Raw milk that has been heated for a set period and temperature to kill any microorganisms it may have is known as pasteurised milk.

Microorganisms like bacteria that cause disease are known as pathogens. Pathogens like Campylobacter, E. coli O157:H7, Salmonella, Listeria, and other bacteria can be found in raw milk. Raw milk is the milk of dairy animals such as cows, goats, sheep, and others.

5. When exposed to sunlight, milk is susceptible to oxidation.

• Packaging
The proper packaging of milk is crucial not only to maintain its nutritional value and save waste but also to increase its marketability and generate higher profits. The packaging industry's challenge is to provide consumers with nutrient-dense milk in the most cost-effective, hygienic, secure, and ecologically responsible package possible. For fluid milk, there are primarily two types of packaging solutions.

One is the conventional bottling method, where the container must be returned to the dairy, and the other is the one-way distribution method, where the container is disposable and does not return to the dairy. There are several alternative systems used in the non-returnable distribution system where various packaging materials, shapes, sizes, forms, and machines are used for packing.

Knowing the key traits of milk and milk products is crucial for choosing an appropriate packaging material.

• Criteria for Selection of Milk Packaging Material for Pasteurised Milk
Milk requires precise packing materials to maintain its original quality for some time because it is such a perishable and delicate product. The following features of pasteurised milk packaging are essential:

1. There should be no off-flavours in it.
2. It shouldn't give the product any taste or flavour.
3. It ought to serve as a barrier against bacterial infection.
4. It should be UV light resistant (max transmission: 8 Percent at 500 nm & 2 Percent at 400nm).
5. It shouldn't affect the products physiologically.
6. It must have strong mechanical qualities (sealing, tensile, structural strength, etc).
7. It must be impervious to tamper.
8. It should have good capabilities for blocking oxygen.
9. It should be cost-effective.
10. It ought to be able to be processed in line.

• Materials Used

1. Glass
2. Plastics: (1) LDPE is commonly utilized; (2) LLDPE: the film is used that is 25% thinner, and (3) LDPE and LLDPE are used in a 5:1 to 4:1 ratio.
3. Additional materials: wax-coated paper board and coated paper board (Extended Shelf life Pouch).

• Classification of milk packaging materials can be done broadly in two categories which can be seen from the below flow diagram.

No.	Materials	% Consumption		Examples of Use
India	Global
1	Paper and paper board	40	29	Bags, boxes, cartons
2	Glass	16	8	Bottles, jars
3	Metal	5	19	Cans, aluminum foil
4	Plastics	15	39	Overwraps, bags, cups, bottles
5	Wood	--	--	Crates, pallets
6	Cloth	--	--	Sacks
7	Laminates	--	--	Multilayered plastics, cartons
8	Others	24	5	---

• Importance of packaging
A package's duties include preserving food's quality and freshness, enhancing its appeal to draw customers, and making storage and transportation easier. A package's essential features can be divided into five main groups.

To Contain the Product
Any package's main job is to keep food contained while facilitating handling, storage, and distribution from the producer to the final consumer or even during the time the remainder is consumed by the consumer. There are typically different levels of packing, though. Primary packaging is one that directly contacts the object it is intended to hold, such as a metal can, a glass jar, or a plastic bag. A primary packaging must, by law, not contain any material that could endanger the consumer's health. Bundling many primary packages together furthered handling convenience and gave rise to the idea of secondary packages.

Corrugated boxes, such as those used to pack apple juice tins, are examples of secondary packaging. These secondary containers are frequently palletized and secured with metal strapping or, more frequently, by shrink- or stretch-wrapped film to create even another degree of packing, i.e. tertiary packaging, as handling and shipping techniques have advanced.

Then, for long-distance shipment by air, land, or sea, these pallet loads may be quaternary packaged into substantial metal containers. Packing also refers to secondary, tertiary, and quaternary packaging. In this regard, the following are taken into account.

