Dairy plant equipment and cleaning in place

In short

Dairy plant equipment is the chain of sanitary machinery through which milk moves — pumps, pipelines and fittings, plate and tubular heat exchangers, cream separators, homogenisers, storage and silo tanks, valves and clusters — all built so that milk never meets a dead end, a rough weld or a corner that cannot be cleaned. Cleaning in place (CIP) is the automated circulation of water, hot caustic and acid solutions through that assembled equipment at controlled time, temperature, concentration and flow, without dismantling it. Together they decide whether a pasteurised milk pouch keeps for 48 hours or sours in 12, because almost every keeping-quality failure in an Indian dairy traces to inadequate cleaning rather than inadequate heating. The topic is examined in Dairy Engineering and Dairy Plant Management papers, in ICAR/ASRB and GATE-equivalent dairy papers, and is the single most asked practical area in interviews at Amul/GCMMF member unions, Mother Dairy, Nandini (KMF), Aavin, Hatsun, Heritage, Dodla, Schreiber Dynamix and the equipment makers (GEA, Tetra Pak, SPX/APV, Alfa Laval, IDMC, Goma).

Explained

Sanitary design: the rules behind every dairy machine

• 3-A / sanitary standards principle: all product-contact surfaces must be smooth, non-porous, non-absorbent, non-toxic, corrosion-resistant, self-draining and accessible for cleaning or inspection.
• Material: AISI 304 stainless steel is the dairy workhorse; AISI 316 / 316L (with 2-3% molybdenum) is used where chloride or acid attack is likely — brine chillers, acid lines, whey and paneer plants. Surface finish typically 2B or polished to Ra ≤ 0.8 µm.
• Why not copper or mild steel: copper and iron catalyse fat oxidation (oxidised/metallic flavour) and corrode; brass and galvanised surfaces are prohibited in product contact.
• Gaskets and elastomers: nitrile (NBR) for general milk duty, EPDM for hot caustic and steam/CIP, silicone and PTFE for high temperature and fat; all must be food-grade and replaced on schedule — a nicked gasket is a classic biofilm site.
• Welds: butt-welded, argon-purged, ground and polished internally; crevices, lap joints and pockets are design faults, not maintenance faults.
• Slope and drainability: horizontal lines are laid with a fall of about 1 in 100 (1%) toward a drain point; no "U" loops, no dead legs longer than about 2-3 pipe diameters (the rule of thumb is ≤ 2D from the flowing stream, some codes allow 3D).
• Fittings: SMS (Swedish) and DIN unions, IDF/ISO and Tri-Clover (clamp) ferrules; clamp fittings are preferred for frequently opened points. Threaded pipe is not used in product lines.
• Indian codes: FSSAI Food Safety and Standards (Licensing and Registration) Regulations, 2011 — Schedule 4 Part II/III lays down hygienic premises and equipment requirements for a dairy; FSS (Food Products Standards and Food Additives) Regulations for product standards; BIS publishes equipment and hygiene standards for milk processing (IS 4446 covers milk pasteurising plant; several older dairy-equipment IS numbers have been revised or withdrawn — confirm the current number and edition before quoting). The Milk and Milk Product Order (MMPO) licensing regime was subsumed into the FSS Act, 2006 framework.

Fluid handling: pumps, pipes, valves and tanks

• Centrifugal pump: impeller in a sanitary casing; low cost, high flow, used for water, milk at low viscosity, CIP circulation. Not self-priming; flow varies with head; high shear risk if throttled and recirculated — can damage the fat globule and cause lipolysis/"churning".
• Positive displacement pumps: lobe/rotary and twin-screw pumps for cream, curd, dahi, condensed milk, ice-cream mix; gentle, self-priming, flow nearly independent of head. Peristaltic/hose pumps for culture and delicate products.
• Pump rules: always flooded suction, minimum bends, pump near the tank bottom; NPSH available must exceed NPSH required or the pump cavitates (noisy, pitted impeller, falling flow).
• Pipelines: 25, 38, 51, 63.5, 76 mm (1", 1½", 2", 2½", 3") sanitary tube; design milk velocity ≈ 1-2 m/s (above ~2.5 m/s pressure drop and fat damage rise; below ~0.5 m/s solids settle). CIP return velocity ≥ 1.5 m/s for turbulent scouring.
• Valves: butterfly valves (manual/pneumatic) for on-off; seat/shut-off valves, flow diversion valves (FDV) in pasteurisers, mix-proof double-seat valves for CIP-while-producing in automated plants; constant-pressure (back-pressure) valves downstream of homogenisers.
• Tanks and silos: insulated double/triple-walled stainless silos (10,000-200,000 L), with slow-speed agitator (to prevent creaming without churning), level sensor, CIP spray ball, thermometer, manhole, outlet at the lowest point. Balance/float tank feeds the pasteuriser at constant head.
• Air and vacuum: compressed air touching milk (air-eliminators, pouch fillers) must be oil-free and filtered; vacuum lines are a contamination route if not cleaned.

