Why is milk not packaged in aluminum cans?

In the market, milk is typically packaged in paper cartons (such as Tetra Pak), plastic bottles, and glass bottles, while aluminum cans are used less frequently. This phenomenon is not accidental but determined by a variety of factors, including chemical stability, storage conditions, production costs, supply chain adaptability, and market acceptance.

Chemical Stability Issues 

The acidity and proteins in milk may affect the stability of aluminum cans

The pH of milk is about 6.5-6.8, which is weakly acidic. Components such as lactic acid may react with aluminum, causing the release of aluminum ions:

• Acidic effect: Aluminum may dissolve slowly in an acidic environment, leading to the entry of aluminum ions into the milk. This not only affects the taste but also poses health risks, such as neurotoxicity (long-term excessive intake of aluminum is associated with diseases like Alzheimer's).

• Protein adsorption: Proteins in milk may interact with the metal surface, causing precipitation or adhesion, which can affect the flavor and stability of the milk.

• Aluminum cans require a special inner coating, but there are safety concerns

Acidic action: Aluminum may dissolve slowly in an acidic environment, leading to aluminum ions entering the milk, which not only may affect the taste but also bring health risks, such as neurotoxicity issues (long-term excessive intake of aluminum is associated with diseases like Alzheimer's).

Acidic action: Aluminum may dissolve slowly in an acidic environment, leading to aluminum ions entering the milk, which not only may affect the taste but also bring health risks, such as neurotoxicity issues (long-term excessive intake of aluminum is associated with diseases like Alzheimer's).

Protein adsorption: Proteins in milk may interact with metal surfaces, causing precipitation or adhesion, which can affect the flavor and stability of the milk.

Protein adsorption: Proteins in milk may interact with metal surfaces, causing precipitation or adhesion, which can affect the flavor and stability of the milk.

Aluminum cans require special inner coatings, but there are safety concerns

Aluminum cans require special inner coatings, but there are safety concerns

To prevent direct contact between aluminum and milk, aluminum cans usually use an inner coating (such as epoxy resin) for protection. However, this brings new problems:

To prevent direct contact between aluminum and milk, aluminum cans usually use an inner coating (such as epoxy resin) for protection. However, this brings new problems:

• Increased production costs: Compared to paper boxes and plastic bottles, the coating process for aluminum cans increases production costs.

• Food safety concerns: Some epoxy resins contain bisphenol A (BPA), a chemical that may affect the endocrine system, and long-term intake may pose potential health risks to the human body.

Increased production costs: Compared to paper boxes and plastic bottles, the coating process for aluminum cans increases production costs.

Increased production costs: Compared to paper boxes and plastic bottles, the coating process for aluminum cans increases production costs.

Food safety concerns: Some epoxy resins contain bisphenol A (BPA), a chemical that may affect the endocrine system, and long-term intake may pose potential health risks to the human body.

Food safety concerns: Some epoxy resins contain bisphenol A (BPA), a chemical that may affect the endocrine system, and long-term intake may pose potential health risks to the human body.

Aluminum cans are not suitable for the storage conditions of milk

Aluminum cans are not suitable for refrigerated storage

Strong thermal conductivity: The thermal conductivity of aluminum is much higher than that of plastic and paper boxes. Under refrigeration conditions, water droplets easily condense on the surface of aluminum cans, affecting storage and transportation.

Easily deformed, affecting seal integrity: Aluminum cans may deform due to gas expansion or contraction in environments with large temperature fluctuations, which can affect the sealing effect and increase the risk of contamination.

Aluminum cans are not conducive to aseptic treatment of milk

Milk typically has two main sterilization methods:

Pasteurized Milk (Pasteurized Milk): Requires full cold chain transportation, while aluminum cans are inconvenient for storage and transportation. Paper boxes and plastic bottles are more suitable for refrigeration.

Ultra-High Temperature Milk (UHT Milk) (Ultra-High Temperature Milk): Uses high-temperature sterilization at around 135℃. The sealing method of aluminum cans is not as good as that of aseptic paper boxes, making them more susceptible to secondary contamination after sterilization.

