Module contents - theoryIntroduction Dairy processing Dairy products manufacturingDairy factory & the environmentQuality assurance of dairy products Marketing of fresh milk and milk products

4. Dairy factory & the environmentEstablishment of a dairy factoryUnderstanding the utilities & servicesMaintenance of a safe environmentDisposal of liquid and solid waste

Dairy factory & the environmentWhy study on Dairy factory & the environment?Quality assurance of productsCustomer satisfactionSustainable businessHealth & hygieneStaff & consumersEnvironmental protection

1. Establishment of a dairy factorySite selection criteriaFollowing aspects should be considered when selecting a siteWater supply and qualityMilk catchments supply areaLand availability, drainage and qualityProximity of other buildings and activitiesProximity to a roadEffluent disposalGood drainageAvoiding environmental pollutants & contaminants

Cont; Establishment of a dairy factoryDesign & constructions- type of buildingStructural soundnessBuilding for raw materialsBuilding for processingBuilding for product store Building for officeBuilding for other

Cont; Establishment of a dairy factoryConstruction materialsFoundation, floor, walls, roofing etcAvoid deterioration, cleaning problem, infection, safety hazards etcFloor non slip, resistant to materials, easy clean, free draining etcWater supply & accessoriesEffluent piping & drainageLight and power supplyCeilingDoors & windowsVentilation and air circulation systemsFollow the dairy processing standards Maximum for 0.5 m partcals/m3 respective areas such as aseptic filling, culture rooms, processing area, storesUse food grade materials & equipments where applicable

Floors & Ceiling

Cont; Principles for the establishmentArrangements & installations of equipmentArrangement of equipmentNeed to consider segregation of processPrevent cross-contaminationConsider hygiene and safety of operationFlow of raw material through to product Process sequenceAccess to each item & equipment Operation, cleaning, storage etcStorage & dispatch of productsDisposal of by-products

Cont; Principles for the establishmentInstallationSome equipment must be securely fixedSome should be at a convenient height for workingPortables can be located as desiredWater supply should be installed on opposite wallsElectric wiring and installationShould be carried out by qualified personnelShould be installed appropriately

Layout of a small dairy plant

Establishment of collection & reception unitMilk run in a closed system from cow to cooling tank39 C4 C4 C

Cont; Establishment of collection & reception unitAn insulating cover protects the milk from heat and coldSmall scale collection unit

Cont; Establishment of collection & reception unitMeasuring milk intake in a tanker reception hallLarge scale collection unit

Cont; Collection & reception of milkLarge scale collection unit

Establishment of a cooling & chilling unitBulk cooling tank with agitator & chilling unit

Establishment of a process control systemVideo Display Unit

Establishment of a quality control unitTesting for raw materialsTesting for products

Processing & manufacturing equipments

Suitable processing equipments

Hygienic handling

2. Utilities & services Supply of waterPotable waterHot water Cool water SteamRefrigerationChilling - variableDeep freezing Compressed air Electricity

Dairy water supplySpecifications for water Water is used for all cleaning purposes in a milk processing plant So, satisfactory bacteriological & chemical quality is required

Water supplyNatural water bodyPipe well with submersible pumpWater should be processed

Water pressure tank1 Tank2 Drain valve3 Safety valve. Opens at 600 kPa4 Pressure switch5 Check valve6 Liquid-ring pump7 Vent valve8 Pressure gauge9 Level glass

Heat productionWater Steam/hot waterHeatingEnthalpy ?Enthalpy ?

Phase change of water What is enthalpyEnergy or heat content of water Reference point for enthalpy of water and steam is 0 C Enthalpy increases by 4.18 kJ/kg until boiling point At the boiling point;Large input of enthalpy causes No temperature change but a phase changeLatent heat is added and steam is producedOnce all the water has vaporized;Temperature again increases with the addition of heatSensible heat of the vapor

Thermodynamics of steam

Steam & Hot water productionDairy requires large quantities of thermal energyHeat various productsHeat detergent solutionsSteam at 140 150C used as a heating mediumSteam productionProduce in large tubeTubes surrounded by the flameChest heat exchangers Direct hit flame

Steam production & distribution Pressure inside boiler is high, 300-800 kPa Pressure create high steam temperatureSaturated steam distributed to heat exchangerIt provides heat by condensing back to waterGiving up its latent heat Desired temperature gain by pressure reducing valve Condensate hot water return to the boiler & reuse

