Eggs, as a must-have ingredient in the kitchen, are cheap, good quality and nutritious.
When buying eggs, we will find that some eggs are clean on the surface, while others are covered with chicken shit. Everyone will naturally avoid those with chicken shit and choose eggs with clean surfaces.
But, are eggs without chicken shit really clean? Not necessarily!
Invisible pathogenic bacteria on eggs
Hens lay eggs and defecation through the "cloaca", and eggs and chicken shit will always meet. Although eggs without chicken shit look clean, they may still carry some dirty things that we cannot see with our naked eyes, which are pathogenic bacteria.
Source: AI Generation
Surveys show that the total number of bacteria on the surface of eggshells reaches about 1.5 million. Although this data sounds scary, you don't have to be too scared. In fact, bacteria exist in the environment. Our human body may also have 10,000 to 1 million colonies per square centimeter, forming a number of bacteria in different units.
What we need to be wary of is the "dirtiest" pathogenic bacteria in eggs - including Staphylococcus aureus, E. coli and Salmonella.
There was once a study to test commercially available eggs in Fangshan District, Haidian District and Shunyi District, Beijing. The results showed that the detection rate of E. coli on egg shells in three regions was relatively high, with an average bacterial rate of 80%; the average bacterial rate of Salmonella was 15%; and the average bacterial rate of Staphylococcus aureus was 5%.
Salmonella and E. coli can be detected with more obvious feces and dirt on the surface of the eggshell, and there are more colonies. Most of the detected ones with cleaner surfaces are E. coli, with fewer colonies.
There was an experiment that specifically studied eggs with salmonella on the surface. Eggs with light surface pollution (eggs that look clean) take a certain amount of time to infect the contents by microorganisms.Often 3 days of storage at 25℃, salmonella can pass through the eggshell and shell membrane to infect the contents of the egg;Eggs with heavy surface pollution will reproduce in large quantities in a short period of time and invade the inside of the egg.
Salmonella that needs to be alert
Salmonella is a major foodborne pathogenic bacteria commonly found in eggs, meat and raw milk.
Salmonella may contaminate the eggs by infected hen reproductive tissue before the eggshell forms, and in turn contaminate the inside of the egg.
What's even more terrifying is that salmonella is particularly easy to feed:Resistant to salt and low temperatures, can survive in a dry environment for several weeks, in water for 3 weeks, and in feces for 2 months. After being infected with salmonella, it can cause abdominal pain, diarrhea, nausea, vomiting, and fever, and may lead to death in severe cases.
Suggestions on eating eggs safely
Although the salmonella in eggs is dangerous, it is not difficult to deal with. When eating eggs, you can avoid its damage to the greatest extent.
01
Eggs should be cooked
Fresh food completely, it is a very effective method of sterilization. When eating fully cooked eggs, you don’t have to worry about salmonella.
02
Buy and save eggs correctly
Purchase eggs in supermarkets and choose clean and complete egg shells. Eggs with more contaminants on the egg shell and eggs with cracks are more likely to be contaminated by pathogenic bacteria, so it is best not to buy them.
After buying it, you can store it in a cool and dry place, it is best to refrigerate in the refrigerator, and store it separately from fruits and vegetables, meat, etc. to avoid cross-contamination.
Usually, the eggs you bought do not need to be cleaned,But if there is a lot of chicken manure and soil on the surface of the egg shell, you can clean it. The washed eggs should be eaten first in a short period of time.
And it is necessary to note that eggs that have been refrigerated should continue to be kept at refrigerated temperature and do not transfer the previously refrigerated eggs to room temperature for storage. Because of the temperature difference, water droplets will form on the egg shell, which may help microorganisms enter the egg and make the eggs spoil easily.
03
Don't save it too long
Don't buy too many eggs at a time. It is better to buy less and buy frequently to avoid storage time for too long. Although there is a protective film on the surface of the egg, as the eggs are stored for longer and longer, the protective film will become weaker and weaker in protecting the eggs. Moreover, the longer the eggs are stored, the more likely they are to be contaminated by salmonella inside.
04
Try not to eat soft-boiled eggs
Soft-boiled eggs are often the egg white has solidified and has a soft texture, while the egg yolk is still in a liquid and flowable state. The center temperature of the egg yolk in this state may not reach above 60℃, which will be difficult to kill salmonella, which may carry salmonella and other bacteria, increasing the risk of food poisoning. In contrast, the consumption of whole-cooked eggs is relatively safe.
If you really like to eat soft-boiled eggs, choose the "raw eggs" produced by a regular manufacturer and store and eat them according to the instructions.
Source: AI Generation
05
Don't rinse eggs in boiling water
Eggs taken out of the refrigerator may not reach the temperature to kill salmonella, and they are basically drunk after rinsing, so the time cannot meet the sterilization requirements. Such operations cannot guarantee that all salmonella and other bacteria will be killed, and will increase the risk of food poisoning.
06
Eating feather eggs is not recommended
Feed eggs are "gathered" during the hatching process, that is, stillfetal eggs. may contain parasites and pathogenic bacteria such as salmonella, E. coli, and typhoid bacteria, which will increase the risk of food poisoning.
In short, although eggs are delicious, you must pay attention to the safety of consumption. Although we cannot see the "dirtiest" pathogenic bacteria on eggs, we are dangerous and must not be taken lightly.
References
[1]https://www.cfs.gov.hk/sc_chi/multimedia/multimedia_pub/multimedia_pub_fsf_29_01.html
[2]Zhao Lei, Luo Hongxia, Huang Yanfang, Wang Jian, Ju Ronghui. Detection and analysis of three main pathogenic microorganisms of commercially available eggs [J]. Modern Food Technology, 2010, 26(2):200-202
[3]Wang Jie. Investigation, analysis of egg salmonella contamination and research on fresh-keeping technology in Baoding area [D]. Hebei University of Engineering, 2021.DOI: 10.27104/d.cnki.ghbjy.2021.000449.
Source: Popular Science China, reproduced from People's Daily Popular Science WeChat Official Account