Heat exchangers and process equipment

• Plate heat exchanger (PHE): corrugated SS plates in a frame with gaskets, forming alternate channels for milk and medium; counter-current, very high overall heat transfer coefficient, compact, and allows regeneration — incoming raw milk is pre-heated by outgoing hot milk. Regeneration efficiency commonly 85-93%, which is where a pasteuriser's steam and chilling economy comes from. Limits: gasket life, cannot handle high viscosity or particles, pressure limited, needs the milk side at higher pressure than the medium side so a plate pinhole cannot leak coolant/water into milk.
• Tubular heat exchanger: concentric tube or shell-and-tube, no gaskets in product contact, takes higher pressure and viscous/particulate products, longer run time — standard for indirect UHT and for condensed products; bulkier and lower regeneration.
• Scraped-surface heat exchanger: for ghee, ice-cream, cheese sauce, highly viscous or fouling products.
• Cream separator: self-desludging disc-bowl centrifuge; milk enters the bowl, the denser skim moves to the periphery and fat (lighter) moves inward along the disc stack; separation follows Stokes' law, enhanced by centrifugal acceleration, so efficiency rises with bowl speed, disc number and falls with throughput. Warm separation (40-45 °C) is normal; cold-milk separators exist at lower capacity. Fat in skim milk should be ≤ 0.05% (good practice ≤ 0.03-0.05%).
• Clarifier and bactofuge: a clarifier centrifuge removes leucocytes, dirt and somatic debris; a bactofuge centrifugally removes bacteria and spores (useful against *Bacillus* spores in cheese milk). Modern plants often use the clarifixator/ hermetic separator with integrated clarification.
• Homogeniser: a high-pressure positive-displacement piston pump (3 or 5 plunger) plus one or two spring/hydraulically loaded homogenising valves. Fat globules are reduced to < 2 µm by combined shear, turbulence and cavitation at the valve gap. Two-stage: first stage ~150-200 bar does the size reduction, second stage ~30-50 bar breaks up clusters. Done at 60-70 °C (fat must be liquid; cold homogenisation is ineffective and raises lipolysis). Must never be run dry; needs a safety/pressure relief valve and clean plunger-seal water.
• Other units: hot-water/steam injection and PHVac deaerators, milk powder evaporators and spray dryers, butter churn/continuous butter-making machine, cheese vat, paneer press, pouch filling machines (form-fill-seal), CIP skid, and refrigeration (ammonia/freon chilled water or ice-bank tank at ~0.5-1 °C giving 4 °C milk).

