Grass or Grain? Scientists Reveal Why Imported and Chinese Milk Are Surprisingly Different

Walk down the dairy aisle of any Chinese supermarket and you will find ultra-high-temperature (UHT) milk from China, Western Europe, Australia, and New Zealand sitting side by side, often with imported cartons commanding a premium price. Consumers generally assume that price reflects quality, but a new study published in Food Science of Animal Resources suggests the real story is far more interesting: domestic and imported milks are simply different products, each with its own nutritional fingerprint shaped by what the cows eat, how the milk is processed, and how far it travels before reaching the shopper’s hand.

The research team, led by scientists from Mengniu Dairy’s Ambient Product Research and Development Centres, purchased sixteen commercial UHT whole milk products from the Chinese e-commerce platform Jingdong Mall. Six samples were produced in China, five in Western Europe, drawn from the Netherlands, Germany, Austria, Ireland, and Spain, and five from Australia and New Zealand. Imported products explicitly labeled as grass-fed or pasture were preferentially selected to maximize the likelihood that they represented grazing-based production systems, although the authors caution that label claims do not guarantee the annual diet of any herd. All samples contained only raw milk or organic raw milk with no additives, and all were packed in aseptic cartons.

The analytical arsenal deployed on these sixteen cartons was formidable. Gross composition, including fat, protein, lactose, solid-non-fat, and total solids, was measured by mid-infrared spectroscopy. Fatty acids were quantified by gas chromatography with flame ionization detection according to the Chinese national standard GB 5009.168. Fat-soluble vitamins A and E were determined by high-performance liquid chromatography with diode-array detection, while riboflavin was measured by HPLC with UV/visible detection. Niacin, pantothenic acid, and folic acid were assessed with commercial assay kits, choline by ion chromatography, and a panel of minerals, including calcium, potassium, sodium, magnesium, zinc, selenium, and iodine, by inductively coupled plasma mass spectrometry. Phosphorus was determined spectrophotometrically. This breadth matters because single-nutrient comparisons can be misleading; milk quality is a multivariate property.

The macronutrient results revealed a subtle but telling pattern. Measured fat and lactose levels of the domestic samples were significantly higher than those of the imported milks, and the domestic products showed the highest fat, vitamin E, vitamin B3, zinc, and iodine content, while milk from Australia and New Zealand had the lowest levels of fat, solids, and vitamin A. Interestingly, the measured fat and protein values for domestic milk exceeded typical raw-milk averages reported for China, pointing to standardization practices in dairy processing, particularly for domestic products claiming 3.6 grams of protein per 100 milliliters. Minerals tied to casein micelles, such as calcium, phosphorus, and magnesium, showed no significant regional differences, likely because protein standardization counteracts the feed-driven variation that previous studies have documented for grazing versus total mixed ration systems.

The vitamin findings may be the study’s most counterintuitive result. Fresh and ensiled grass is an excellent source of fat-soluble vitamins, so one might expect pasture-fed European and Oceanian milk to contain more vitamin A and vitamin E. The opposite was observed. The researchers attribute this to the harsher thermal reality of imported UHT milk: longer transportation distances demand longer shelf lives and higher heat loads, and quality reports cited in the paper show imported UHT milk carried markedly higher heat-load indicators such as furosine and lactulose between 2021 and 2023. Vitamin A degrades through isomerization of its unsaturated isoprenoid side chain during thermal processing, and vitamin E loss increases with temperature and holding time. Degradation continues even under refrigeration, with losses of roughly 8 percent for vitamin A and 11 percent for vitamin E after thirty days of storage. In contrast, water-soluble vitamin B2 was higher in imported milk, consistent with its origin in green leafy forage, while vitamin B3, derived mainly from cereal grains, was higher in domestic milk, matching expectations for grain-heavy total mixed rations.

The fatty acid analysis produced perhaps the clearest separation between regions. Total saturated and monounsaturated fatty acids did not differ significantly, but the polyunsaturated fatty acid picture split sharply along the n-3 and n-6 families. Domestic Chinese milk was richer in n-6 fatty acids, including C18:2n-6c, C18:3n-6, C20:3n-6, and C20:4n-6, whereas imported milks carried higher levels of n-3 fatty acids such as C18:3n-3, C20:3n-3, and C20:5n-3. The imported samples achieved an n-3/n-6 ratio of approximately 0.31 to 0.32, compared with only 0.12 for Chinese milk. The biochemistry behind this split is well understood: pasture is rich in alpha-linolenic acid, an omega-3 precursor, while maize silage, cereals, and oilseeds in mixed rations supply abundant linoleic acid, an omega-6. These dietary fatty acids are then elongated and desaturated in the mammary gland, amplifying the regional differences in long-chain polyunsaturates.

