Preserving the nutritional values, safety and authenticity of milk.
Milk is a natural source of fats, minerals, nutrients, micronutrients and vitamins necessary for a balanced diet. It is also essential for the growth and development of infants and toddlers up to early childhood. Toddlers between the ages of one and three are recommended to have an intake of 350 to 400 ml of milk per day to ensure that they receive the right amount of this nutrient.
Breast milk or infant formula is given to babies for at least the first six months of their life, and between the ages of one and two, whole milk and dairy products are recommended to ensure that babies receive essential vitamins that they otherwise could not get from lower-fat alternatives.
The global dairy products market is expected to reach a compound annual growth rate (CAGR) of 5% by 2025, with the milk segment dominating sales3. In 2018, the value of global milk production increased by 2.2% to 843 million tons from the previous year, with production growth in South Asia, Europe and North and South America despite a decrease in milk production in China and Ukraine during this same period.
Given the market growth in the global dairy industry, the future of milk and other dairy products is relatively unpredictable. However, while their trade is ongoing and will increase in the next four years, validating the nutritional values, safety and authenticity characteristics of milk and dairy products is fundamental for both consumers and producers.
Milk and its related products are tested for three main reasons within the food and beverage industry:
By testing these three factors, consumers are more protected against mislabeled, fraudulent and potentially contaminated dairy products that may have reached the market without regulation.
Testing the nutritional values of milk is important so that consumers can make informed decisions about their purchases. Above all, manufacturers of specific products, such as infant formulas, for example, must adhere to inflexible nutritional values determined by regional, national or international regulatory bodies.
To help consumers make these decisions about their milk and/or infant formula purchases, it is critical that manufacturers label their products accurately. In doing so, food analysis laboratories can conduct experiments using HPLC, LC/MS/MS and GC systems to accurately measure the content of milk in terms of sugars, fats, vitamins and amino acids.
Monitoring vitamin levels, as well as beneficial (and some essential) elements such as sodium, potassium, magnesium, calcium, selenium, phosphorus, manganese and zinc, provides valuable nutritional information. It is also important to monitor the presence of potentially toxic elements such as arsenic, cadmium, tin, mercury and lead in animal milk, as contamination could originate in animal feed, fertilizers, soil or processing equipment.
In one study, the Agilent 5800 VDV ICP-OES system used with an SPS 4 automatic processor determined calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus and zinc in milk powder and infant formula samples according to the ISO 151514 method. The results showed that the recoveries for all analyses with certified or reference values were within ± 10% of the expected value, thus confirming their nutritional labeling.
Other experimental examples include the rapid analysis of main and trace elements in milk and dairy products using an Agilent 7900 ICP-MS with Ultra High Matrix Introduction UHMI technology and Integrated Sample Introduction (ISIS 3) technology.
Foods of animal origin, such as cow’s milk, go through additional scrutiny for levels of veterinary drugs. Without a sophisticated approach to analyzing cow’s milk samples, analytical challenges are likely to arise due to the complexity of the matrix and the number of pharmaceutical analogues needed to monitor. In addition, the different legislative requirements of various countries require sample references that meet a wide variety of regulatory conditions.
Agilent provides generic extraction protocols using LC/MS solutions (including an LC/MS veterinary drug application kit) that effectively detect a variety of veterinary drugs, metabolites and transformation products in milk and other animal foods. LC, SFC and GC techniques are also used to determine molecular components and advanced sample preparation ensures the efficiency of all technologies.
Another factor to consider when examining the safety of milk is the responsible use of pesticides within the limits established in animal feeds from which cow’s milk is extracted and in other plant-based ingredients that can be added to other dairy products. To validate this, the LC/MS, GC/MS and Q-TOF workflows offer food analysis laboratories the necessary solutions to accurately measure pesticide levels in milk samples.
In addition, food safety studies are routinely performed to detect, quantify and validate the analysis at the trace level of undesirable by-products such as chlorate and perchlorate in store-bought milk and infant formulas. In one particular study, the Agilent 1290 Infinity II LC and the Ultive triple quadrupole LC/MS (LC/TQ)6 were used. The data from this experiment highlight the accurate quantification to one tenth of the level of the maximum residue level (MRL), which is 10 µg/kg in milk and infant formula as defined by the European Commission.
Globally, milk remains one of the most adulterated food and beverage products on the market7. For example, in 2008, the analysis of milk powder from Minhe Hui County, China, revealed contamination by melamine, an organic compound used to make fertilizers and concrete, of 500 times the maximum limit of melamine found in the test samples at that time.8
More recently, in South Asia, the Punjab Food Authority seized almost 80,000 liters of milk to combat the adulteration of dairy products in the local metropolis. The milk was detected to have urea and added water.
In addition to deceiving consumers and manufacturers, food fraudsters can seriously affect people’s health. Fortunately, innovations in analytical instrumentation and testing methods are exposing these illegal acts to restore consumer confidence by validating the authenticity and safety of products such as milk and infant formulas.
Agilent’s analytical instruments and methods are very valuable in the investigation of food fraud, as mentioned in the previous cases, and continue to support clients working on quality assurance and quality control in the food analysis market.
For example, the Agilent 8890 GC and the Agilent 5977B GC/MS single quadrupole mass spectrometer have been used to detect and quantify β-sitosterol in ghee (milk fat) samples to check for adulteration of vegetable oil.11 The presence of β-sitosterol is associated with low quality and is a potential indicator of adulterated milk. The results found 2.24 ppm of β-sitosterol in the ghee sample in which the study was conducted.
Targeted and non-targeted approaches can be used to identify known compounds in milk and other food authenticity tests. The latter is beneficial if the adulterants in milk are new or have not been previously identified by food testing laboratories. Undirected methods using quadrupole time-of-flight mass spectrometers, for example, create a chemical fingerprint of authentic food, making it difficult for food fraudsters to deceive the global food supply chain.
Given that milk sales projections are estimated to increase in the coming years, and with a wider variety of product options in stores and online, it is important that companies like Agilent continue to work in partnership with their food testing customers to eliminate the threat of milk fraud. preserving its nutritional values, safety and authenticity. Above all, dairy manufacturers must comply with multiple food regulations related to quality and safety that are constantly updated. Agilent is here to help our customers so that consumers of their products have confidence in their purchase choice for feeding themselves and their families.