Determining of adulteration of store bought milk by adding powdered milk, using the modified spectrophotometry

Abstract

Razvoj metoda u svrhu sprječavanja pojavljivanja na tržištu proizvoda koji ne udovoljavaju zakonskim propisima, jedna je od ključnih zadaća u području zaštite društva. Stoga postoji stalna potreba za razvojem brzih i pouzdanih metoda u kontroli ispravnosti prehrambenih proizvoda. Često se u mljekarskoj industriji zbog isteka roka trajanja mlijeko u prahu rekonstituira i dodaje u pasterizirano ili sterilizirano mlijeko te se bez oznake na deklaraciji proizvoda stavlja na tržište, dovodeći potrošače u zabludu. Potrošači imaju pravo znati što se nalazi u hrani, a proizvođači su ih dužni informirati i ne dovoditi ih u zabludu vezano uz sastav proizvoda, odnosno karakteristike hrane, posebno njezine prirode, identiteta i podrijetla, svojstava, količine, trajnosti kao i postupaka proizvodnje. Cilj rada bio je provjeriti ispravnost označavanja konzumnog mlijeka te utvrditi eventualno patvorenje dodatkom mlijeka u prahu. Uzorci mlijeka u svrhu izrade ovog rada nabavljeni su iz maloprodajne trgovačke mreže. Utvrđivanje eventualnog patvorenja mlijeka dodatkom mlijeka u prahu, provedeno je modificiranom spektrofotometrijskom metodom, a ispravnost njegovog označavanja provjerena je standardnim fizikalno-kemijskim metodama u Referentnom laboratoriju za mlijeko i mliječne proizvode, Zavoda za mljekarstvo, Agronomskog fakulteta Sveučilišta u Zagrebu. Na temelju analiziranih 15 uzoraka mlijeka samo 4 uzorka odgovarala su propisanoj zakonskoj regulativi i vrijednostima navedenim na deklaraciji proizvoda. Nadalje, analizom točke ledišta kao kontrolom patvorenja mlijeka s dodatkom vode, utvrđeno je patvorenje u 3 uzorka mlijeka. Patvorenje mlijeka s dodatkom rekonstituiranog mlijeka u prahu, nije utvrđeno niti u jednom analiziranom uzorku. Na osnovu dobivenih rezultata, može se zaključiti da je važno provođenje kontrole ispravnosti označavanja, kao i kontrole patvorenja mlijeka zbog sprječavanja prijevara u poslovanju s hranom i obmane krajnjeg potrošača.One of the crucial tasks in the field of protection of the society is developing methods for the purpose of preventing occurrence on the product market, which do not correspond with legislation. Hence, there is a constant need for the development of quick and reliable methods in controlling the accuracy of food products. Frequently, in the Dairy industry, powdered milk is reconstructed because of its expired date and added to the pasteurized or sterilized milk and without it being rightfully labelled is put on the market, misleading the consumers. The consumers have the right to know what can be found in their food, while the manufacturers are obliged to inform and not mislead about the ingredients of the product; the characteristics of the food, especially its natural state, its identity and origin, its properties, its quantity, its durability as well as the process of production. The aim of this paper was to check validation of the labelling of the store-bought milk and to ascertain possible adulterating by adding powdered milk. The samples for this paper were purchased from retailers. Determining of the possible adulterating milk by adding powdered milk was carried out with the modified spectrophotometry, while the accuracy of its labelling was verified by the physical chemistry method in The Reference laboratory for milk and dairy products, Department of Dairy Science, University of Zagreb Faculty of Agriculture. Based on analysed samples of milk we got the following data. Of 15 samples in total, only 4 samples match formal legislation and given values on the product’s label. Furthermore, by analysing a freezing point as a way of controlling the adulterating of milk with water, the adulteration has been established in 3 samples. Adulterating milk by adding reconstructed powdered milk has not been stated in any analysed sample. As we can see from obtained results, it is essential to establish control of authenticity of labelling along with control of adulteration of milk to prevent falsehood when dealing with food and deceit of the consumer