Cleaning: soil, chemistry and the detergent choice

• Why cleaning is a process, not a chore: milk residue dries into a film of protein, fat, lactose and minerals; microbes colonise it and form a biofilm — an extracellular polymer matrix that resists sanitizer at 10-1,000 times the free-cell dose. Once a biofilm matures, only mechanical/chemical removal of the soil removes the organisms.
• Types of soil: (i) fat — removed by hot alkali and surfactants; (ii) protein — alkali, with chlorinated alkali or enzymes; (iii) lactose/sugars — water-soluble, removed by warm water rinse; (iv) mineral deposit / milk stone — calcium and magnesium phosphates baked onto hot surfaces, removed only by acid; (v) burn-on — heavily denatured protein-mineral deposit on pasteuriser and UHT heating sections.
• Alkali (caustic) wash: NaOH 0.5-2.0% (commonly 1-1.5% for a pasteuriser, 0.5-1% for cold lines) at 70-80 °C; saponifies fat, peptises and dissolves protein. Additives: sequestrants (EDTA, gluconate, polyphosphate) to stop hardness precipitating, wetting agents, antifoam.
• Acid wash: nitric acid 0.5-1.0% (sometimes phosphoric or sulphamic) at 60-70 °C; dissolves milk stone, passivates stainless steel, neutralises alkali carry-over. Hydrochloric acid is never used — chlorides pit stainless steel.
• Sanitizers: sodium hypochlorite 100-200 ppm available chlorine (cold, short contact, then rinse — corrosive if hot or prolonged), peracetic acid (PAA) 0.1-0.2% (no rinse needed at use strength, effective cold, good on biofilm), quaternary ammonium compounds (not for membrane plants; foaming), iodophor (acidic, visual colour), and hot water/steam 85-90 °C for 15-20 minutes as a chemical-free sanitation.
• Water quality matters: potable water conforming to IS 10500 (drinking water specification); hard water wastes caustic and leaves scale, so softened or RO water is used for final rinse and sanitizer make-up.
• Compatibility: chlorine + acid together releases toxic chlorine gas; never mix. Caustic attacks aluminium and tin; PAA degrades with heat and metal catalysis.

CIP: systems, circuits and the standard cycle

• Definition: CIP is cleaning the interior surfaces of assembled plant — pipes, tanks, heat exchangers, pumps, valves — by circulating cleaning solutions at defined time, action (flow/turbulence), concentration and temperature (TACT), with no dismantling and minimal manual work. Parts that cannot be CIP'd (filler nozzles, some valve seats, homogeniser valves) get COP (cleaning out of place) in a soak tank or manual cleaning.
• Single-use (lost) CIP: solutions are used once and drained — small plants, sticky soils, high-risk lines; simple, low capital, high chemical and water use.
• Re-use CIP: caustic and acid are recovered to dedicated tanks, strength is topped up by conductivity-controlled dosing, and re-used for many cycles — low chemical and effluent cost, needs tanks, filters and controls. Most medium and large Indian dairies run re-use CIP.
• Centralised vs decentralised (satellite) CIP: a central kitchen serves the whole plant through long lines (cheaper plant-wide, more liquid in transit); satellite skids sit near the equipment (faster, less loss of heat and solution, independent circuits). Large dairies use a central chemical store with satellite skids.
• CIP skid parts: fresh-water tank, hot-water tank, caustic tank, acid tank, recovery/rinse tank, plate heater or steam injector, supply pump, return pump, filter/strainer, conductivity cell, flowmeter, temperature and level sensors, PLC with recipes and printout.
• Standard 5-step (or 6-step) cycle for a milk line / pasteuriser:
  1. Pre-rinse with warm water (about 40-45 °C) for 5-10 min, to drain — removes 90-95% of residual milk solids; hot water here would cook protein onto the surface, cold water would set fat.
  2. Alkali circulation: 1-1.5% NaOH at 75-80 °C for 20-30 min, returning to the caustic tank.
  3. Intermediate rinse with water, 5-10 min, until return is neutral.
  4. Acid circulation: 0.5-1% HNO₃ at 60-70 °C for 10-20 min (daily or alternate-day in cold lines, every cycle on heat sections).
  5. Final rinse with potable/softened water till neutral and clear.
  6. Sanitation immediately before the next production run — hot water 85 °C/15 min or chemical sanitizer; sanitizing long before use lets recontamination occur.
• Spray devices for tanks: static spray balls (low pressure, 1.5-2.5 bar, sized at roughly 30 L/min per metre of tank circumference — simple, needs good coverage design) and rotary jet heads / rotating spray heads (higher pressure 4-8 bar, strong impingement, far less water and chemical, used in silos and big tanks).
• Flow requirement: in a pipeline the solution must be turbulent — design on velocity ≥ 1.5 m/s (commonly 1.5-2.1 m/s), i.e. Reynolds number well above 4,000; in a PHE the CIP flow is usually taken as about 1.2-1.5 times the product flow.
• Verification and monitoring: conductivity for caustic/acid strength and phase change, titration for exact concentration, temperature and flow logs, visual and odour check of the return, final rinse-water pH/conductivity, swab and rinse-water microbiology, and ATP bioluminescence swabs (results in RLU within a minute) as a rapid hygiene check. Records are kept for FSSAI audits and HACCP verification.
• Interlocks: CIP and product must be positively separated — swing-bend panels, double-seat mix-proof valves, or physically disconnected lines — to prevent caustic entering milk. Caustic in milk is a serious recall-level incident; the FSSAI/HACCP control is a routine alkalinity check on the first product after CIP.

