Dairy Science & Technology · Dairy Processing & Product Technology · also Infant Foods, Speciality Dairy Foods
Formulating and manufacturing infant formula, follow-on, medical and sports nutrition products from milk, under the strictest standards in the dairy industry.
In the exams: ICAR AICE subject 37 Unit 6 and subject 34 Unit 6 (infant food); ICAR AIEEA-PG groups 16 and 17
Infant formula is the most demanding product the dairy industry makes. It may be the sole source of nutrition for a baby in the first months of life, when the infant is most vulnerable to nutrient imbalance, contamination and allergy. It must therefore be formulated to standards set in detail by Codex and national law, made in plants with the strictest hygiene in food manufacturing, tested against microbiological criteria that tolerate no Salmonella or Cronobacter, and sold under marketing rules that protect breastfeeding. Alongside infant formula, the same plants and the same science produce follow-on formulas, products for young children, hydrolysed and amino-acid formulas for allergic infants, foods for special medical purposes, enteral feeds, and sports and elderly nutrition products based on milk proteins.
This manual starts with human milk, the reference against which every infant formula is judged. It then covers the Codex and national standards, the formulation of protein, fat, carbohydrate and micronutrients, the wet-mix, dry-blend and hybrid processes, and the control of Cronobacter and Salmonella in powder plants. It treats hydrolysed and amino-acid formulas, human milk oligosaccharides and other novel ingredients, follow-on formulas, growing-up milks and the marketing rules that govern them, medical and enteral nutrition, and sports and elderly nutrition.
Breastfeeding is the recommended way to feed infants: the World Health Organization recommends exclusive breastfeeding for the first six months and continued breastfeeding with complementary foods to two years or beyond. Infant formula is needed when breastfeeding is not possible, not chosen or not sufficient, and then it must be as safe and as close to the reference as science allows. Doctoral fellowship examinations in dairy technology and dairy chemistry include infant foods as a named unit, and postgraduate entrance examinations ask about human milk composition, formulation, manufacture and safety. Industry roles in infant and medical nutrition demand this knowledge at a professional level.
Human milk changes through lactation. Colostrum, produced in the first few days, is rich in protein, especially secretory immunoglobulin A and lactoferrin, and lower in fat and lactose. Transitional milk follows, and mature milk is established after about two weeks. Mature human milk typically provides about 65 to 70 kcal per 100 mL, with roughly 0.9 to 1.2 g of protein, 3.5 to 4 g of fat and about 7 g of lactose per 100 mL. Composition also varies within a feed, as hindmilk is richer in fat than foremilk, between times of day and between mothers, and the fatty acid profile reflects the mother's diet.
Compared with cow milk, human milk has much less protein (cow milk has about 3.3 g per 100 mL), more lactose (cow milk about 4.8 g), and far less mineral, about a third as much, which together give it a low renal solute load suitable for the immature infant kidney. The protein is mainly whey: the whey-to-casein ratio is high in early milk and commonly cited as about 60:40 in mature milk, whereas cow milk is about 20:80. Human whey contains no β-lactoglobulin; its main proteins are α-lactalbumin, lactoferrin, secretory IgA and lysozyme, which have nutritional, antimicrobial and immune functions. Human casein is mainly β-casein, forming smaller, looser micelles that make a soft curd in the stomach.
Human milk fat is about 98% triglyceride. Around 70% of its palmitic acid is esterified at the sn-2 position of the glycerol, whereas in vegetable oils palmitic acid is mostly at the outer positions. This matters because pancreatic lipase releases fatty acids from the sn-1 and sn-3 positions: palmitic acid at sn-2 is absorbed as a monoglyceride, while free palmitic acid released from the outer positions can form insoluble calcium soaps that reduce fat and calcium absorption and harden stools. Human milk also contains the long-chain polyunsaturated fatty acids docosahexaenoic acid (DHA) and arachidonic acid (ARA), cholesterol, and the milk fat globule membrane.
