Does soft-boiled egg contain bacteria?

Soft-boiled eggs are a kind of food that is deeply loved by people in daily life. They are not only delicious but also have very high nutritional value. However, many people don’t know that soft-boiled eggs may also contain bacteria, which can cause certain harm to people’s health. What we need to understand is that unwashed eggs and half-cooked eggs may carry bacteria, so we need to be extra careful when eating them.

1. Washing eggs is not safe

The physiological structure of poultry is different from that of livestock. It does not have a dedicated birth canal. The fallopian tubes, ureters and intestines converge in a place called the cloaca, which means that feces, urine and eggs are all discharged from the anus. This makes the surface of eggs particularly susceptible to contamination by pathogenic bacteria. Even "clean eggs" from regular laying hen farms that have undergone cleaning and drying may still contain pathogenic bacteria.

In addition, pathogenic bacteria carried in the chicken's intestines can also infect the oviduct through the cloaca, causing contamination inside the eggs. Therefore, even if the outside of the eggs is washed spotlessly, the inside may still be contaminated.

The pathogenic bacteria that may appear in eggs are mainly Salmonella, Escherichia coli and Campylobacter jejuni. For adults, a small amount of bacteria is unlikely to cause serious illness, but for the elderly, infants and young children with low immunity, these bacteria may cause serious consequences.

2. What does the perfect egg taste like?

Friends who like to watch Japanese dramas will find that Japanese people like to eat raw eggs in ways such as raw egg rice and sukiyaki. Since they are fine after eating it, why can't we follow suit? In fact, Japanese farms must vaccinate laying hens against Salmonella, and eggs must undergo several Salmonella tests before leaving the factory to ensure their safety for raw consumption. If you don’t have the habit of eating raw eggs and don’t have the corresponding inspection procedures, it is best not to eat raw eggs.

However, eating raw eggs is indeed the most intuitive way to test the quality of eggs. The flavor of eggs is lightest when they are freshly laid, with the egg white having almost no odor and the egg yolk having a light sweet milky aroma. The longer the storage time, the worse the taste. After a certain period of time, the egg white will even emit a faint sulfur smell, and the egg yolk will have an unpleasant fishy smell. Therefore, the length of time the eggs are stored directly affects the taste of the eggs. Freshness is king for a good egg.

Generally speaking, when the proportion of high-protein feed such as soybean meal or fish meal is large, the taste of eggs will be slightly fishy. The breeding environment and physical and mental condition of laying hens will also have some impact on the flavor of eggs, but these are not as great as the impact of freshness on the flavor of eggs. If eggs are left at room temperature for one day, the degree of deterioration is equivalent to about a week in a refrigerated environment, so fresh eggs should be stored in the refrigerator.

3. Half-cooked may also carry bacteria

Raw eggs can’t be eaten, but what about half-cooked eggs?

Yolk coagulation is a process of protein denaturation, which requires a temperature of about 70 degrees Celsius. A half-cooked egg means that the internal temperature is less than 70 degrees Celsius.

According to the recommendations of the World Health Organization, food must be heated to above 70 degrees Celsius before it can be safely eaten. This is because at 70 degrees Celsius, the protein inside the bacteria will also denature and the bacteria will die. That is, if the yolk has not set, there may be bacteria.