Plant utilities, hygiene management and effluent

• Utilities: steam (boiler, usually 10.5 kg/cm² generation, reduced for process; culinary steam filtered for direct contact), chilled water/ice-bank, compressed air, refrigeration (ammonia in large plants), and hot water generation using condensate and regeneration heat.
• Hygiene programme: personal hygiene and medical fitness of food handlers, GMP/GHP, pest control, potable water testing, equipment swabs, air plate counts in filling rooms, and HACCP/FSSAI Schedule 4 compliance — often certified to FSSC 22000 / ISO 22000.
• Validation of a CIP: the recipe is validated once (soil challenge, swabs, borescope) and then monitored every cycle. A changed pump, a longer line or a new product means revalidation.
• Water and effluent: a well-run dairy uses about 1-3 litres of water per litre of milk processed (older plants far more). Dairy effluent is high in BOD (about 1,000-3,000 mg/L raw) because of milk solids, and alkaline/acidic in surges from CIP; treatment is equalisation + neutralisation, oil/fat trap, aerobic (ASP/MBBR/SBR) or UASB, with discharge limits set by CPCB/State Pollution Control Boards under the Water (Prevention and Control of Pollution) Act, 1974 (typical inland surface discharge limits: BOD 30 mg/L, pH 5.5-9.0 — check the current consent conditions, which vary by state and stream).
• Energy and loss reduction: regeneration in the pasteuriser, condensate recovery, VFDs on pumps, pigging and air-blow of lines to recover product, optimising CIP frequency — milk loss of even 0.5% of throughput is a direct profit loss.

Key points

• Sanitary design - smooth, crevice-free, self-draining, accessible 304/316 stainless contact surfaces; no threads, lap joints or long dead legs.
• Dead leg rule - an unflushed branch longer than about 2 pipe diameters harbours soil and bacteria; design them out.
• Regeneration - raw milk is heated by outgoing pasteurised milk in a PHE; 85-93% regeneration cuts steam and chilling load proportionally.
• Pressure rule in a PHE - pasteurised milk side must be at higher pressure than raw/medium side so a leak cannot contaminate it.
• Homogenisation - two-stage at 150-200 bar then 30-50 bar, at 60-70 °C, reduces fat globules below 2 µm and prevents creaming.
• Separator - disc-bowl centrifuge; separation efficiency rises with bowl speed and disc count, falls with throughput; fat in skim ≤ 0.05%.
• PD pumps for viscous/shear-sensitive products, centrifugal for water, milk and CIP circulation.
• Milk velocity 1-2 m/s in product lines; CIP velocity ≥ 1.5 m/s for turbulent scouring.
• TACT - Time, Action (mechanical), Concentration, Temperature; weaken one and another must be strengthened.
• Soil types - fat and protein need hot alkali; mineral milk stone needs acid; lactose dissolves in warm water.
• Caustic step - 1-1.5% NaOH at 75-80 °C, 20-30 min; acid step - 0.5-1% HNO₃ at 60-70 °C, 10-20 min.
• Never HCl, never chlorine + acid - chlorides pit stainless steel; the mixture evolves chlorine gas.
• Pre-rinse warm, not hot - hot water denatures protein onto the surface and makes cleaning harder.
• Sanitize just before use, not after cleaning and then idle overnight.
• Biofilm - a protected microbial film in a crevice or worn gasket; routine sanitizer alone will not remove it.
• Re-use CIP saves chemicals and effluent load; single-use CIP suits small or high-risk circuits.
• Verification - conductivity and titration for strength, temperature/flow logs, swabs, rinse-water counts, ATP bioluminescence.
• Compliance - FSSAI Schedule 4 hygiene requirements, HACCP/ISO 22000-FSSC 22000, IS 10500 water, CPCB/SPCB effluent consent.

Formulas and examples

Example 1 — CIP flow and velocity in a 51 mm line. A 2" (51 mm OD, 48.6 mm ID) sanitary line must be cleaned at 1.8 m/s.