After lactose and fat, the third largest solid component of human milk is human milk oligosaccharides, about 5 to 15 g per litre in mature milk and more in colostrum, compared with only traces in cow milk. More than 150 structures have been identified. They are built on lactose and include fucosylated forms such as 2′-fucosyllactose, sialylated forms such as 3′- and 6′-sialyllactose, and neutral core structures such as lacto-N-tetraose. Their pattern depends on the mother's genes: mothers with an active FUT2 gene, called secretors, produce abundant 2′-fucosyllactose, while non-secretors produce little.
Human milk oligosaccharides are not digested by the infant. They reach the colon, where they selectively feed bifidobacteria, especially Bifidobacterium longum subsp. infantis; they act as soluble decoy receptors that block the attachment of pathogens to the gut wall; and they modulate immune development. Human milk also contains living cells, antibodies, enzymes such as bile salt-stimulated lipase, hormones, growth factors, nucleotides and a microbiota of its own.
No formula can reproduce all of this. Formula development therefore aims at two targets: matching the composition of human milk where that is known to matter, and matching the outcomes of breastfed infants, such as growth patterns, stool characteristics, infection rates, gut microbiota and developmental scores. Because human milk varies so much, composition targets are ranges rather than single values, and a new ingredient is justified only by evidence that it brings formula-fed infants' outcomes closer to those of breastfed infants without harm.
The Codex Standard for Infant Formula and Formulas for Special Medical Purposes Intended for Infants (CXS 72-1981, revised in 2007) is the international reference. It defines infant formula as a breast-milk substitute specially manufactured to satisfy, by itself, the nutritional requirements of infants during the first months of life up to the introduction of appropriate complementary feeding. Its compositional requirements are expressed per 100 kcal, so that they apply whatever the dilution.
Prepared ready for consumption, infant formula must provide 60 to 70 kcal per 100 mL. For formula based on cow milk protein, protein must be 1.8 to 3.0 g per 100 kcal, calculated as nitrogen multiplied by 6.25. Fat must be 4.4 to 6.0 g per 100 kcal, with minimum linoleic acid of 300 mg per 100 kcal, minimum α-linolenic acid of 50 mg per 100 kcal, and a linoleic to α-linolenic ratio between 5:1 and 15:1. Lauric and myristic acids together must not exceed 20% of fat, trans fatty acids 3% and erucic acid 1%. Carbohydrate must be 9.0 to 14.0 g per 100 kcal, with lactose and glucose polymers preferred. If DHA is added, ARA must be at least equal to it and DHA must not exceed 0.5% of fatty acids. The standard sets minimum and maximum or guidance upper levels for every vitamin and mineral, and requires that formulas meet the essential amino acid pattern of human milk protein.
The standard also controls ingredients and processing: optional ingredients must be shown to be safe and suitable for the particular nutritional use by generally accepted scientific evidence; food additives are limited to a short positive list; and the product must be produced under the Codex hygiene codes. Labels must carry statements on the superiority of breastfeeding, preparation instructions and warnings, and must not idealise formula.
Countries adopt the Codex standard directly or write their own rules, which are often stricter or more detailed. In the European Union, a 2016 delegated regulation sets protein for cow-milk-based infant formula at 1.8 to 2.5 g per 100 kcal, makes DHA mandatory at 20 to 50 mg per 100 kcal, and lays down rules on pesticide residues and labelling. In the United States, infant formula is regulated by the Food and Drug Administration under a dedicated law, with nutrient specifications, current good manufacturing practice rules specific to infant formula, quality-control testing, and a requirement to notify the agency before marketing a new formula. China, Australia and New Zealand, the Gulf states, South and South-East Asian countries, and others have their own standards, product registration schemes or both; China, for example, requires registration of each formula recipe.
Key differences between jurisdictions concern protein ranges, mandatory or optional ingredients such as DHA, permitted novel ingredients, microbiological criteria, the age ranges and composition of follow-on formulas, labelling and claims, and marketing restrictions. An exporter must meet the destination's rules, which may require registration of the plant and of each recipe, specific labelling in the local language and testing at import.
Standards are reviewed as science advances. Expert bodies periodically reassess nutrient requirements, upper limits and new ingredients, and the Codex standard for follow-up formula was revised in 2023 to define follow-up formula for older infants and products for young children. Technologists must track these revisions, because a change in a minimum or maximum level can require reformulation across a product range.
