Dairy Science & Technology · Dairy Processing & Product Technology · also Packaging of Dairy Products, Food Packaging Technology
Packaging materials, forms and machines for milk and dairy products, aseptic packaging, shelf-life testing, labelling and sustainability. The agricultural engineering track (storage-engineering-packaging) covers general packaging engineering.
In the exams: ICAR AICE subject 37 Unit 2 and subject 38 Unit 3; ICAR AIEEA-PG group 17 Unit I (packaging materials, intelligent packaging, nutrition labelling); GATE XL-U Section 3
Packaging decides how long a dairy product keeps, how it reaches the consumer, what the consumer is told about it, and what is left over afterwards. Milk and milk products are sensitive to light, oxygen, moisture, odours and micro-organisms, and many are perishable, so the right package — matched to the product, the process, the distribution chain and the market — is as important to quality as the processing itself. Packaging is also under intense scrutiny for its environmental impact.
This manual covers the functions of packaging; packaging materials; testing; barrier properties and permeability; pouch, bottle and carton filling of milk; aseptic packaging; packaging of butter, cheese, powders, ice cream and fermented milks; modified atmosphere, vacuum and shrink packaging; active and intelligent packaging; migration and food-contact safety; labelling and nutrition labelling; and packaging waste, recycling and extended producer responsibility. Filling and packaging machines are described in dairy-processing-equipment, general food packaging science in the food technology track's food-packaging, and general packaging engineering in the agricultural engineering track's storage-engineering-packaging; this manual concentrates on dairy products.
ICAR AICE-JRF/SRF Dairy Technology (subject 37, Unit 2) covers advances in dairy food packaging: packaging materials and their selection and testing, adhesives, graphics, coding and labelling, protective packaging against oxygen, light and moisture, active packaging, packaging of dairy products, MAP and controlled atmosphere packaging, shrink and stretch packaging, retort pouches, microwavable, biodegradable and edible packages, distribution packaging, and safety and migration. Dairy Engineering (subject 38, Unit 3) includes permeability of packaging materials. ICAR AIEEA-PG Dairy Technology names packaging materials, intelligent packaging and nutritional labelling. Regulatory limits and rules differ by country and change frequently; the examples here must be checked against current law.
Packaging is an integral part of a dairy product, not an afterthought. Its functions are usually grouped into four. Containment holds the product so that it can be handled, filled, transported and sold, from a 200 mL pouch to a 25 kg powder bag or a tanker. Protection keeps the product safe and of good quality until it is used: protection against physical damage (crushing, puncture, drops), against chemical change (oxygen, which oxidises fat and harms probiotics; light, which causes light-induced off-flavours and destroys riboflavin and vitamin A; moisture gain or loss; and odours from the environment) and against biological contamination (micro-organisms, insects, rodents). Convenience covers ease of opening, pouring, resealing, portioning, microwaving and disposal. Communication carries the information required by law — name, ingredients, nutrition, date marks, net quantity, producer, batch — and marketing messages, brand identity and instructions. Packaging also enables traceability and tamper evidence.
Packaging works at three levels. Primary packaging is in direct contact with the product: the pouch, bottle, carton, cup, wrapper or can. Secondary packaging groups primary packs for handling and retail: shrink-wrapped multipacks, cartons, trays, crates. Tertiary (transport) packaging unitises loads for distribution: pallets, stretch wrap, roll cages. Packaging design must consider the whole system — the product's sensitivity and required shelf life, the filling and sealing process, the distribution chain (chilled, frozen or ambient; distances; handling), the retail environment (lighting, display), consumer use and end-of-life disposal — and the costs and environmental impacts at each step. Under-packaging leads to spoilage and waste, which usually has a far larger environmental cost than the packaging itself; over-packaging wastes material and money. Packaging machines and filling are covered in dairy-processing-equipment, and general food packaging science for the wider food industry in the food technology track's food-packaging; this manual concentrates on dairy needs.
