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Научни трудове на Съюза на учените в България-Пловдив. Серия В. Техника и технологии, т. XV, ISSN 1311 -9419 (Print), ISSN 2534-9384 (On- line), 2017. Scientific Works of the Union of Scientists in Bulgaria-Plovdiv, series C. Technics and Technologies, Vol. XV., ISSN 1311 -9419 (Print), ISSN 2534-9384 (On- line), 2017.
INFLUENCE OF ALTITUDE IN SOME HEAVY METALS OF MILK
xXhavit Ramadani, 2Dilaver Salihu, 2Valbona Ramadani, 3Lorike Salihu
'Faculty of Agriculture and Veterinary; University of Prishtina "Hasan Prishtina", Prishtine, Bulevard "Bill Clinton", nn, 10000 Prishtine -
Republic of Kosovo. 2Faculty of Food Technology, University of Mitrovica"Isa Boletini",
Mitrovice - Republic of Kosovo. 3University of Chemical Technology and Metallurgy, Sofia, Bulgaria.
Abstract
Milk is one of the major sources of mineral substances. Within these substances, in very small concentrations and in trace, heavy metals are contained. The purpose of this study was investigation the influence of altitude in some heavy metals (Fe, Zn, Al, and Mn) in fresh milk. During 2016, fresh milk samples were obtained from nine dairy farms located in different areas of Kosovo with different altitudes, ranging from 389, 512, 582, 585, 636, 888, 1008, 1040 up to 1142 m. In each of the farms, five of dairy cows were selected, a total of 45 cows and in each of them, milk samples with a volume of about 200 ml were taken. Results were statistically analyzed using JMP 7.0 statistical package. Obtained results of the study showed that the altitude did not have a statistically significant influence on any of the heavy metals of the analyzed milk.
Key words: Milk, heavy metals, altitude INTRODUCTION
Milk and dairy products are one of the major sources of mineral substances (Iwegbue et al., 2008). Zamberlin et al., (2012) emphasize that the amount of minerals in milk is not constant and depends on the lactation phase, status of animal nutrition, environment and genetic factors. According to O'DellandSunde (1997), milk composition includes macro elements and microelements. In almost all foods, including milk and dairy products, within mineral substances, in very small concentrations and in trace, heavy metals are contained. According to Aslam et al., (2011), Malhat et al., (2012), heavy metals are elements that have a specific density more than 5 g/cm3. Heavy metals are essential for regular body metabolism, however the difference between their effective and toxic level is very small. Abdulkhalic et al., (2012) emphasize that heavy metals are persistent pollutants in environment and can cause serious environmental and health hazards. Milk
and dairy products are contaminated with heavy metals either through food and water or through production and packaging processes (Anastasio et al., 2006; Ayar et al., 2009). Pollution with heavy metals raises serious environmental concerns such as intake into food chain, which may be potentially harmful to human health (Namihira et al., 1993, Isaac et al., 2012). Determination of residual metal concentrations in milk can be an important "direct indicator" of the hygienic status of milk as well as an "indirect indicator" of the environmental pollution level, in which milk is produced (Licata et al 2004, González-Montaña et al., 2012). According to Rezaei et al., (2014), the presence of heavy metals emphasizes the need for regular monitoring and a more stringent food safety management system (FSMS) in order to control the heavy metals at the lowest possible levels.
The sources of the investigated literature on the influence of altitude in the concentration of heavy metals in milk have been mainly related to human milk, while for cow milk and other animals, scientific information has been mainly rare. For this reason, the purpose of this study was to investigate the influence of altitude in some heavy metals (Fe, Zn, Al and Mn) in fresh milk.
MATERIAL AND METHODS
During 2016, fresh milk samples were obtained from nine dairy farms located in different areas of Kosovo with different altitudes, ranging from 389, 512, 582, 585, 636, 888, 1008, 1040 up to 1142 m. In each of the farms, five of dairy cows were selected, a total of 45 cows and for each of them, milk samples with a volume of about 200 ml were taken according to IDF 50 B: 1985 standards (Grüner and Filajdic, 1993). Heavy metal presence was determined using a Thermo scientific (M-series) atomic absorption spectrometer with deuterium and Zeeman background correction equipped with acetylene/air flame (FAAS). Results were statistically analyzed using JMP 7.0 statistical package (SASS unit). The results of the analyzes are presented in tabullary form, and the statistical processing of the obtained results include determining the average value, minimum and maximum values, standard deviation, coefficient of variation and the P value of the significance between analyzed samples.