Most infant formulas are based on cow milk protein; others use goat milk, soy protein isolate or hydrolysed proteins. Because cow milk has about four times as much casein relative to whey as human milk, formulators blend skim milk with whey protein sources to raise the whey proportion. Demineralised whey powders, from which most minerals have been removed by electrodialysis, ion exchange or nanofiltration, are essential, because ordinary whey would give a mineral load far above the infant's needs. Whey protein concentrates, and fractions enriched in α-lactalbumin, allow total protein to be lowered while still meeting the essential amino acid requirements, because α-lactalbumin is rich in tryptophan and cysteine. Lower protein intakes in formula-fed infants are associated with growth closer to that of breastfed infants.
The blend calculation is a simple mass balance. If skim milk protein is 80% casein and 20% whey, and a whey protein ingredient is all whey, then to reach a whey-to-casein ratio of 60:40, the whey fraction of total protein must satisfy 0.2x + y = 0.6(x + y), where x and y are the protein contributed by skim milk and by whey; this gives y = x, so half the protein must come from each source.
Lactose is the preferred carbohydrate, as in human milk; it supplies energy, aids calcium absorption and supports a bifidobacteria-rich microbiota. Lactose-reduced and lactose-free formulas, used in specific situations, replace it with glucose polymers such as maltodextrin. Codex limits the use of sucrose and fructose, and precooked or gelatinised starch can be used within limits.
The fat of infant formula is usually a blend of vegetable oils designed to approach the fatty acid profile of human milk: palm olein or palm oil for palmitic acid, coconut or palm kernel oil for lauric and myristic acids, high-oleic sunflower or safflower oil for oleic acid, soybean or sunflower oil for linoleic acid and rapeseed oil for α-linolenic acid. Milk fat is increasingly used, alone or blended, for its short- and medium-chain fatty acids, cholesterol and sn-2 palmitate. DHA comes from fish oil or algal oil and ARA mainly from fungal oil.
The position of palmitic acid matters. In palm-based blends most palmitate is at the outer positions; after digestion it is released as free fatty acid that can form calcium soaps, reducing fat and calcium absorption and making stools harder. Structured lipids with palmitic acid at sn-2 and oleic acid at sn-1 and sn-3, known as OPO, are made by enzymatic interesterification of tripalmitin-rich fat with oleic acid using sn-1,3-specific lipases, and mimic human milk fat. Fat ingredients must be fresh and well protected from oxidation, because long-chain polyunsaturated fatty acids oxidise easily; antioxidants such as tocopherols and ascorbyl palmitate are used.
Micronutrients are added as a vitamin premix and a mineral premix, dosed precisely and checked by analysis. Choices include iron as ferrous sulphate, calcium and phosphorus at a ratio between about 1:1 and 2:1, zinc, copper, iodine, selenium, and all vitamins. Overages compensate for losses during processing and shelf life, especially of vitamins A, C and some B vitamins, but must keep the product below upper limits throughout. Optional ingredients include nucleotides, lutein, carnitine, taurine, inositol, prebiotic oligosaccharides and probiotics. A worked energy check is routine: a formula with 1.3 g protein, 3.5 g fat and 7.3 g carbohydrate per 100 mL gives 1.3 × 4 + 3.5 × 9 + 7.3 × 4 = 65.9 kcal, with protein at 1.3/0.659 ≈ 2.0 g per 100 kcal.
In the wet-mix process all or most ingredients are combined in liquid form, heat treated, homogenised, concentrated and spray dried. Milk, whey concentrates and lactose solutions are mixed with the oil blend, which is dosed with fat-soluble vitamins and emulsifiers, and with water-soluble minerals and vitamins, under careful control of order of addition, temperature and pH to avoid protein destabilisation and mineral precipitation. The mix is heat treated to destroy vegetative pathogens, homogenised to form a fine, stable emulsion, evaporated to a high solids concentration in a falling-film evaporator, often with a further heat treatment, and spray dried.