Glass is inert, impermeable to gases and water vapour, transparent or tinted, reusable and recyclable, and gives a premium image; it is heavy, breakable and lets light through unless tinted (amber glass blocks more ultraviolet and short-wavelength light than clear 'flint' glass). Returnable glass milk bottles are still used in some markets, with washing and inspection systems. Metal packaging includes tinplate (steel coated with tin), tin-free steel (chromium-coated) and aluminium; cans are rigid, impermeable to gas, light and moisture, and suit sterilised products such as evaporated and condensed milk, milk powders and infant formula. Internal lacquers protect the metal from the product and the product from the metal; double seams seal can ends, and their integrity is critical. Aluminium foil is used in laminates, lids and butter wrappers for its barrier to light, oxygen and moisture. Paper and paperboard are renewable, printable, light and stiff, but not barriers on their own; for liquids they are coated or laminated with polyethylene, and for fat products with grease-resistant treatments. Parchment and greaseproof papers wrap butter; paperboard forms cartons, cups and secondary packs.
Plastics dominate dairy packaging because they are light, cheap, formable and sealable. Low-density polyethylene (LDPE) and linear LDPE are flexible, tough, heat-sealable and good moisture barriers but poor oxygen barriers; they form milk pouch films and the sealing layers of laminates. High-density polyethylene (HDPE) is stiffer and makes milk bottles and caps. Polypropylene (PP) has a higher melting point, suits hot filling and retorting, and makes cups, tubs and closures. Polystyrene (PS) is easily thermoformed into yoghurt cups but brittle and hard to recycle. Polyethylene terephthalate (PET) is clear, strong and a better oxygen barrier than polyolefins; it makes bottles for milk drinks. Polyvinylidene chloride (PVDC) and ethylene vinyl alcohol (EVOH) are high oxygen-barrier polymers used as thin layers in multilayer films and containers; EVOH loses barrier when wet, so it is sandwiched between moisture-barrier layers. Polyamide (nylon) adds toughness and gas barrier in vacuum and shrink bags. Pigments such as titanium dioxide (white) and carbon black make films opaque to protect milk from light; co-extruded white-black-white pouch films are a common example.
No single material provides every property, so dairy packaging often combines layers. Laminates bond layers with adhesives or by extrusion coating; co-extrusion forms several polymer layers simultaneously. The classic aseptic carton laminate consists of paperboard for stiffness and printing, polyethylene layers for liquid-tightness and sealing, and a thin aluminium foil layer as a barrier to light and oxygen; paperboard makes up the largest share of its mass. Gable-top cartons for chilled milk usually lack the foil layer. Multilayer films for cheese and powders combine a sealing layer (polyethylene), a barrier layer (EVOH, PVDC, metallised film or foil), a strength layer (polyamide or PET) and a print layer. Metallised films (a very thin vapour-deposited aluminium layer on plastic) give good light and gas barrier at low cost. The more complex the structure, the better the protection, but the harder it is to recycle, which is a central tension in modern packaging design.
Packaging materials and finished packs are tested to ensure they meet specifications and perform in use. Basic tests include thickness (micrometres for films), grammage (grams per square metre for paper and board, often called GSM) and dimensions. Mechanical tests include tensile strength and elongation at break (film strength and stretch), tear resistance, puncture resistance, burst strength (paper, board and pouches under internal pressure), impact and drop tests on filled packs, and compression tests on cartons and corrugated boxes, which predict whether stacked loads will collapse. Seal strength tests measure the force needed to peel or break heat seals, and coefficient of friction affects how films run on filling machines. For paper and board, the Cobb test measures water absorption, and grease resistance tests are used for butter wrappers. Glass containers are tested for thermal shock and internal pressure, and cans for double-seam dimensions by tear-down or optical inspection.
Barrier tests measure the oxygen transmission rate (OTR), usually in cubic centimetres of oxygen per square metre per day at a stated temperature and humidity, and the water vapour transmission rate (WVTR), in grams per square metre per day, commonly under tropical conditions of 38 °C and 90 per cent relative humidity; light transmission is measured with spectrophotometers across the ultraviolet and visible range. Integrity tests check finished packs for leaks: dye penetration, bubble emission under vacuum, pressure decay, vacuum decay and, for aseptic packs, incubation of samples and electrolytic or conductivity tests of laminate integrity. Chemical tests include migration testing with food simulants (covered in the migration chapter), odour and taint tests (sensory comparison of product stored with and without the material), residual solvent analysis for printed and laminated films, and identification of polymers by infrared spectroscopy. Tests are run by suppliers, by dairies at goods-in, and in development of new packs; standard methods from ISO, ASTM and national bodies (such as the Bureau of Indian Standards) are used so that results are comparable.
