تحديد بعض المعادن الثقيلة والتلوث البكتيري في الحليب الخام والمستورد المجفف == Determination of Some Heavy Metals And Bacterial Contamination of Raw And Imported Powder Milk
Author name:
مروة صباح طالب
Supervisor name:
محمد نافع علي العزاوي
General topic:
Biology
Specific topic:
Plant
Degree:
Master
University:
University of Baghdad
Language:
English
University location:
Baghdad
First pages:
24T2685 - p.pdf
Abstract:
يتعرض الحليب للعديد من الملوثات الفيزيائية والكيميائية والبيولوجية وذلك بسبب طرق الانتاج واسلوب النقل وعمليات التسويق ومن هذه الملوثات المعادن الثقيلة والرقم الهيدروجيني ودرجة الحرارة والبكتيريا. وقد صممت الدراسة الحالية لفحص عينات للحليب الخام التي جمعت | Milk is subjected to various physical, chemical and biological pollutants duo to producing, transporting and marketing processes such as certain heavy metals, pH, temperature and bacteria. The current study was designed to examine fresh milk samples were collected randomelly at early morning from six different locations at a rate of once each month during study period which commenced in October 2013 and ended in march 2014 and powder milk brands which were examined again for six months as in case of fresh milk where these milk brands were collected from local markets each month. The results of heavy metals showed that : • The investigation of Lead content in raw milk revealed that the highest mean value (1.801±0.311 ppm) was scored in Abo - Ghraib sample and the lowest mean value (0.941±0.104 ppm) was observed in Ghazaliya sample. For the Cadmium content in raw milk that the highest mean value (1.532±0.124 ppm) was found in Abo - Ghraib sample and the lowest mean value (0.063±0.044 ppm) was found in Fal'loga. The Copper content in raw milk also investigated and resulted the highest mean value was (0.931±0.092 ppm) in Azizia milk sample and almost similar value (0.931±0.301 ppm) was found in Madain sample while the lowest mean value was (0.308±0.029 ppm) in Fal'loiga sample. The highest mean value of Potassium in raw milk was recorded in two samples in Azizia (9718.8±246.6 ppm) and (9718.3±482.2 ppm) in Abo - Ghraib but the lowest mean value (4156.3±268.3 ppm) was recorded in Essaouira. Regarding Sodium content in raw milk, the results have found that the highest mean value was (2968.8±312.2 ppm) in Essaouira sample while the lowest mean value was (1432.5±156.8 ppm) in Abo - Ghraib. The Chloride content in raw milk samples, the highest mean value was (3053.0±128.6 ppm) recorded in Fal'loga sample and the lowest mean value was (639.0±198.4 ppm) was found in Azizia sample. Analysis of variance of these data showed significant effects (P?0.001) of both sampling sites and collecting months on milk (pb, Cd, K, Na and Cl) contents while analysis of variance of these data reveals no significant impact of sites on milk Cu content (P> 0.05) where no differences were observed between mean value of different collecting sites but shows highly significant (P? 0.001) effects of collecting months.• While powder milk has shown that the highest mean values of Lead (1.225±0.052 ppm) were found in Al - Mudhish brand and the lowest mean value (0.088±0.002 ppm) was detected in Anchor. The highest mean Cd value was (0.184±0.005 ppm) in Nido brand and the lowest mean value was (0.069±0.003 ppm) in Altunsa sample. While the highest mean value of Copper was (1.656±0.254 ppm) in Dielac powder brand and Anchor milk brand had the lowest copper mean value which was (0.767±0.014 ppm). The concentration of Potassium was (9625.0±462.9 ppm) which is the highest recorded in Dielac milk sample and the lowest mean value (3356.8±225.6 ppm) was found in Al - Marai milk sample. While the highest average of Sodium was (2625.0±342.6 ppm) scord in Dielac brand and the lowest average was (1745.0±338.4 ppm) recorded in Al - Marai sample. The highest mean value of Chloride (193.0±41.0 ppm) was recorded in Nido milk brand and the lowest mean value (122.7±22.2 ppm) was found in Altunsa milk sample. However, analysis of variance shows significant differences (P?0.001) between examined milk brands while no such differences were found between these brands (P>0.05) regarding collecting months.From the above results, it seems that the highest content of (Pb, Cd and Cu) are higher than those of standards of the International Dairy Federation (IDF) while contents of (K, Na and Cl) are within the standard requirement according to National Research Council (NRC).Microbial tests of raw milk samples were positive for bacterial growth, as different bacterial species were observed such as Lactobacilli spp. 63.8%, Streptococcus spp. 61.1%, Staphylococcus aureus 44.4%, Escheritia coli 88.8%, Bacillus spp. 72.2%, Salmonella typhi 72.2%, Staphylococcus epidermidis 30.5%, Pseudomonas spp. 47.2%, Micrococcus spp 27.7%, Clostiridia spp. 66.6%, Enterococci spp. 11.1% and K. pneumonia 75% from bacterial contamination of raw milk samples.However, only (11.1%) of the total collected samples of raw milk were suitable for human consumption and (88.9%) unsuitable, indicating that the source of infection or contamination of milk may be due to the animal health, human handler and the environmental factors, e.g., contaminated vessels, polluted water, flies and dust, etc… Obviously, bacterial contamination test of powder milk samples was carried out and negative results were obtained. However, it seems clearly that the opportunity of finding bacterial contamination in powder milk samples may be very rare since milk powder is produced in well designed and modern techniques. Nevertheless, a single bacterial contamination test has indicated to a positive growth of Staphylococcus aureus colonies.