Spray drying for infant formula uses multi-stage dryers with an integrated or external fluid bed, which dry gently, cool the powder and allow agglomeration for good wettability and dispersibility; lecithin may be sprayed on to improve wetting. The powder leaves at low moisture, typically about 2 to 3%, with water activity well below 0.3, and is cooled and sieved. Some is packed directly; some becomes base powder for later dry blending.
The wet-mix route gives the most homogeneous product: every particle has nearly the same composition, the fat is fully emulsified and encapsulated, and the heat treatment acts on all ingredients. Its disadvantages are high energy use, heat exposure of sensitive ingredients, long cleaning cycles and less flexibility to change recipes. Liquid ready-to-feed and concentrated liquid formulas follow the same mixing and homogenisation steps but are then sterilised in the container or by UHT treatment and aseptic filling.
In the dry-blend process, pre-made powders such as base powders, skim milk powder, demineralised whey powder, lactose, fat-filled powders, vitamin and mineral premixes and sensitive ingredients are weighed and mixed in a dry blender. It uses less energy and allows quick recipe changes and the addition of heat-sensitive ingredients such as probiotics. Its weaknesses are that the final product receives no further kill step, so every ingredient must already be microbiologically safe and the blending area must be kept very hygienic; that powders of different particle size and density can segregate in handling, so homogeneity must be validated; and that micronutrient distribution depends on blending performance.
Hybrid processes combine the two: a base powder containing protein, fat and most minerals is made by wet mixing and spray drying, and lactose, some vitamins and minerals, oligosaccharides, probiotics and other ingredients are dry blended into it. Most large plants use some form of hybrid process.
Packing protects the powder. Infant formula is filled into metal cans or composite containers, or into laminated bags in boxes, flushed with nitrogen or a nitrogen-carbon dioxide mixture to reduce residual oxygen to a few per cent, which slows oxidation of polyunsaturated fats and vitamins. Each batch is tested for composition, micronutrients, contaminants and microbiology before release, and full traceability from ingredient lots to finished cans is maintained so that any problem can be traced and recalled quickly.
Powdered infant formula is not sterile. Although the wet mix is heat treated, organisms can enter after drying, from the plant environment, equipment, air, ingredients added by dry blending and packaging. Two pathogens are of greatest concern. Cronobacter species, formerly classified as Enterobacter sakazakii, are Gram-negative members of the Enterobacteriaceae that survive drying and long storage in powders. They rarely cause illness, but in neonates, especially preterm, low-birth-weight and immunocompromised infants under two months of age, they can cause meningitis, septicaemia and necrotising enterocolitis with high fatality. Salmonella, which also survives in dry foods for long periods, has caused outbreaks linked to infant formula.
Because the dose needed to cause illness in vulnerable infants may be low and the organisms can multiply rapidly once formula is reconstituted and held warm, the industry and regulators treat their presence as unacceptable. The Codex Code of Hygienic Practice for Powdered Formulae for Infants and Young Children (CXC 66-2008) sets microbiological criteria for powdered infant formula: Cronobacter must be absent in each of 30 samples of 10 g (n = 30, c = 0, m = 0 per 10 g), and Salmonella absent in each of 60 samples of 25 g (n = 60, c = 0, m = 0 per 25 g). Enterobacteriaceae and mesophilic aerobic counts are used as process hygiene indicators. Even such intensive testing cannot prove absence in a whole batch, so safety depends on prevention.
Control starts with the design of the plant. Areas are zoned by hygiene level, with the high-hygiene dry zone, where powder is exposed after drying, physically separated and supplied with filtered air at positive pressure. People, materials and air move from cleaner to less clean areas, not the reverse. The dry zone is kept dry: water is the main enabler of Enterobacteriaceae growth, so dry cleaning by vacuuming and brushing is used wherever possible, and wet cleaning is done only under control and followed by thorough drying. Condensation and leaks are repaired immediately. Equipment is designed to avoid crevices and powder deposits.
An environmental monitoring programme samples surfaces, floors, drains, air and equipment, especially in the dry zone, for Enterobacteriaceae and Cronobacter, with trend analysis and corrective actions; positive findings trigger investigation and intensified cleaning, and close-to-product findings may lead to holding product. Ingredients added after the heat treatment must come from approved suppliers with equivalent controls and be tested. Finished product is tested before release against the Codex criteria and any stricter customer or national limits.
