Nitrates and nitrites pollution in cheese and concentrated milk

ABSTRACT

Twenty five different cheese samples and ten concentrated milk samples were randomly collected from different localities of Zagazig City. Sharkia Governorate. The collected samples were analysed colorimetrically for nitrates and nitrites by using spectrophotometer. The obtained results revealed that the average concentration of nitrates was 86.61, 123.92 and 130.86 mg/kg in skimmed milk, Domiati and full cream soft cheeses samples respectively, while processed and hard cheese samples contained an average concentration of 50.21 and 26.58 mg/kg respectively. The average concentration of nitritesis, skimmed milk, domiati and full cream soft cheese was 1.77, 2.014 and 1.64 mg/kg respectively. Meanwhile, processed and hard cheese exhibited nitrites with an average concentration of 0.81 and 4.27 mg/kg. The examined milk powder and condensed milk samples having an average concentration of 150.62 and 146.32 mg/kg for nitrates, while nitrites was 1.04 and 1.79 mg/kg in milk powder and condensed milk. The most analysed samples contained nitrates above the desirable limit [50 mg/kg] recommended by and Stephany et al. [1978] and Bertelsen [1979]. In contrast nitrites were within the desirable limit [2 mg/kg] in most of the analysed samples with the exception of domiati and hard cheese samples. The results of this study indicate that presence of nitrates and nitrites above the desirable limit in milk and milk products act as heath hazard for man consuming such contaminated products