1. Proper size and form (biscuit package, tubs for detergent)
2. Proper constructional features.
3. No diffusion, spills, or leaks—loss prevention.
4. The package must include the product in its natural state (biscuits packed in a Pillow pack, to prevent damage)
5. No additional damage during handling, transportation, or storage following packaging.
6. As a result, the package needs to be sturdy enough to hold the product as is.
7. Best compatibility with the product (nontoxic, not soluble in product... Inert to the product; no physical, chemical, or biological changes or modifications.)
8. Containment or agglomeration - For the sake of efficiency, small objects are frequently bundled together in a single packaging. For instance, handling 1000 single pencils is more physically demanding than managing 1000 boxes of pencils. We require containment for liquids, powders, and granules.

To Protect the Product
Any container's ability to safeguard the goods inside from potential loss, damage, deterioration, spoiling, or contamination throughout the supply chain is one of its most crucial features. Packaging can guard against physical harm, such as bruises brought on by vibrational shocks during shipping or storage. Proper packaging will also stop material loss, such as potatoes falling out of a flimsy bag or juice spilling out of a can.

Additionally, packaging can shield products from moisture gain or loss, dust, and light, particularly UV radiation, which degrades some light-sensitive products. Additionally, it can shield the food inside the package from temperature changes while it is being transported frozen or chilled.

Additionally, packaging can be utilized to regulate the oxygen availability of fruits and vegetables, safeguard against flavor or smell loss, and support the preservation of products' nutritional value. The product may also be shielded from microbial spoilage by bacteria, yeasts, and molds with proper packing. Additionally, it can guard against rodent and insect-caused microbial decomposition of stored goods.

Medium of communication
Any food package should serve several purposes, including identifying the product and its origin, instructing the consumer on how to utilize the food, offering any further information that may be required, and, most importantly, luring the user's attention and promoting product purchase. For many years, package design has been a significant and dynamic phenomenon. Graphic design and marketing communications are used to decorate the packages outside and, frequently, the point of sale or display. The following are some examples of the information a package may provide to the customer:

1. Product production and recommended purchase dates
2. Adequate storage circumstances
3. Recipe directions
4. Dimensions and quantity of portions or servings per pack
5. Amount of calories per serving
6. Name and location of the manufacturer
7. Price
8. Recipe recommendations
9. Nation of origin
10. Information transfer - Labels and packaging explain how to use, transport, recycle, or discard the product or package.

Means of minimising costs
The fact that packaging lowers prices for the consumer is a significant aspect that is frequently ignored. By lowering the cost of processing, packaging lowers the price of food. Foods can be prepared close to where they are harvested, waste can be handled on-site, and shipment weights can be cut to decrease transportation costs. The economics of bulk storage, warehousing, transport, and distribution depends on how well packages are handled in large quantities.

A product's proper packaging enables efficient and automated handling, distribution, and marketing, which lowers the significant labor expenses that would otherwise need to be factored into the product's price. Packaging serves to transport things in a way that is most advantageous from the place of production to the point of use; therefore it does more than just contain the commodity.

All facets of handling, storing, preserving, distribution, advertising, sales promotion, display propensity, preparation, and several other industrial facts are included in this.

Means of selling product
Marketers can use the product's packaging and labeling to persuade potential customers to buy it. Packaging is frequently called the "silent salesman." When Robertson (1992) said that a package "must protect what it sells and sell what it protects," he succinctly encapsulated the multifunctional nature of packaging.

Features for distribution, handling, presentation, sale, opening, reclosing, use, and reuse can be added to packages. To facilitate the selling of goods, primary packages should, in Jelen's opinion (1985), have the following features:

1. Sanitary
2. Not harmful
3. Transparent
4. Lightweight
5. Tamper obvious
6. Simple to handle and pick up
7. Easily inserted into refrigerators, shelves, cabinets
8. Simple to open and use
9. Simple to close
10. Returnable, recyclable, or reusable
11. Secure and free from risks like shattered glass or razor metal edges
12. Present the item
13. Glamorize: Use embellishment, embossing techniques, and exotic closures to give the appearance of something highly valuable, but avoid misleading the public.

Preserve
Protect and keep the remaining product in its container for a prolonged or desired amount of time.

Measurement and portion control
A single serving or single dosage container has a specific amount of contents to regulate usage. Bulk goods (like salt) can be broken up into packages that are more suited for each home. Selling sealed one-litre milk bottles rather than requiring customers to bring their bottles to fill themselves helps with inventory control.