Dairies buy packaging against written specifications that state the material structure, dimensions, thickness or grammage, mechanical and barrier properties, print and colour standards, permitted tolerances, food-contact compliance and packing and labelling of the reels or cartons themselves. New suppliers and new materials are approved after reviewing declarations of compliance with food-contact law, migration and taint test results, trials on the filling line, and storage trials with product. Incoming deliveries are checked against the specification by sampling, and packaging materials are stored clean, dry, protected from pests and odours and used in rotation. Packaging changes, even small ones such as a new ink or adhesive, can introduce taints or affect machine performance, so they are controlled through change management.
Glass and metal are practically impermeable, but polymers allow gases and water vapour to pass through by a solution-diffusion mechanism: molecules dissolve in the polymer at the high-concentration side, diffuse through it, and leave at the other side. The permeability coefficient is the product of solubility and diffusivity. The rate of transmission through a film is proportional to the permeability, the area and the partial pressure difference, and inversely proportional to the thickness: doubling thickness halves transmission. Permeability depends strongly on the polymer: crystalline, polar or tightly packed polymers such as EVOH, PVDC and PET are good oxygen barriers, while polyolefins (polyethylene, polypropylene) are poor oxygen barriers but good water vapour barriers. Temperature raises permeability; humidity raises the oxygen permeability of hydrophilic polymers such as EVOH and polyamide. In multilayer films the resistances of the layers add, so the overall transmission rate T satisfies 1 ÷ T = 1 ÷ T1 + 1 ÷ T2 + …, and the best barrier layer dominates. Pinholes, cracks from flexing, poor seals and closures can let in far more gas than permeation, so pack integrity matters as much as material choice.
Different dairy products need different barriers. Pasteurised milk has a short chilled shelf life, so oxygen barrier is less important than light protection and cost; opaque or pigmented packs protect riboflavin and flavour. UHT milk needs a high oxygen and light barrier for months of ambient storage, hence foil-containing laminates. Whole milk powder and infant formula need very low oxygen and moisture ingress over long shelf lives, hence cans or high-barrier laminates with inert gas. Butter needs grease resistance, light and oxygen barrier and protection from odours. Cheese needs a moisture barrier to stop drying, an oxygen barrier to prevent mould growth on vacuum-packed cheese, and, for some ripening cheeses, permeability to carbon dioxide so that packs do not blow. Probiotic yoghurts benefit from low oxygen permeability to protect bifidobacteria. Shelf life can be estimated from transmission rates: if a pack of 0.05 m² made of a film with an OTR of 10 cm³/m²·day lets in 0.5 cm³ of oxygen per day, and the product can tolerate 10 cm³, it would last about 20 days on oxygen grounds alone — an estimate that must be confirmed by storage trials.
Light is the main cause of rapid quality loss in milk displayed under retail lighting. Riboflavin absorbs light, mainly in the blue and ultraviolet regions, and acts as a photosensitiser that generates reactive oxygen species; these oxidise the amino acid methionine to methional, giving the 'sunlight' or burnt-feather flavour, and oxidise unsaturated lipids, giving cardboard-like flavours, while riboflavin and vitamin A are themselves destroyed. Effects can be noticeable after only hours of exposure in clear packs. Protection comes from opaque materials (paperboard cartons, pigmented HDPE, white-black co-extruded films), pigments such as titanium dioxide that scatter light, light-blocking layers in PET bottles, and amber or tinted glass, as well as from shielding products in display cabinets. Light transmission spectra of packaging are measured to choose materials, since a pack may look opaque but still transmit damaging wavelengths.
Polyethylene pouches are the cheapest and most widely used package for pasteurised milk in South Asia and some other regions. They are made on vertical form-fill-seal machines from rolls of film, usually LDPE/LLDPE blends of several tens of micrometres in thickness, often co-extruded with white and black pigmented layers to block light. The film may be treated with ultraviolet light before forming to reduce surface contamination. Pouch quality depends on film strength and sealability, seal integrity (leakers are a common complaint), fill accuracy, and coding. Pouches use little material per litre, but they are hard to collect and recycle, and many countries now regulate thin plastic films and require producers to take responsibility for them. Milk in pouches still needs an unbroken cold chain.