Safe preparation completes the chain. WHO and FAO guidance advises that powdered formula be reconstituted with water at no less than 70 °C, which kills Cronobacter that may be present, then cooled quickly and fed promptly, with leftovers discarded and prepared formula not held for long at room temperature. For high-risk infants in hospitals, sterile liquid formulas are preferred. Labels carry preparation instructions and warnings.
Cow milk protein allergy is one of the commonest food allergies of infancy, affecting a few per cent of infants, most of whom outgrow it in early childhood. It may be IgE-mediated, with rapid reactions such as urticaria, vomiting and rarely anaphylaxis, or non-IgE-mediated, with delayed gastrointestinal and skin symptoms. Both casein and whey proteins, especially β-lactoglobulin, can be allergens. For a formula-fed infant with the allergy, a formula is needed in which the protein no longer provokes reactions.
Hydrolysed formulas are made by digesting milk proteins with proteolytic enzymes, such as pancreatic enzymes or microbial proteases, under controlled temperature and pH, often followed by heat treatment and by ultrafiltration to remove residual intact protein and large peptides. The extent of hydrolysis is followed by the degree of hydrolysis, the percentage of peptide bonds cleaved, DH = h/htot × 100, where h is the number of bonds hydrolysed and htot the total per gram of protein; a hydrolysate with h = 2.2 meq/g from a protein with htot = 8.8 meq/g has DH = 25%. The peptide size distribution is measured by chromatography.
Partially hydrolysed formulas contain larger peptides; they are not suitable for treating cow milk protein allergy, and the evidence for their use in allergy prevention is debated. Extensively hydrolysed formulas, of casein or whey, contain mainly small peptides and are used as the first-line treatment for most infants with the allergy. A widely used criterion defines a hypoallergenic formula as one tolerated by at least 90% of infants with documented cow milk allergy, with 95% confidence, in clinical challenge studies.
Amino-acid-based formulas contain no peptides: their nitrogen comes entirely from free amino acids, so they are non-allergenic. They are used for infants who react to extensively hydrolysed formula, for severe or multiple food allergies, eosinophilic oesophagitis and some cases of severe allergy with growth failure. They are more expensive, and free amino acids raise the osmolality and give a distinct taste.
Hydrolysis creates technical problems. Hydrophobic peptides taste bitter, which matters less for infants than for older children but affects acceptance; enzymes and conditions are chosen to limit bitterness. Hydrolysates lose the emulsifying and heat-stability properties of intact proteins, so emulsions need other emulsifiers. Peptides and free amino acids take part readily in Maillard reactions with reducing sugars, which is why many hydrolysed and amino-acid formulas use glucose polymers rather than, or with less, lactose, and need careful heat treatment.
Other alternatives include soy protein formulas, which are not recommended in the first six months in some guidelines and are not suitable for infants with non-IgE soy cross-reactivity, and hydrolysed rice protein formulas, used in some regions. Goat milk formulas are not suitable for cow milk allergy because goat and cow milk proteins cross-react strongly. Lactose-free formulas address lactose intolerance, which is different from milk protein allergy. Hydrolysed formulas are also used in formulas for preterm infants and in enteral products to improve tolerance and absorption.
For decades, the oligosaccharide gap between human milk and formula was addressed with prebiotic mixtures of short-chain galacto-oligosaccharides, made from lactose by β-galactosidase, and long-chain fructo-oligosaccharides from inulin, typically in a 9:1 ratio. These stimulate bifidobacteria but are not structurally identical to human milk oligosaccharides.
Since the mid-2010s, individual human milk oligosaccharides identical in structure to those in human milk have become available commercially, made mainly by fermentation with engineered microorganisms or by enzymatic synthesis and then purified. The first and most abundant is 2′-fucosyllactose; others include lacto-N-neotetraose, lacto-N-tetraose, 3-fucosyllactose and the sialyllactoses 3′-SL and 6′-SL. They are approved as novel foods or by equivalent safety evaluations in many jurisdictions, at specified maximum levels in infant formula and other foods, and the levels used are typically a fraction of total human milk oligosaccharide content of breast milk, often around 1 to 2 g per litre in total.