Security
Packaging can be very helpful in lowering transport-related security hazards. Improved tamper resistance and tamper-evident features can be added to packages to help detect tampering and discourage it. The architecture of some packages makes them more resistant to pilferage, while some feature pilferage-indicating seals. Packages can be designed to help lower the hazards of package pilferage.

To help show that the package and its contents are real, packages may come with authenticity seals. Additionally, packages may have anti-theft components like dye packs, RFID tags, or electronic item surveillance tags. These components can be turned on or detected by equipment at exit points and need specialist skills to be turned off. This kind of loss prevention involves the use of packing.

• Types of packaging materials used for milk packaging
Flexible pouches, which predominate in terms of total milk packaging, are followed by aseptic packaging, whose use is steadily rising. Flexible pouches have established themselves as a rapid, inexpensive, and secure packing option. They are also simple to package and handle because of their extensive distribution network.

The adoption of new technologies was made possible by the positive consumer reaction to milk pouches. The plastic film is formed into a tube, sealed along its length, sealed at the bottom to form a pouch, filled with milk, and then sealed at the top in the form-fill-seal (FFS) method. Due to its superior cold storage qualities, butane LLDPE, also known as C-4, and octane LLDPE, also known as C-8, are commonly used.

1. Glass bottles
The earliest method of packaging milk is in glass bottles. The bottles used are 500 ml clear glass bottles that adhere to IS: 1392 - 1967. The advantages of glass bottles are their compatibility, rigidity, hygienic and non-toxic nature, and transparency. In this technique, dairy bottles are cleaned and sterilised as well as collected and transported to a processing facility.

This packing strategy necessitates a sizable storage area for both filled and empty bottles. These elements raise both fixed and variable expenses. Due to bottle inconveniences caused by their heavy weight, fragility, and returnability, both distributors and consumers found this packaging solution to be unsatisfactory and it is no longer in use.

2. Returnable plastic bottles
Although there is less risk of breaking and plastic bottles are lighter, most other aspects of milk packing in glass bottles remain the same.

3. Non-returnable plastic bottles
In comparison to other systems, this system lowers transportation costs due to the lightweight and convenient bottle delivery method.
Example: a car buoy or HDPE with a PP lid.

3.1 Plastic films
In most cases, low-density polyethylene (LDPE) film is used to make plastic pouches. The benefit of co-extruded LDPE-LLDPE film in reducing pin-hole issues makes it another popular choice. The films are 45 to 75 microns thick. On form-fill-seal (FFS) machines, the pouches are created and filled with a capacity of 200, 500, or 1000 ml.



The movie ought to comply with IS: 11805 - 1999. Since the plastic pouches are not reused, there is no need for cleaning, which prevents energy loss. They are clean, hygienic and suitable for this purpose. These pouches can also be easily recycled for different uses.

3.1.1 Developments in milk packaging in plastic pouches
Due to its convenience and lower cost, the milk pouch idea originally started in Europe in the late 1950s and quickly gained favour among customers. For milk packaging, polyethylene, in particular, LDPE has been utilised. Milk was packaged in 0.09 mm thick white pigmented film in Czechoslovakia.

Milk is typically packed in co-extruded PE laminate in Denmark and Finland, which has an inner layer of black and an outside layer of white. Certain Dairies utilized the same packaging in India. In North America, transparent plastic is widely utilized. The LDPE film's thickness was gradually lowered to 55 to 65 microns. Milk pouches are being made in India from 50–55 thick LLDPE films.

3.2    Aseptic packaging of milk
In Sweden, aseptic or long-life milk was first made available in the early 1960s under the "Tetra-pack" name. It makes use of a filling environment warmer and a laminate pre-steriliser. The flexible laminate includes aluminium foil as a necessary component to act as a barrier against light and gas. UHT processing involves preheating milk to 73–850°C, quickly raising it to 135°C for a brief period, and then abruptly cooling it by flashing it into a vacuum chamber.

It must be packaged in sterile conditions only. For at least three to six months, refrigeration is not required. A self-life of up to a year is feasible if kept under refrigeration.

In addition to protecting milk from bacteria, packaging must also shield it from ambient oxygen, moisture, and light as well as from the environment's unfavourable scents (in the case of milk powders).