Bottles for milk are made of glass (returnable in some markets), HDPE (opaque, often with a light barrier) or PET (clear or pigmented); they are filled by gravity, vacuum or volumetric fillers and closed with caps, often with induction-sealed foil liners for tamper evidence and leak prevention. Light protection is a major issue for clear bottles, since retail lighting can cause light-induced off-flavour within hours. Gable-top paperboard cartons, coated with polyethylene, are formed, filled and sealed on carton machines in clean or ultra-clean conditions and suit pasteurised and ESL milk; ESL cartons may include an extra barrier layer. Brick-shaped aseptic cartons are used for UHT milk (next chapter). The choice of pack depends on product, shelf life, market expectations, cost, existing filling equipment and end-of-life rules. Filling machinery is described in dairy-processing-equipment.
Aseptic packaging fills a commercially sterile product into sterile containers in a sterile environment and seals them hermetically, so that the product keeps without refrigeration. It is used for UHT milk, cream, flavoured milks, dairy desserts and liquid infant formula. It requires: sterilisation of the product (by UHT, covered in market-milk-processing); sterilisation of the packaging material or containers; sterilisation of the filler before production; maintenance of sterility during filling (sterile zone under filtered sterile air overpressure); and hermetic seals. Unlike in-container sterilisation, the package is not heated with the product, so heat-sensitive, lightweight packaging such as paperboard laminates and thin plastics can be used, and the product suffers less heat damage.
The most common sterilant for packaging material is hydrogen peroxide, typically at a concentration of around 30–35 per cent, applied by passing web material through a bath or spraying or vaporising it onto preformed containers, followed by hot sterile air to activate the peroxide and evaporate the residue. Residual hydrogen peroxide in filled packs is limited by regulations (in the United States, for example, a very low residual limit applies) and is monitored. Other methods include peracetic acid (for PET bottles), saturated steam for heat-resistant containers, ultraviolet light (alone it is limited to surface treatment and is often combined with peroxide), and electron-beam irradiation of preforms and material, which avoids chemical residues. Aseptic systems are validated with biological indicators (spores of resistant organisms such as Bacillus atrophaeus or Geobacillus stearothermophilus) to show the required log reduction. In production, commercial sterility is checked by incubating a sample of packs and examining them for swelling, pH change and microbial growth, and by testing seals and laminate integrity.
Retort pouches are flexible laminated pouches — typically polyester for strength, aluminium foil or a transparent high-barrier layer, and cast polypropylene as the heat-resistant sealing layer — that withstand sterilisation in overpressure retorts. They heat and cool faster than cans because they are thin, so they give less heat damage, and they are lighter to transport; they are used for dairy desserts, ready meals with dairy ingredients, and canned-style traditional sweets such as rasogolla or gulab jamun in syrup, as well as paneer-based curries. Microwavable packaging uses polypropylene, crystalline PET or paperboard trays that withstand microwave heating without melting, with design features (vents, susceptors that brown food surfaces) for even heating; metal is avoided except in specially designed packs. Edible films and coatings — made from milk proteins (caseinates, whey protein), polysaccharides or lipids — are studied as moisture or oxygen barriers on cheese and other foods; wax and polymer coatings on cheese are an established form of protective coating, though not eaten. Biodegradable materials such as polylactic acid are used for some cups and films where suitable disposal exists.
Butter needs protection from light and oxygen (which cause oxidised and tallowy flavours), from loss of moisture at the surface, from absorption of odours, and from grease seepage. Traditional parchment and greaseproof wrappers have largely been replaced or supplemented by aluminium foil laminated to paper, which gives a much better light and oxygen barrier; spreadable butter and blends are packed in polypropylene tubs with lids and sometimes foil seals. Bulk butter is packed in lined cartons for cold storage. Cheese packaging depends on the type. Hard and semi-hard cheeses for ripening are vacuum-packed in barrier bags or heat-shrink bags (often with PVDC or EVOH barrier layers) that prevent mould growth and moisture loss; some ripening films are deliberately permeable to carbon dioxide so packs do not swell. Gouda-type cheeses may be coated with wax or plastic coatings during ripening. Sliced and grated cheese uses modified atmosphere packs with carbon dioxide and nitrogen, often in thermoformed trays. Soft and mould-ripened cheeses need packs that allow some gas exchange and protect a delicate rind; fresh cheeses and paneer use vacuum packs or tubs; brined cheeses are packed in brine in tins or plastic containers.