Clinical studies show that formulas with these oligosaccharides support normal growth and shift stool consistency and gut microbiota towards those of breastfed infants, and some report fewer infections or immune markers closer to breastfed infants, though the size and consistency of benefits are still being established. Because human milk oligosaccharide patterns vary with the mother's secretor status, there is no single 'correct' profile to copy.
Several other dairy-derived components are added to bring formula closer to human milk. Milk fat globule membrane concentrates, from whey or buttermilk, supply phospholipids, sphingomyelin, gangliosides and membrane proteins associated with neurodevelopment and infection protection in some trials. Bovine lactoferrin, isolated from milk or whey by cation-exchange chromatography, binds iron and has antimicrobial activity. α-Lactalbumin-enriched whey protein concentrates allow lower protein formulas. Osteopontin, a phosphorylated glycoprotein abundant in human milk, is available from bovine milk. sn-2 palmitate structured lipids, discussed earlier, are another example. Nucleotides, lutein, DHA and ARA are long-established additions.
Probiotics, live microorganisms such as strains of Bifidobacterium animalis subsp. lactis, Lacticaseibacillus rhamnosus and Limosilactobacillus reuteri, are added to some formulas; they must be added after heat treatment, usually by dry blending, and their counts must be maintained through shelf life. Fermented formulas, in which part of the formula is fermented by lactic acid bacteria that are then inactivated, contain postbiotic metabolites.
Every novel ingredient must pass two tests: safety, including toxicology, purity and the absence of harmful contaminants or residues from its manufacture, and suitability, meaning evidence that it supports normal growth and development and has the intended effect in infants. Regulators evaluate each case, often requiring clinical studies, and approval in one jurisdiction does not guarantee approval in another. Technologists must also check that the ingredient is stable through processing and storage and does not affect powder properties.
Follow-on formula, or follow-up formula, is intended as the liquid part of the diet of older infants, from about six months, once complementary foods have been introduced. Products for young children, often called growing-up milks or young child formulas, are marketed for children from about one to three years. Codex adopted a revised standard for follow-up formula in 2023 that covers follow-up formula for older infants, with composition close to infant formula, and drinks or products for young children, with requirements on protein, energy and added sugars.
The nutritional need for these products is debated. WHO's position is that follow-on formula is not necessary, and that growing-up milks are unnecessary for young children, who can obtain their nutrients from a varied diet with continued breastfeeding or, where appropriate, ordinary milk. Some growing-up milks contain added sugars and flavours and cost much more than milk. On the other hand, in some populations fortified milks can help meet needs for iron, vitamin D and other nutrients when diets are poor. Compositional rules aim to make the products nutritionally appropriate if they are used, for example by limiting added sugars and protein and requiring certain micronutrients.
The International Code of Marketing of Breast-milk Substitutes, adopted by the World Health Assembly in 1981, and the subsequent World Health Assembly resolutions set out principles to protect breastfeeding. They prohibit advertising and other promotion of breast-milk substitutes to the general public, free samples to mothers, promotion through health-care systems, gifts to health workers, and labels with pictures or text that idealise formula; labels must state the superiority of breastfeeding and give clear instructions and warnings. A 2016 World Health Assembly resolution and its accompanying guidance clarified that breast-milk substitutes include any milks specifically marketed for feeding infants and young children up to three years of age, including follow-up formula and growing-up milks, and called for an end to inappropriate promotion of foods for infants and young children.
The Code is not law in itself; governments implement it in national legislation to different degrees, from full legal implementation in many countries to partial or voluntary measures in others. Common national provisions include restrictions on advertising of infant formula and sometimes of follow-on formula, rules on cross-promotion where a growing-up milk's packaging resembles that of infant formula, controls on health and nutrition claims, and labelling requirements. Companies operating across markets must follow the strictest applicable rules, and many civil-society organisations monitor compliance.
For a dairy technologist in this sector, the marketing rules affect product design: label artwork, claims, age ranges, product naming and packaging similarity are all reviewed for compliance alongside composition.