Shorter-chain fatty acids told the same story from a different angle. Imported milk contained significantly higher levels of C4, C6, C12, and C14, reflecting the fact that high-fiber pasture diets stimulate de novo fatty acid synthesis in the udder, whereas the high-starch rations of confined systems lower ruminal pH and suppress this synthesis. Odd-chain fatty acids, C11, C15, C17, and C21, were also significantly elevated in imported milk, and these compounds are recognized biomarkers of pasture-based feeding because they arise from rumen microbial fermentation of forage. The paper notes that omega-3 fatty acids are associated with reduced risk of cardiovascular disease, diabetes, cancer, and mental disorders, and that the dietary n-3/n-6 ratio of Chinese consumers is suboptimal. However, the authors are careful to add a crucial caveat: milk products account for only about 2.3 percent of Chinese food intake and roughly 1 percent of daily milk fat consumption, so switching to imported milk alone cannot transform the overall dietary fatty acid profile. Pairing milk with omega-3-rich foods such as deep-sea fish, nuts, and flaxseeds remains essential.

Sensory evaluation added a human dimension to the chemistry. Eight trained, certified assessors evaluated the samples in duplicate on a nine-point hedonic scale after a structured three-day training program. Imported milks scored significantly higher for cowy and tea flavors and for astringency, while domestic samples appeared brighter in color and sweeter. The yellow-cream hue of grass-based milk reflects high carotenoid and riboflavin levels in forage, whereas total-mixed-ration milk tends toward white. The cowy note is linked to compounds such as p-cresol, a consistent marker of pasture diets, and the higher sweetness scores for domestic milk align with its higher measured lactose content. Notably, despite the heavier heat treatment of imported products, no significant difference in cooked flavor emerged between groups. The authors candidly acknowledge a limitation: Chinese assessors unfamiliar with imported milk may score attributes differently from their Western counterparts, and previous cross-cultural work has shown Irish and Chinese panelists interpreting the same pasture-milk attributes in opposing ways.

Principal component analysis wove all these threads together into a single picture. Two principal components explained 56.7 and 18.2 percent of the variance respectively, and the first component cleanly separated domestic from imported milk. Domestic samples clustered tightly, characterized by higher vitamin E, fat, and n-6 fatty acids, while the imported samples scattered more widely, positively correlated with vitamin B2, n-3 fatty acids, short- and medium-chain fatty acids, long-chain fatty acids, astringency, and tea flavor. That dispersion, the researchers suggest, reflects the diversity of feeding systems, processing technologies, and storage conditions across Western European and Oceanian countries, in contrast to the large-scale standardized farming and industrial production that dominates the Chinese dairy sector.

The study concludes with practical recommendations that extend beyond shopping advice. Because average dairy intake among Chinese adults was only 27.6 grams per day in 2018, less than a tenth of the 300 grams recommended in the national dietary guidelines, the authors argue that even meeting the current recommendation would not fully satisfy needs for calcium, selenium, and vitamin B2, and they suggest that intake above 500 grams per day of milk and dairy products may be needed. They also call for exogenous vitamin A fortification, better retention of vitamins during storage and transport, and regulation of grass-fed and pasture label claims in the Chinese market, including nutrient indicators such as n-3 fatty acid content. The work was funded by the China government guides local funds for scientific and technological development under grant number 2024ZY0146, and the authors declare no competing interests. For consumers, the takeaway is refreshingly even-handed: neither domestic nor imported milk is simply better. They are products of two different agricultural philosophies, and understanding that difference is the first step toward an informed choice.

Subject of Research: Comparative nutritional composition, fatty acid profiles, and sensory characteristics of commercial UHT bovine milk from China, Western Europe, and Australia/New Zealand sold in the Chinese market

Article Title: Nutritional composition, fatty acid profiles, and sensory characteristics of commercial bovine milk from different global production regions in the Chinese market

Article References: Yang, J., Wang, M., Hu, P., Li, S., Qian, W., & Li, H. (2026). Nutritional composition, fatty acid profiles, and sensory characteristics of commercial bovine milk from different global production regions in the Chinese market. Food Science of Animal Resources, 46(1), Article 80. https://doi.org/10.1007/s44463-026-00086-5

Image Credits: AI Generated

DOI: 10.1007/s44463-026-00086-5

Keywords: UHT milk, dairy nutrition, fatty acids, pasture feeding, total mixed ration, vitamins, sensory analysis, China dairy market, omega-3, food science, milk composition, principal component analysis