Milk powders need protection from moisture (to prevent caking and browning) and, for whole milk powder and infant formula, from oxygen. Bulk powders are packed in multiwall paper bags with a polyethylene liner or in large bulk bags; retail powders and infant formula go into cans or high-barrier laminate pouches and bag-in-box packs, flushed with nitrogen or nitrogen–carbon dioxide to reduce residual oxygen. Ice cream packaging must withstand frozen storage, condensation during thawing and handling, and give insulation and convenience: coated paperboard cartons and cups, plastic tubs, wrappers for stick novelties, and sleeves for cones; packs must limit moisture loss that causes surface desiccation (freezer burn) and absorb as little odour as possible. Fermented milks are filled into polystyrene or polypropylene cups (preformed or thermoformed on form-fill-seal machines) sealed with foil or plastic lids, or into bottles for drinks; for probiotic products, low oxygen permeability and light protection improve survival. Packs for kefir must cope with gas production. Traditional products in South Asia are packed in earthen pots, cups, trays and cans; canned rasogolla and gulab jamun in syrup are retorted.
Dairy products exported over long distances or sold in hot, humid climates face harsher conditions than those in temperate home markets. Powders and condensed milks may spend months in containers and warehouses at high temperature and humidity, so packs need higher moisture and oxygen barriers, robust seams and seals, and outer packaging that resists humidity and handling. Labels must meet the importing country's language and regulatory requirements. Shelf-life studies for these markets are run at elevated temperature and humidity, and packaging is chosen on the basis of measured performance under those conditions rather than home-market experience.
Vacuum packaging removes air from the pack before sealing, so that the film collapses onto the product. It limits aerobic spoilage organisms such as moulds and slows oxidation, and is widely used for cheese blocks, paneer, cheese portions and some butter products. Shrink packaging uses bags or films that shrink tightly around the product when heated briefly (in hot water or hot air) after vacuum sealing, giving an attractive, tight, wrinkle-free pack with fewer channels where moisture and moulds can collect; shrink bags for ripening cheese usually include a gas-barrier layer. Barrier properties, seal quality and puncture resistance are critical, because a single pinhole lets oxygen in and moulds grow under the film. Vacuum packs are not suitable for soft, crumbly or delicate products that would be crushed, or for products whose quality depends on gas exchange.
Modified atmosphere packaging (MAP) replaces the air in a pack with a chosen gas mixture before sealing. For dairy products the main gases are carbon dioxide, which inhibits many bacteria and moulds by dissolving into the product's water and fat phases and lowering pH at the surface, and nitrogen, an inert filler that prevents pack collapse and displaces oxygen. Oxygen is kept as low as possible. Typical uses are sliced, grated and shredded cheese, cottage cheese, some fresh cheeses, dairy desserts and cream-filled products. Because carbon dioxide dissolves into the product, packs can collapse if the CO2 proportion is too high, so a balance with nitrogen is used, and the ratio of gas volume to product volume (headspace) is designed to give enough CO2. MAP needs high-barrier packaging to keep the atmosphere stable over the shelf life, good seals, and chilled storage; it extends shelf life but does not replace good hygiene and temperature control. Gas composition is checked with headspace analysers on the line.
Active packaging interacts with the product or its headspace to extend shelf life or improve quality, rather than acting only as a passive barrier. Oxygen scavengers — iron-based sachets or labels, or oxygen-absorbing polymers built into films and closures — remove residual oxygen and oxygen that permeates in, protecting fat from oxidation and helping probiotic survival; they are used in some powders, cheese packs and dairy drinks. Moisture absorbers (desiccant sachets) protect powders and tablets; carbon dioxide absorbers help coffee and some fermented products, and carbon dioxide emitters support MAP. Antimicrobial packaging releases or carries agents that inhibit micro-organisms on the product surface: natamycin, an antifungal, is applied to cheese coatings and surfaces in many countries within legal limits, and antimicrobial films with bacteriocins, essential oils or silver have been studied. Active packaging must comply with food-contact rules for active materials, which in the European Union are specifically regulated, and any substance released into food must be permitted as a food additive.
Intelligent (smart) packaging monitors and communicates the condition of the product or its environment. Time-temperature indicators (TTIs) are labels that change colour irreversibly according to the cumulative time and temperature they experience, through chemical, enzymatic or microbial reactions calibrated to match the product's spoilage kinetics; they show whether a chilled or frozen product has been abused. Freshness indicators respond to compounds produced by spoilage (such as carbon dioxide or acids), and gas indicators show whether a MAP pack has leaked (an oxygen indicator changes colour if oxygen enters). Data carriers such as barcodes, QR codes and radio-frequency identification (RFID) tags support traceability, stock control and consumer information, and some sensors log temperature through the supply chain. Intelligent packaging is still used mainly in higher-value or export products because of cost, but its role in cold-chain management and waste reduction is growing. The reliability of indicators depends on calibration against the specific product and on consumers understanding them.