• A = (π/4) × (0.0486)² = 0.7854 × 0.002362 = 1.855 × 10⁻³ m².
• Q = 1.855 × 10⁻³ × 1.8 = 3.339 × 10⁻³ m³/s = 3.339 × 3,600,000 /1000 = 12,020 L/h ≈ 12 m³/h.
• Check turbulence for the caustic solution (ρ ≈ 1,015 kg/m³, µ ≈ 0.0004 Pa·s at 78 °C): Re = 1,015 × 1.8 × 0.0486 / 0.0004 = 88.79/0.0004 ≈ 2.2 × 10⁵ — strongly turbulent, so the CIP pump must deliver at least 12 m³/h at the circuit head.

Example 2 — Regeneration saving in a 10,000 L/h pasteuriser. Raw milk at 4 °C is regeneratively heated to 68 °C, final pasteurisation 72 °C.

• Regeneration efficiency = (68 − 4)/(72 − 4) × 100 = 64/68 × 100 = 94.1%.
• Mass flow ṁ = 10,000 L/h × 1.03 kg/L = 10,300 kg/h = 2.861 kg/s.
• Heat still needed in the heating section: q = 2.861 × 3.93 × (72 − 68) = 2.861 × 3.93 × 4 = 44.97 kW.
• Without regeneration: q = 2.861 × 3.93 × (72 − 4) = 2.861 × 3.93 × 68 = 764.6 kW — regeneration saves about 720 kW of heating and a similar order of chilling duty.

Example 3 — Preparing a CIP caustic tank. A 2,000 L CIP tank is to hold 1.5% w/v NaOH, using 98% pure flakes.

• NaOH required = 2,000 × 1.5/100 = 30 kg of pure NaOH → 30/0.98 = 30.6 kg of flakes.
• If 48% liquid lye of density 1.5 kg/L is used instead: NaOH per litre = 0.48 × 1.5 = 0.72 kg → volume = 30/0.72 = 41.7 L of lye.
• At the end of the wash, titration shows 1.1%. Top-up = (1.5 − 1.1)/100 × 2,000 = 8 kg pure NaOH = 8.16 kg flakes (or 11.1 L of lye).

Example 4 — Hypochlorite sanitizer dilution. 500 L of 150 ppm available-chlorine rinse is needed from 5% sodium hypochlorite.

• Chlorine required = 150 mg/L × 500 L = 75,000 mg = 75 g.
• 5% solution contains 50 g available chlorine per litre → volume = 75/50 = 1.5 L of hypochlorite in 500 L.
• Apply cold (≤ 25 °C) for 10-15 minutes; do not apply after an acid wash without an intermediate water rinse.

Example 5 — Separator fat balance. 1,000 kg of milk at 6.0% fat is separated into 40% cream and skim milk at 0.05% fat.

• Cream = 1,000 × (6.0 − 0.05)/(40 − 0.05) = 1,000 × 5.95/39.95 = 148.9 kg.
• Skim = 1,000 − 148.9 = 851.1 kg.
• Check: 148.9 × 0.40 + 851.1 × 0.0005 = 59.56 + 0.43 = 59.99 ≈ 60.0 kg fat = 6.0% of 1,000 kg. ✔
• If the separator drifts and skim fat rises to 0.10%, fat lost in skim = 851.1 × 0.001 ≈ 0.85 kg per 1,000 kg milk — in a 100,000 L/day plant that is roughly 85 kg of fat a day lost.

Where it is used

• Liquid milk dairies (Mother Dairy Delhi, Amul member unions, Nandini/KMF, Aavin, Heritage, Dodla, Hatsun): HTST pasteurisers, silos, pouch fillers, with automated re-use CIP between every shift.
• Product plants: cheese and paneer lines, ghee and butter plants, milk powder spray-drying units, curd/dahi and lassi lines, ice-cream plants — each with its own CIP recipe because soil type differs.
• Job roles: Shift/Plant Engineer, Production Officer, Quality Assurance Officer, Maintenance Engineer, CIP and Utilities Engineer, and sales/commissioning engineers with equipment makers (Tetra Pak, GEA, SPX Flow, Alfa Laval, IDMC Anand, Goma, Reliable Engineering).
• Government and cooperative sector: NDDB and state federation dairy plants under the National Dairy Plan; dairy engineering teaching and ICAR/NDRI research facilities.
• Audit and regulatory work: FSSAI inspections and FSSC 22000/ISO 22000 audits examine CIP records, chemical strength logs and swab results before anything else.
• Allied industries: beverages, breweries, pharmaceutical and nutraceutical plants use the same sanitary design and CIP logic (with WFI and SIP in pharma).

