According to the relevant requirements and methods specified in the Guidelines for Stability Study of Powdered Milk Formulae for Infants and Young Children (on Trial), nutrient decay in infant formula milk powder was investigated in accelerated and long-term tests. The results showed that the macronutrients and fatty acids in infant formula milk powder were relatively stable in both tests, with a decay rate of less than 5%. Vitamins did not significantly decay with a decay rate of less than 10%. The mineral iodine decayed evidently in the accelerated test, with a maximum decay rate of 11.37%. Other minerals did not significantly lose. The optional components were relatively stable in the accelerated and long-term tests, with a decay rate of less than 5%.

The production and storage process are closely related to the quality of infant formula milk powder. This study examined nutrient mixing homogeneity, the decay rate of nutrients and the changes in safety indicators during accelerated storage of infant formula milk powder. The results showed that among the 15 nutrients selected, the mixing uniformity of lactoferrin was above 90%, while the mixing uniformity of the other nutrients was above 95%. Under the accelerated storage conditions, macronutrients and fatty acids were relatively stable, and vitamins and minerals did not show significant attenuation. The decay rate of taurine as an optional ingredient was relatively high, being 8.06%, 8.40%, and 8.08% at the end of the accelerated storage for milk formulae for younger and older infants and young children, respectively. After accelerated storage for 186 days, the safety indicators (Tin, nitrate, nitrite, aflatoxin M1, and melamine) remained basically unchanged.

The wet process for producing infant formula milk powder requires multiple heating processes, which can cause some nutrient loss. Mixing uniformity is an important indicator for measuring the effectiveness of the mixing process, which is used to measure whether various nutrient indicators are evenly dispersed in infant formula milk powder. When designing infant formula milk powder, the loss rate and mixing uniformity of nutrients should be taken into account to ensure that the quality of products meets the requirements of the national food safety standards. This study analyzed nutrient loss rate and mixing uniformity in the wet processing of infant formula milk powder. The results showed that the nutrient that was most lost in the wet process was vitamins. Vitamin A (VA), vitamin B1 (VB1), vitamin B12 (VB12), and vitamin C (VC) were lost by 19.2%, 20.4%, 33.9%, and 20.3%, respectively, while the other vitamins were not significantly lost. Minerals were relatively stable in the wet process, and no significant loss of inositol, taurine or galactooligosaccharides was observed; the mixing uniformity of VB1 was less than 95%, while the mixing uniformity of the other nutrients was above 95%.

Our aim was to understand the pollution levels and sources of chlorate and perchlorate in infant formula milk powder and to evaluate the risk of dietary exposure to chlorate and perchlorate in infants and young children. A total of 165 batches of samples were collected from the water, cow milk, and ingredients used, as well as 131 batches of infant formula milk powder. Chlorate and perchlorate in each sample were detected using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the data obtained were statistically analyzed. The results showed that chlorate and perchlorate were undetectable in the water samples. Cow milk was more severely polluted by perchlorate than by chlorate. Some ingredients were also found to contain chlorate and perchlorate. Infant formula milk powder was contaminated with chlorate and perchlorate, with average contents of 34.3 and 14.5 μg/kg, respectively. The average dietary exposure levels to chlorate and perchlorate for infants aged 0–6 months were 0.71 and 0.28 μg/(kg·d), respectively, which were at an acceptable level. Infant formula milk powder and the raw materials used were found to be contaminated by chlorate and perchlorate.

The composition and content of amino acids in infant formula sold in China were investigated in comparison with human milk at different lactation stages. An amino acid analyzer was used to detect the contents of free and hydrolyzed amino acids in commercial infant formula, and total amino acid content and the proportion of individual amino acids were calculated. The results showed that free amino acids were detected in some of the 12 samples, while hydrolyzed amino acids were detected in all these samples. The average concentration of most amino acids was close to that of human milk at 1 to 60 d of lactation, and higher than that of human milk at 61 to 180 d. The average ratio of essential to total amino acids was 46.43%, which was close to that of human milk. The proportions of methionine and tryptophan to total amino acids were higher than those of human milk, the proportions of arginine and cystine to total amino acids were lower than those of human milk, and the proportion of other amino acids to total amino acids was close to that of human milk. This study reveals the difference in amino acid content between commercial infant formula and human milk.

The composition and content of amino acids in infant formula sold in China were investigated in comparison with human milk at different lactation stages. An amino acid analyzer was used to detect the contents of free and hydrolyzed amino acids in commercial infant formula, and total amino acid content and the proportion of individual amino acids were calculated. The results showed that free amino acids were detected in some of the 12 samples, while hydrolyzed amino acids were detected in all these samples. The average concentration of most amino acids was close to that of human milk at 1 to 60 d of lactation, and higher than that of human milk at 61 to 180 d. The average ratio of essential to total amino acids was 46.43%, which was close to that of human milk. The proportions of methionine and tryptophan to total amino acids were higher than those of human milk, the proportions of arginine and cystine to total amino acids were lower than those of human milk, and the proportion of other amino acids to total amino acids was close to that of human milk. This study reveals the difference in amino acid content between commercial infant formula and human milk.