Whether active or intelligent packaging is worthwhile depends on the product's value, its main deterioration mechanism and the cost of the device compared with the value of the shelf-life gain or waste reduction. An oxygen scavenger makes sense for a high-value powder or a probiotic product limited by oxygen, but not for pasteurised milk limited by microbial growth. A time-temperature indicator is useful where cold-chain abuse is the main risk and someone will act on the signal. Regulatory approval, consumer acceptance, recyclability and the risk of a sachet being swallowed or mistaken for food also enter the decision.
Substances can move from packaging into food — monomers, oligomers, additives (plasticisers, antioxidants, slip agents), printing inks, adhesives, coating components and contaminants from recycled materials. Migration is faster into fatty foods, at higher temperatures and over longer contact times, which makes dairy products such as cheese, butter and cream demanding for packaging safety. Regulations control migration in two ways. Overall migration limits restrict the total amount of substances that may migrate, measured with food simulants under standard test conditions (in the European Union, for example, an overall migration limit of 10 mg per dm² of contact surface, or 60 mg per kg of food, applies to plastics). Specific migration limits restrict individual substances of concern, based on toxicological evaluation. Food simulants represent food types: aqueous, acidic, alcoholic and fatty simulants (such as dilute ethanol solutions, dilute acetic acid and vegetable oil or 95 per cent ethanol for fatty foods), with milk and many dairy products assigned specific simulants under the rules.
Food-contact materials are regulated in all major markets. In the European Union, a framework regulation requires that materials do not transfer constituents to food in quantities that endanger health or change the food's composition, taste or smell unacceptably, with specific rules for plastics, good manufacturing practice, and recycled plastics. In the United States, the Food and Drug Administration regulates food-contact substances, with listings in the Code of Federal Regulations and a notification system. India's Food Safety and Standards (Packaging) Regulations set requirements for packaging materials, referring to Indian Standards for many materials, and prohibit some practices such as wrapping food in newspaper. Concerns that drive regulation and industry choices include bisphenol A in can coatings and polycarbonate, phthalate plasticisers, mineral oil hydrocarbons from recycled paperboard and inks, printing ink set-off (transfer of ink from the printed outside to the food-contact side when films are reeled), primary aromatic amines from some adhesives, and contaminants in recycled plastics, which may be used for food contact only through approved recycling processes. Dairies manage this through supplier declarations of compliance, migration testing, taint testing and good handling of packaging materials.
Packaged dairy products must carry information required by food law, which in most countries follows the Codex General Standard for the Labelling of Prepackaged Foods, with national variations. Typical requirements are: the name of the food, using the legally defined name where one exists (for example a standardised name such as toned milk, cheddar cheese or ice cream, and qualified names such as 'frozen dessert' for vegetable-fat products in India); the list of ingredients in descending order of weight, with additives identified; declaration of allergens, with milk itself an allergen to be declared when used as an ingredient; net quantity under legal metrology rules; date marking ('use by' for perishable products where safety is at stake, 'best before' for quality); storage conditions and instructions for use; the name and address of the manufacturer or packer; lot or batch identification; and country of origin where required. In India, labelling is governed by the FSS (Labelling and Display) Regulations, with the FSSAI logo and licence number and the vegetarian symbol, and net quantity by the Legal Metrology (Packaged Commodities) Rules.
Nutrition labelling declares energy and nutrients per 100 g or 100 mL (and often per serving): commonly energy, protein, carbohydrate (with sugars and, in many countries, added sugars), fat (with saturated and sometimes trans fat), and sodium or salt, with vitamins and minerals when claims are made or when they are present at significant levels. Energy is calculated from conversion factors: 4 kcal per gram of protein and of carbohydrate and 9 kcal per gram of fat (with other factors for alcohol, polyols and fibre in some countries). For example, milk with 3.0 per cent fat, 3.2 per cent protein and 4.7 per cent carbohydrate provides about 4 × 3.2 + 4 × 4.7 + 9 × 3.0 ≈ 59 kcal per 100 mL. Nutrition and health claims — such as 'high protein', 'low fat', 'source of calcium' or 'contains probiotics' — must meet defined conditions in each jurisdiction, and some health claims require prior approval. Front-of-pack schemes (traffic lights, warning labels, star ratings) are being adopted or debated in several countries, and dairy products' scores depend on fat, saturated fat, sugar and sodium. Labels must not mislead, for example by implying that an analogue is a dairy product.
