Compositional and microbial quality of heat-treated milk brands marketed in Lusaka, Zambia

摘要

ThestudywasconductedtoassessthecompositionalandmicrobialqualityofpasteurizedandUltraHighTemperature(UHT)treatedmilkonthemarketinLusaka,Zambia.Atotalof18brandsofmilk(7pasteurizedand11UHTtreated)werepurchasedfromsupermarketsandthisformedthesamplesizeofthestudy.ThequalityofmilkwasevaluatedbyassessingitforTotalBacteriaCount(TBC),TotalColiformCount(TCC),isolationofStaphylococcusspp,SalmonellasppandClostridiumperfringesbyculturingthesamplesofmilkonstandardplatecountagar,violetredbileglucoseagarandselectivemedia.Milkcomponents,freezingpointandaddedwaterweredeterminedusingLactiCheckultrasonicmilkanalyserwhileantibioticresidueusingCopanMilkTestandBetaStarComboTestkit.nbsp;Thebutterfatcontentofheattreatedmilkrangedfrom2.91#8211;3.74%,proteinfrom2.05-3.47%andlactose2.94-5.07%.SolidNotFat(SNF)contentrangedfrom7.28-9.23%,with5samplesrecordingbelowtherecommendedstandardof8.3%.Freezingpointrangedfrom-0.4500Cto-0.6070C.About16.6%ofthemilksamplescontainedantibioticresidue.Totalbacterialcountofpasteurizedmilkrangedfrom6,000#8211;38,000cfu/ml.TherewasnobacterialgrowthinUHTtreatedmilksamplesandthuswithintheacceptablestandard.Thecoliformcountin4ofthe7pasteurizedmilksamplesrangedfrom68-188cfu/mlwhichishigherthanacceptablestandardof5cfu/ml,whileUHTtreatedmilkdidnotcontainanycoliform.Threebrandsofmilk(16.6%)werefoundwithaddedwatercontaining10.6,13.6and33%respectively.Unacceptablepresenceofcoliform,antibioticresidueandaddedwaterinheattreatedmilksampleisindicativeofhealthhazardstoconsumersandlackofmonitoringbyregulatoryauthority.Thereisneedtotestandmonitorprocessedmilkavailabletoconsumersperiodically,educatingfarmersontheneedofstrictobservanceofantibioticwithdrawalperiodandimposingstifferpenaltyonmilkadulteration.