to Salmonella? Does eating long spotted eggs have any effect on health? And see how the experts answer questions.

Good egg is the long spot

"The long-spotted egg mentioned above does not know whether it refers to the stain on the surface of the egg, or does it look darker inside the eggshell and has a dark spot like a watermark?" When interviewed by the Science and Technology Daily, Beijing Huadu Dr. Li Guangqi, the breeding manager of the 峪 禽 poultry industry limited company, said that the first situation is that the surface of the egg has darker spots or bulges, which look like freckles. In fact, only the calcium and eggshell pigments are unevenly distributed. From the perspective of egg formation process, the formation of eggshells and colors is at different stages from the formation of egg contents, and these spots have no effect on the nutritional quality of eggs. In the second case, there are dark spots inside the eggshell. “Reports on dark spotted eggs can be traced back to the 1990s. They have only been widely concerned in recent years and have been studied from different angles, but the specific formation mechanism of dark spotted eggs is still inconclusive.” Li Guangqi explained that research has shown The high temperature and high humidity environment will induce the appearance of dark spots inside the eggshell, but the adverse effects of eggshell dark spots on egg quality have not been discovered. In addition to these two cases, there is also a situation in which the eggs are long-spotted. Zhu Yi, an associate professor at the College of Food Science and Nutritional Engineering at China Agricultural University, said that eggshells are attacked by microorganisms and may also produce spots. “Smooth and dense eggshells have many pores. Bacteria and molds can be drilled in. Generally, the poorer the sanitary conditions of the storage environment and the longer the time, the greater the chance of being invaded by bacteria and mold. The microbes that enter the inner surface of the eggshell, after camping on the inner surface and growing up, form a dark spot visible to the naked eye."

Long spots and Salmonella are not necessarily related

Although the eggshell may be spotted by microbial attack, "the egg long spot is not necessarily related to Salmonella. The spotted egg does not necessarily have Salmonella. Feed, environment, nutrition and other factors are the main factors causing egg spots. Similarly, Eggs infected with Salmonella are not necessarily spotted," said Huang Xiuyingbo, director of veterinary medicine at Beijing Huadu Shoukou Poultry Co., Ltd. So, under what conditions will eggs be infected with Salmonella? In Huang Xiuying's view, when the hen is infected with Salmonella, the bacteria will invade the ovaries, causing follicular degeneration and necrosis, causing Salmonella to be carried in the eggs produced. In the case of hens carrying bacteria, Salmonella will proliferate in the intestines and be excreted in the feces. During the laying of the hens, when the eggs are discharged through the cloaca, Salmonella can also infect the surface of the eggs. The other is environmental pollution. Salmonella has a wide range of hosts in nature, and can be found in mammals, reptiles, birds, insects and human gastrointestinal tracts. The infection rate of a wide variety of domestic and wild animals ranges from 1% to 20%. When the eggs are exposed to contaminated feces, utensils, etc., the eggs will be infected.

Do not wash and store thoroughly.

Zhu Yi suggested that consumers should try to buy fresh eggs. Do not store them for a long time after buying them. Refrigeration should not exceed one month, and room temperature should not exceed half a month. "Eggs are afraid of heat and fear of freezing. It is best to store them in a clean, odor-free place. Fresh eggs can't be washed before storage." Huang Xiuying reminded that Salmonella can grow in the range of 10 °C - 42 °C. However, only a few of them are pathogenic to humans. Ingesting food or beverages contaminated with Salmonella is the only way to infect people. Although Salmonella is more viable in the outside world, the suitable growth temperature is 37 ° C, but Salmonella is not heat resistant. “Completely cooked eggs, that is, the egg center temperature should be at least 75 ° C and maintained for 30 seconds, can effectively kill Salmonella.” Zhu Yi said that the Chinese Dietary Guidelines (2016) also recommended that boiled eggs generally after the water is boiled Continue to cook for 5-6 minutes on a small fire to fully kill the pathogenic bacteria.