Every pack is coded with a lot or batch number and date mark, printed by inkjet, laser or thermal transfer printers on the filling line, and these codes link the pack to production records for traceability and recall. Codes must be legible, durable and correctly placed; code verification systems check them automatically. Secondary and tertiary packaging — crates, shrink-wrapped trays, corrugated cases, pallets and stretch wrap — must protect primary packs during handling, stacking and transport, resist moisture in cold stores, and carry labels with product, quantity, batch and dates, often with barcodes or RFID for warehouse systems. Returnable plastic crates for milk pouches and bottles are washed and inspected between uses. Load stability and compression strength are designed for the stacking height and humidity of cold stores, since corrugated board loses much of its strength in humid conditions.
Dairy packaging generates large volumes of waste, much of it plastic and multilayer material that is difficult to recycle. Milk pouches, yoghurt cups, multilayer laminates, foil-paper wrappers and aseptic cartons each pose specific problems: thin films are light, often contaminated with milk and of low scrap value, so they are rarely collected; polystyrene cups are recyclable in principle but seldom recycled; multilayer laminates combine materials that are hard to separate. Aseptic cartons can be recycled in paper mills, where hydropulping recovers the paper fibre, leaving a polyethylene–aluminium residue that needs further processing. Glass and metal have established recycling streams. Poorly managed packaging pollutes land, rivers and oceans, and burning it releases harmful emissions. At the same time, packaging prevents food waste, so the goal is better packaging, not simply less.
Strategies include designing for recycling (mono-material packs such as all-polyethylene or all-polypropylene structures with thin barrier coatings instead of mixed laminates, avoiding carbon black pigments that defeat optical sorting, using compatible labels and inks), light-weighting (thinner bottles and films), using recycled content where approved for food contact, returnable and refillable systems (glass bottles, bulk dispensers), and bio-based or compostable materials where the infrastructure exists to handle them. Life-cycle assessment compares options over raw materials, manufacture, transport, use and end of life, and often shows that the product inside has a much larger footprint than the pack. Extended producer responsibility (EPR) makes producers, importers and brand owners responsible for the collection and recycling of the packaging they place on the market. In India, the Plastic Waste Management Rules and their amendments require brand owners to register and meet EPR targets for collection, recycling and use of recycled content for different categories of plastic packaging, and ban certain single-use items. The European Union has a regulation on packaging and packaging waste with recyclability, recycled-content and reuse requirements, and many other countries have deposit schemes or EPR laws. Recycling rate is calculated as the mass recycled divided by the mass placed on the market.
A student uses this subject to choose materials for each dairy product, explain barrier needs, calculate oxygen ingress and multilayer transmission, estimate energy for nutrition labels, and describe aseptic packaging, MAP and active and intelligent packaging. It supports AICE Dairy Technology Unit 2 and AIEEA-PG group 17 questions.
A packaging or quality technologist five years in specifies films, cartons and closures, approves suppliers with migration and taint data, tests incoming materials, investigates leakers, light-struck flavour and blown packs, sets up MAP and vacuum packing, checks labels against regulations, and reports EPR data. This subject gives the knowledge behind those tasks.
A plant head or packaging director decides on pack formats and materials for new products, investment in aseptic and filling lines, sustainability strategy (recyclability, recycled content, returnables), and compliance with labelling and EPR rules across markets.
A professor or research director works on barrier materials, active and intelligent packaging, migration science, recyclable high-barrier structures, and shelf-life modelling. They examine AICE Dairy Technology Unit 2 and advise industry and regulators on packaging safety and sustainability.
This manual does not yet give: current numeric limits for specific migration, residual hydrogen peroxide, and nutrition and health claims in each country; detailed EPR targets by plastic category; full standard test methods; detailed retort pouch and microwavable packaging technology; and packaging machine engineering (in dairy-processing-equipment). Film thicknesses, sterilant concentrations and barrier values are representative and must be confirmed with suppliers and current regulations.
Original practice questions written to the syllabus and pattern of the exams named in each question's examTags. They are not past papers and do not reproduce any board's questions.
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