RESULTS AND DISCUSIONS
Results obtained this research are summarized in table 1., and the following conclusions drawn:
The highest concentration of zinc was observed in milk samples at altitude 389 m, with about 6.0009 mg/L, whereas the lowest concentration (2.9047 mg/L) was found at altitude 1142 m. An easy trend of decreasing values depending on altitude was observed, but statistically it was found that the differences between high points of altitude were nonsignificant (P=0.0130). Cow's milk normaly contains 3-5 mg/L of zinc. Moreover, the Recommended Dietary Allowance (RDA) of zinc is 8 mg/day for women and 11 mg/day for men (Mason, 2008). Results of this research regarding to this element are between limits prescribed by the author and this parameter.
The highest level of iron concentration resulted in altitude 1008 m (1.4150 mg/L), whereas the lowest level resulted in 1040 m of altitude (0.3146 mg/L), with an average of 0.6522 mg/L. This parameter also show an increase and decrease in values, with a very slight tendency to increase acording altitude, but the differences between points of altitude were nonstatistically significant (P=0.0376).
The highest level of copper concentration is contained in milk samples from the altitude 636 m. (0.2935 mg/L), followed by samples at altitude 1142 m. (0.1593 mg/L), whereas the lowest concentration is contained in milk samples from the altitude 582 m. (0.0412 mg/L), followed by altitude 585 m. (0.0828 mg/L). Average value of this parameter was 0.1139 mg/L. The normal amount of copper in milk varies from 0.5 to 0.85 mg/L (Jovic, 1963). According to (Mason, 2008), the RDA of copper is 0.9 mg/day for men and women.
Table 1. Concentration of zinc, iron, copper and manganese (mg/L) in milk depending on
altitude
Altitude (m) Zinc (mg/L) Iron (mg/L) Copper (mg/L) Manganese (mg/L)
389 6.0009 a 0.5690 b 0.1066 bcd 0.0467 bc
512 4.3980 abc 0.4314 b 0.1354 abc 0.0276 cd
582 3.2488 c 0.5363 b 0.0412 d 0.0343 bcd
585 5.2690 a 0.6290 b 0.0828 cd 0.0102 d
636 4.6996 abc 0.7612 b 0.1935 a 0.0599 abc
888 3.3802 c 0.4793 b 0.1232 abc 0.0649 ab
1008 5.2210 ab 1.4150 a 0.0995 bcd 0.0546 abc
1040 3.4381 bc 0.3146 b 0.0839 cd 0.0507 abc
1142 2.9047 c 0.7338 b 0.1593 ab 0.0825 a
Average 4.2845 0.6522 0.1139 0.0479
Min. 2.9047 0.3146 0.0412 0.0102
Max. 6.0009 1.4150 0.1935 0.0825
StDev 1.0890 0.3190 0.0452 0.0215
CV, % 25.4184 48.9079 39.6904 44.8822
P value 0.0130 0.0376 0.0116 0.0057
* Levels not connected by same letter in superscript are significantly different
Results of this research regarding this element are under the limits prescribed by the authors and this parameter don't exceed maximum allowed level for milk. In this element, also, the differences between diferent points of altitude were statisticaly nonsignificant, even though the very slight trend of increasing values in accordance with increasing altitude was registerd (P=0.0116).
The lowest concentration of manganese resulted in milk samples from points in altitude 585 m. (0.0102 mg/L). A litle bit higher concentration resulted in points of altitude 512 and 582 m. (0.0276 mg/L) respectively (0.0343 mg/L). The highest concentration of manganese is registered on the samples from altitude 1142 m. (0.0825 mg/L). In nine points of different altitudes, concentration of manganese did not show statistically significant differences (P=0.0057), even though a slight trend on increasing values in accordance with altitude was registered.
CONCLUSIONS
As a general conclusion on this research, it can be concluded that obtained results of the study showed an average values of analysed heavy metals of milk within the permissible limits. Analyzed milk in all altitude points can be considered as safe for consumption and processing. In order to determine the differences in heavy metals of milk depending on altitude, the results of the study showed that the altitude did not have a statistically significant influence on any of the heavy metals of the analyzed milk.
LITERATURE
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Corresponding author, e-mail: Xhavit Ramadani, xhavit.ramadani@uni-pr.edu
