What kind of preserved eggs contain less lead, and what is the approximate lead content of preserved

The "national standard" GB T9694-2014 issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China and the Standardization Administration of the People's Republic of China stipulates that the lead content of preserved eggs shall not be greater than milligrams and kilograms. The implementation of the new national standard announced the end of the lead process of preserved eggs, and in the future, preserved eggs will need to be produced by lead-free process, which will improve the safety of preserved eggs to a new level.

Lead and its compounds are harmful to humans. Frequent consumption of foods containing excessive lead leads to the accumulation of lead in the human body, which is harmful to the human nervous system, immune system, kidneys, etc.

The lead oxide used in our traditional preserved eggs is lead oxide to provide metal ions, so lead ions also penetrate into the preserved eggs in the process of lead ions and the decomposition of the long-lived sulfur ions from the protein in the egg to form insoluble salt sulfide to block the eggshell pores.

In the production process of preserved eggs, it mainly involves the selection of raw eggs, soaking with material liquid, taking out and inspecting, coating mud film, packing and storage, among which sodium hydroxide (NaOH) and metal ions must be used in the process of soaking in raw eggs. NaOH is added to the soaking solution to make the liquid alkaline and promote the coagulation and alkalinization of egg whites and yolks; The main purpose of adding metal compounds is to combine them with the sulfur ions produced by the decomposition of proteins in the egg, generate insoluble salt sulfides and block the pores of the eggshell, hinder the continuous penetration of OH- into the egg, and cause "alkali injury" in the later preserved eggs, resulting in the reprogramming of the coagulated protein in the liquid state.

Many studies have confirmed that lead has a huge toxic effect on the human body, mainly damaging the nervous system, affecting children's memory, language and motor skills and learning ability. As a result, more and more lead-free processes are being used to make preserved eggs. The lead-free process means that no lead compounds are used to provide metal ions during the processing of preserved eggs, but zinc, iron, copper ions, or a combination of these ions are used to provide metal ions.

However, it should be noted that lead-free preserved eggs do not mean that preserved eggs are completely lead-free, because in the natural world we live in, air, soil, and water will contain trace amounts of lead, which will exist in the indispensable raw materials for us to make preserved eggs - fresh eggs, so it is almost impossible to make preserved eggs absolutely lead-free.

To identify the lead content of preserved eggs, it depends on whether the lead content marked on the package is within the range of national standards. According to national regulations, the lead content of every 1000 grams of Songhua eggs shall not exceed 3 mg, and Songhua eggs that meet this standard are also called lead-free Songhua eggs. When buying preserved eggs, try to buy pre-packaged foods produced by regular manufacturers with complete food labels.

Three ways to identify Songhua eggs:

1. Appearance identification. Observe whether its appearance is complete, whether there is damage, mildew, etc. You can also use your hand to feel its elasticity, or hold the egg and shake it to listen to its sound.

The muddy wrapping material of the good-quality preserved eggs is intact and mildew-free, and the eggshell is intact and undamaged after the wrapper is peeled off; elastic after peeling; There is no turbulent sound when shaking.

2. Illumination identification. After removing the wrapping material of the preserved eggs, they were identified according to the light transillumination method of the fresh eggs, and the color, solidification state, and size of the air chamber in the eggs were observed. The contents of inferior preserved eggs are not coagulated, they are watery, and the air chamber is very large.

3. Taste the taste. The whole egg is solidified, non-sticky, clean and elastic, translucent brownish-yellow, with pine pattern-like texture; The egg is cut longitudinally, and the yolk is light brown or light yellow, and the center is thin. Poor quality preserved eggs have a pungent foul odor or a musty smell.