Steam production & distribution systemBoilerDistribution vessel for high-pressure steamPressure reducing valveDistribution vessel for low-pressure steamPoints of consumptionSteam trapsCondensate tankCondensate pumpFeed-water tankWater softening filterFeed-water degassingFeed-water pump

Steam Production & utilization

Steam Production

Steam boilers

System for steam distribution and condensate collection

RefrigerationRefrigerators have four basic elementsEvaporatorA compressorA condenserA refrigerant flow controller Refrigerant circulates through above elementsCFC, NH3 Change from liquid to gas back to liquid

Refrigeration cycleEvaporatorLiquid refrigerant evaporates in low pressureAbsorbs latent heat of vaporization Cools the surroundings Evaporator is at the lowest temperature in the system So, heat flows to it CompressorRefrigerant vapor is sucked into a compressorCompressor pump increases the pressure Then exhausts it at a higher pressure to the condenser

Cont; Refrigeration cycleCondenserCondense refrigerant back to liquid Release latent heat to cooling medium Water Air Refrigerant flow controllerRefrigerant passes to flow controllerIt expanse the refrigerant Then release to lower pressure evaporator

Refrigeration cycle-refrigerator

Schematic representation of a refrigeration system

Compressed-air installation

3. Maintenance of a safe environmentPlant/buildings hygieneMachinery hygieneRaw materials hygieneWorkers hygieneStorage hygiene

Cont; Maintenance of a safe environmentPlant hygienePeople -Do & dontPeople doProtective clean clothingCleaning system handsBefore & after processing activitiesClean hands thoroughly immediately after lavatoryReport any diseasesCover any cuts or woundsPeople dontSmokingEating OthersAspects cleaning

Cont; Maintenance of a safe environmentAspects cleaning means;Cleaning, sanitising & sterilising of dairy & its equipmentMilk manufacturers obliged to maintain high hygienic standardsThis applies to equipments & the staffObligation can be considered under three headingsTrade obligationGood for tradeMoral obligationCustomers trustLegal obligationLaw attempts to protect the customer

Cont; Maintenance of a safe environmentCleanliness of equipment can be classified at four levelsPhysical cleanliness (pre-rinse) Remove all visible dirt from the surfacesChemical cleanlinessRemove all microscopic residuesSanitationAttained by disinfectionInactivate or remove micro-organisms on surfacesSterilizationDestroy all micro-organisms on the equipment

Chemical effects and soil characteristicsDeposits on a heated surface

Cont; Maintenance of a safe environmentCleaning & sanitizing should prevent;Accumulation of undesirable micro-organisms In the equipment & surroundingsDevelopment of bad smells in the equipment Which pass on to the productLoss of efficiency in a dirty separatorPossible corrosion of metal parts due to lactic acidMould growth on surfacesOn equipments & surroundingsContamination of the product with pathogens

Cleaning procedurePre wash the equipment with clean cold waterRemove as much of the dairy productsDo immediately after the product removedWash the equipment with warm water (50C)Remove fatty materialWash the equipment with a detergent solutionFollowing the manufacturers instructionsDrain the detergent solutionRinse at least three times with clean cold water Ensure removal of all traces of the detergentSanitize the equipmentChoose suitable sanitizer with manufacturers instructions Rinse the equipment with clean water Remove all residues of the sanitizing agentSterilize the equipmentUse suitable chemical sterilizerScald with 80C water when no sterilizeLastly, store equipments in a clean, dry, dust-free area

Cleaning and biological agentsWaterSolvent transport medium and biocide (when heated)Soft water for cleaningTotal hardness: < 50ppm (as CaCO3)Chloride:

Cont; Cleaning and biological agents2. Detergents Has combine the actionsSuch as wetting, dissolving, dispersing, buffering, rinsing etcProperties of detergentsWetting and penetrating powerEmulsifying powerSaponifying powerDefloculating powerCompletely and quickly soluble in waterNon corrosive

Cont; Cleaning and biological agentsDairy detergents are broadly classified into four groups Multipurpose Alkali detergentsNaOHSodium metasilicateTrisodium phosphateSodium polyphosphatesSodium carbonateAcid detergentsNitric acidPhosphoric acid Sulphamic acidTartaric Citric acids EnzymesProteasesBiocides/sanitizersHeat, chlorine, hypochorites, iodophors, H2O2, formaldehydeUltra-violet, radiation, electron beam

4. Disposal of liquid and solid waste

Various stages of a sewage treatment plant

Cont; Disposal of liquid and solid waste

Cont; Disposal of liquid and solid waste

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