Foods for special medical purposes are specially processed or formulated foods for the dietary management of patients with disease or particular medical conditions, used under medical supervision. Codex provides a standard for their labelling and claims (CXS 180-1991), and many jurisdictions regulate them separately from ordinary foods and from medicines. They include oral nutritional supplements, tube feeds, products for inborn errors of metabolism, formulas for preterm infants, human milk fortifiers and ketogenic formulas for epilepsy.
Enteral nutrition delivers nutrients through the gastrointestinal tract, by mouth or by tube. Products may be nutritionally complete or incomplete, standard or disease specific. Polymeric formulas contain intact proteins such as milk protein concentrate, caseinates and whey proteins; semi-elemental formulas contain peptides for patients with impaired digestion; elemental formulas contain free amino acids. Energy density ranges from about 1 kcal/mL for standard feeds to 2 kcal/mL or more for concentrated ones, and high-protein versions are used in illness, wounds and frailty. A patient receiving 500 mL of a 1.5 kcal/mL feed obtains 750 kcal.
Milk proteins dominate the field because of their quality, amino acid profile, functionality and availability. Their properties differ: whey proteins empty from the stomach quickly and are rich in leucine and cysteine; casein clots in the acid stomach and is digested slowly, which gives a sustained release of amino acids but can slow gastric emptying in tube-fed patients. Glycomacropeptide, purified from sweet whey, is naturally almost free of phenylalanine and is used in foods for people with phenylketonuria, alongside phenylalanine-free amino acid mixtures.
Medical nutrition products are often liquids sterilised by retort or by UHT treatment with aseptic filling, sold ready to use in bottles or pouches, so they must stay stable for many months at ambient temperature. High protein and high energy concentrations create technical problems. Protein must withstand sterilisation without coagulating; caseinates and micellar casein are heat stable, whereas whey proteins aggregate on heating, so high-whey liquid products need hydrolysed or specially processed whey, pH control and stabilising salts. Viscosity rises steeply with protein concentration, and tube feeds must flow through narrow tubes. UHT products can thicken and gel during storage, called age gelation, through protease action or physicochemical changes, and can show sedimentation, creaming and Maillard browning.
Formulators manage these with choice of protein ingredients, mineral balance and chelating salts such as citrates and phosphates, homogenisation, emulsifiers and stabilisers such as carrageenan, and processing conditions. Powders, which are reconstituted before use, avoid some stability problems but bring hygiene requirements at preparation.
Texture-modified products serve people with swallowing difficulties (dysphagia), whose drinks must be thickened to defined levels; the International Dysphagia Diet Standardisation Initiative describes levels from thin liquids to regular foods. Thickeners based on xanthan gum or modified starch, and pre-thickened milk drinks, must keep their consistency over time and in the mouth, where amylase can thin starch-based thickeners.
Milk proteins are the leading proteins in sports nutrition. Exercise followed by protein intake stimulates muscle protein synthesis, and the amino acid leucine is a key signal through the mTOR pathway. Whey protein is rapidly digested, gives a fast and high rise in blood amino acids and contains roughly 10 to 11% leucine, more than most proteins. Research summarised by sports nutrition bodies suggests that about 20 to 25 g of high-quality protein, or about 0.25 to 0.3 g per kg of body weight, per meal maximises muscle protein synthesis in young adults, and that daily intakes of about 1.4 to 2.0 g per kg suit most athletes in training. A 25 g serving of whey protein at 11% leucine supplies about 2.75 g of leucine. Casein, digested slowly, is used before sleep to provide amino acids overnight.
Ingredients include whey protein concentrates such as WPC 80 (about 80% protein), whey protein isolates (90% or more protein, low in lactose and fat), whey protein hydrolysates (faster absorption, but bitter), micellar casein and milk protein concentrates. To supply 20 g of protein from WPC 80 needs 25 g of powder. Chocolate milk and other milk drinks are used as recovery drinks because they supply protein, carbohydrate, fluid and electrolytes.
Formats include powders, ready-to-drink beverages and protein bars. Bars harden during storage because of moisture migration, protein aggregation and Maillard reactions; formulators use hydrolysed proteins, specific humectants and blends to delay hardening. Clear acidic whey drinks use heat-stable whey isolate at low pH. Sports products are also a target for adulteration, such as 'amino spiking' to inflate apparent protein content, so specific protein tests are used.