In addition, aseptic packaging technologies such as Tetra Pak are mature and can be stored at room temperature for long periods. In comparison, aluminum cans do not have a significant advantage.

Production and Cost Factors

Aluminum can packaging is more expensive

Milk is a bulk consumer good, mainly operated on a low-cost, high-circulation model globally, while the manufacturing and packaging costs of aluminum cans are significantly higher:

• High production costs: The manufacturing and sealing processes for aluminum cans are complex, especially the stringent requirements for liquid sealing technology. In contrast, the processes for paper boxes and plastic bottles are more mature and relatively less expensive.

• Increased transportation and storage costs: Aluminum cans take up more space compared to foldable paper boxes, leading to increased transportation costs during warehousing and logistics processes.

High production costs: The manufacturing and sealing processes for aluminum cans are complex, especially the stringent requirements for liquid sealing technology. In contrast, the processes for paper boxes and plastic bottles are more mature and relatively less expensive.

Increased transportation and storage costs: Aluminum cans take up more space compared to foldable paper boxes, leading to increased transportation costs during warehousing and logistics processes.

The aluminum can supply chain does not match the dairy industry

The dairy industry's supply chain is characterized by fast production and quick circulation to minimize losses within the shelf life. However, the production and filling processes for aluminum cans are relatively complex, resulting in poor supply chain adaptability:

• The automation of production and filling for paper boxes and plastic bottles is more efficient, while the filling and sealing process for aluminum cans requires higher standards, making the overall packaging speed slower.

• Given the relatively short shelf life of milk, using high-cost, low-efficiency aluminum can packaging is economically unsustainable.

• In comparison, aluminum cans are typically used for carbonated drinks, beer, and functional beverages, which have higher prices that can cover the higher packaging costs. However, the market positioning of milk favors lower-cost packaging solutions.

The automated production and filling efficiency of paper boxes and plastic bottles is higher, while the filling and sealing process for aluminum cans requires more, resulting in a slower overall packaging speed.

Given that milk has a relatively short shelf life, using high-cost, low-efficiency aluminum can packaging is economically unsustainable.

In comparison, aluminum cans are typically used for products such as carbonated drinks, beer, and functional beverages, which have higher prices and can cover the higher packaging costs. However, the market positioning of milk determines its preference for lower-cost packaging solutions.

Consumer Acceptance and Market Preferences

Different Consumer Habits

Currently, milk packaging on the market is mainly dominated by paper cartons, plastic bottles, and glass bottles, which have long formed a fixed perception among consumers. Aluminum cans for milk have lower recognition, making market promotion difficult.

Aluminum Cans Do Not Fit the Brand Image of Milk

Aluminum cans are primarily used for carbonated drinks, and consumers often associate them with soda, beer, and energy drinks, while milk emphasizes "health, naturalness, and freshness," which does not match the fizzy association with aluminum cans.

Visual and Tactile Differences: Aluminum cans typically give an impression of being cool and stimulating, whereas milk emphasizes warmth and nutrition. From a sensory experience perspective, aluminum cans are not well-suited for shaping the brand image of milk.

Exception: Milk Products in Aluminum Cans

Although regular milk is rarely packaged in aluminum cans, certain types of specialty dairy products still use this packaging:

• Premium coffee milk, flavored milk, and milkshakes: Some brands opt for aluminum cans to enhance the product's perceived quality and take advantage of the high light barrier properties of aluminum to extend shelf life.

• High-fat dairy products such as vegetable fat cream and condensed milk: These products differ fundamentally from regular milk, often being thicker and more stable. Some brands choose to package them in aluminum or metal cans.

High-end coffee milk, flavored milk, and milkshakes: Some brands use aluminum cans primarily to enhance the product's texture and extend its shelf life by leveraging the high light-blocking properties of aluminum cans.

Vegetable fat cream, condensed milk, and other high-fat dairy products: These products differ fundamentally from regular milk, typically being thicker and more stable. Some brands choose aluminum or metal cans for packaging.