Milk packaging features

Sterilization Methods

When you pick up a milk carton, you'll notice different sterilization methods marked on the top. These can generally be categorized into three types: pasteurized milk, sterilized milk, and ultra-high temperature (UHT) sterilized milk.

Pasteurized Milk: Typically comes in simple plastic bags, bottles, or glass containers. Plastic bags are commonly made from polyethylene.

Lee: Pasteurization usually occurs at temperatures below 100°C. It's often done at 72-75°C for 15-16 seconds or 80-85°C for 10-15 seconds. This low-temperature process helps preserve the fresh taste of raw milk, with minimal loss of nutrients, especially B vitamins—only about 10% are lost.

Cons: Since it doesn't fully eliminate all bacteria, some heat-resistant microorganisms may remain. If conditions are right, they can multiply. Therefore, this type of milk typically requires cold chain storage and transportation, making it less convenient for carrying around.

Sterilized Milk: Usually packaged in composite plastic bags, paper-plastic composites, aluminum foil packages, or pillow-shaped and brick-style containers. These materials offer better barrier properties against light and air.

Lee: Sterilized milk undergoes high-temperature treatment above 100°C, which kills all active bacteria and spores. After aseptic filling, it can be stored at room temperature, making it easy to carry and transport over long distances.

Disadvantages: The high heat can cause some flavor components to degrade, resulting in a less fresh taste compared to raw milk. B vitamin loss ranges between 20% to 30%. Some people find it watery or less flavorful, so it's important to choose based on personal preference.

UHT Sterilized Milk: Often comes in composite plastic bottles or aluminum foil boxes. These also provide good protection against contamination.

Lee: Similar to sterilized milk, but sometimes undergoes secondary sterilization, leading to even greater nutrient loss.

Shelf Life Variations

Different sterilization methods result in varying shelf lives. Generally, they fall into three categories: short-term, monthly, and semi-annual.

Short-Term: Shelf life of about 7 days, typically 3-5 days. This type uses low-temperature pasteurization. It’s ideal for people who consume milk at home or live close to a supermarket, where they can buy fresh milk daily. For best quality, try to purchase before 5 p.m., as milk sold after that time might not be as fresh.

Monthly: Shelf life of around 30 to 45 days. High-temperature sterilization ensures longer preservation without refrigeration. Perfect for office workers who can’t go to the store every day and prefer to have milk delivered to their workplace.

Semi-Annual: Shelf life of up to six months. This is usually UHT milk, suitable for remote areas where delivery times are longer. It’s a great option for those who need milk that lasts a long time without refrigeration.

With so many options available, choosing the right milk depends on your lifestyle, preferences, and storage needs. Understanding the differences between pasteurized, sterilized, and UHT milk can help you make an informed decision.