Ageing brings sarcopenia, the progressive loss of muscle mass, strength and function, which increases falls, frailty and dependence. Older muscle responds less to protein, a phenomenon called anabolic resistance, so older adults need more protein per meal to achieve the same response; expert groups have recommended intakes of about 1.0 to 1.2 g per kg per day for healthy older adults, and more during illness, compared with the general adult reference of 0.8 g per kg. Distributing protein across meals, with about 25 to 30 g or more of high-quality, leucine-rich protein per meal, is recommended. For a 70 kg person, 0.4 g per kg per meal is 28 g of protein.
Dairy products and proteins suit this need: they are rich in leucine, digestible, and also supply calcium, vitamin D when fortified, vitamin B12 and riboflavin, all relevant to bone and nerve health in ageing. Products include high-protein milks and yoghurts, protein-enriched desserts, oral nutritional supplements, and fortified powders to add to foods. Lactose intolerance is common in many older populations, so lactose-reduced versions are useful.
Design must account for reduced appetite, changes in taste and smell, chewing and swallowing difficulties and the need for small, energy- and protein-dense portions. High-protein products must still taste good and have pleasant texture, which brings the same technical problems of viscosity, heat stability and astringency as medical nutrition. Clinical evidence supports protein and exercise together for maintaining muscle, and nutrition products are most effective as part of such a combined approach.
A student uses this subject to see how dairy chemistry, microbiology and processing come together in the most regulated dairy product. They learn why cow milk must be modified for infants, how whey and fat blends are chosen, how a spray-dried formula is made and why the dry zone of a powder plant is managed so strictly. In examinations they answer questions on human milk composition, Codex ranges, Cronobacter and hydrolysates, and practise formulation and energy calculations. During in-plant training they see why each hygiene rule exists and how batch records give full traceability from ingredient lots to finished cans.
A formulation or quality technologist with five years in infant or medical nutrition designs and adjusts recipes to meet several countries' standards at once, calculates premixes and overages, validates dry-blend homogeneity, runs environmental monitoring in the dry zone and investigates Enterobacteriaceae findings, checks labels against marketing rules, and works with clinicians on tolerance studies. They also solve stability problems in high-protein liquids and powders. When a customer complaint or an environmental positive arrives, they lead the root-cause investigation, decide what product to hold, and document corrective actions for auditors and regulators.
A senior technical or regulatory director decides plant designs and hygiene zoning, approves new ingredients such as human milk oligosaccharides or structured lipids for each market, leads crisis management when a pathogen is found or a recall is needed, negotiates with regulators on registrations and standards, and ensures that marketing complies with the Code and national laws. They balance cost, supply security and scientific evidence across a global portfolio. They also plan capacity and supply of critical ingredients such as demineralised whey, structured lipids and oligosaccharides, so that a single supplier failure cannot stop production of a product on which infants depend.
A senior researcher studies human milk and translates findings into formula: characterising human milk components, testing novel ingredients in clinical trials, modelling the digestion of formula proteins and lipids, developing new hydrolysates with low allergenicity, and evaluating the long-term outcomes of formula-fed infants. They sit on expert committees that set standards and must keep a strict separation between scientific evidence and commercial interest. They also mentor clinical and technical teams, design studies that regulators will accept, and publish negative as well as positive results so that the evidence base stays honest.
This manual quotes Codex ranges and a few national rules as examples; it does not list every nutrient limit or every country's requirements, which must be read in the current legal texts. Human milk composition values are typical ranges, and published means differ. Evidence on partially hydrolysed formulas, some novel ingredients and the long-term effects of human milk oligosaccharides is still developing and is described as such. Clinical management of cow milk protein allergy, preterm nutrition and disease-specific enteral nutrition belongs to medicine and dietetics and is covered only from the product side. Protein intake recommendations for athletes and older adults are those of expert groups and vary between them.
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.
These notes are free to read here, with no account.
What the Laisha app adds:
Free for ten days, then a subscription. We would rather write that here than have you find it later.