Interview questions

• Q: Why is the pre-rinse done with warm and not hot water? A: Water above about 55-60 °C denatures milk protein and bakes it onto the surface, while cold water sets the fat; 40-45 °C flushes both away.
• Q: What does TACT stand for in CIP? A: Time, Action (mechanical turbulence or impingement), Concentration and Temperature — the four variables; reducing one must be compensated by raising another.
• Q: Why is nitric acid used and hydrochloric acid never used? A: Nitric acid dissolves calcium-phosphate milk stone and passivates the stainless surface; hydrochloric acid supplies chloride ions that cause pitting and stress-corrosion cracking of stainless steel.
• Q: What is a dead leg and why does it matter? A: An unflushed branch or blind end longer than about two pipe diameters where CIP solution does not scour; milk residue stays, bacteria multiply and recontaminate every batch.
• Q: Why must the pasteurised milk side of a PHE be at higher pressure than the raw side? A: So that if a plate develops a pinhole, pasteurised milk leaks toward the raw/service side rather than raw milk or cooling water entering pasteurised milk.
• Q: How is homogenisation pressure split between the two stages and why? A: About 150-200 bar in the first stage to break fat globules, and 30-50 bar in the second stage to disperse the clusters that form immediately after the first stage.
• Q: What is a biofilm and how do you deal with it? A: A polysaccharide-encased microbial community anchored in a crevice or worn gasket; it resists sanitizers, so you must physically remove the soil — strip and manually clean the point, replace gaskets, then correct the design or CIP parameter that allowed it.
• Q: How do you verify a CIP cycle was effective? A: Chemical strength by conductivity and titration, temperature and flow records, visual inspection and borescope, final rinse-water pH/conductivity, swab and rinse-water microbiology, and ATP bioluminescence for a rapid result.
• Q: Which pump would you choose for cream or dahi, and why? A: A positive-displacement lobe pump — it is gentle, self-priming and gives near-constant flow against varying head, whereas a centrifugal pump would shear the fat and lose flow with viscosity.
• Q: Why is 316 stainless used in some places instead of 304? A: The molybdenum in 316 resists chloride and acid attack, so it is specified for brine, whey, acid lines and salted products.
• Q: What is the risk of mixing a chlorine sanitizer with an acid wash? A: It releases toxic chlorine gas and destroys the sanitizer — the two must always be separated by a thorough water rinse.
• Q: First product after CIP tastes soapy — what happened and what do you do? A: Caustic carry-over from an incomplete final rinse or a leaking mix-proof/diversion valve; stop and isolate the batch, check alkalinity and pH of the line, re-rinse to neutral, and investigate valve seat integrity before resuming.
• Q: Why is the separator run at 40-45 °C? A: Warm milk has lower viscosity and a larger density difference, so by Stokes' law in a centrifugal field the fat separates faster and the skim fat falls below 0.05%.

Common mistakes

• Treating CIP as "circulating hot caustic" and skipping the acid step — milk stone builds up on the heating section, insulating it and sheltering thermoduric bacteria.
• Fixing a dirty plant by raising sanitizer dose instead of removing the soil; a sanitizer applied over soil barely works.
• Sanitizing at the end of cleaning the night before, then leaving the line idle — recontamination happens; sanitize immediately before production.
• Confusing cleaning with sterilisation, or CIP with SIP (steam in place) — a clean surface is not a sterile one.
• Quoting CIP flow in L/h without checking velocity and Reynolds number, or sizing the CIP pump on the product pump's duty.
• Arithmetic slips in fat balance and heat-duty sums — forgetting to convert L/h to kg/h using milk density (≈ 1.03 kg/L), or using cp of water instead of milk (3.93 kJ/kg·K).
• Homogenising cold milk or running a homogeniser dry; and assuming homogenisation kills bacteria — it does not, it only subdivides fat.
• Ignoring water hardness: caustic made in hard water precipitates scale and wastes chemical.

Related topics

Market milk processing: pasteurisation and UHT · Milk composition and properties · Milk procurement and quality testing · Dairy microbiology and spoilage · Refrigeration and cold chain in dairy · Food safety management: HACCP, FSSAI and ISO 22000