Jwan Khaled Mohi Khaled* (1) ,Mufaq Mahmoud Ahmed (1),and Ghanim Mahmood Hasan(1)
(1) Faculty of Agriculture and Forestry, University of Mosul, Iraq.
(*Corresponding author: Dr. Jwan Khaled, E-mail: Jwan.khaled84@gmail.com).
Received: 14/03/2022 Accepted: 1/08/2022
Abstract:
The was used as the killing rate reached 100% for the three bacteria compared to the flow rates of 2 and 3 L/min. in which the killing rate was less. On the other hand, UV dose of 69 mJ s-1 ml-1 was the best as the killing rate was 100% for all types of bacteria. The purposes of this study were to investigate the effect of ultraviolet (UV) radiation at doses of 23, 46, and 69 mJ s-1 ml-1 and flow rates of 1, 2, and 3 L/min on microorganisms and on some mycotoxins in pasteurized bovine milk (3% fat) and skimmed milk and in raw milk. Aflatoxin B1 (AFB1) and ochratoxin A (OTA) were added at known amounts to 3% fat milk and skimmed milk and passed through the UV unit at a dose of 69 mJ s-1 ml-1 and the residual toxins were determined using the ELISA technique. Results showed that the UV radiation decreased AFB1 and OTA by 66.5 and 71.5, respectively, in 3% fat milk at a flow rate of 1 L/min, and OTA by 83% in skimmed milk. In raw milk, however, aflatoxin M1 (AFM1) and OTA were detected as contaminants, and the UV radiation resulted in 82 and 77.7% reduction, respectively, under the same conditions. This appeared to be a good result as the UV radiation decreased these mycotoxins to acceptable levels. In the effect of UV radiation on microorganisms in raw milk study, three bacteria were detected in raw unpasteurized milk and those were S. aureus, L. monocytogenes, and E. coli and their counts were 0.5×105, 1.0×105, and 2.0×105 CFU/ml, respectively. After milk samples were passed through the UV unit at 23 mJ s-1 ml-1 at the three flow rates the Listeria bacteria did affect and the killing rate was 0%, while the killing rate of coli bacteria was near 50% at flow rate 2 L/ min. When UV radiation dose of 46 mJ s-1 ml-1 was used, it was more powerful especially when the flow rate of 1 L/min.
Key words: ultraviolet rays, milk, E. coli, S. aureus, L. monocytogenes, S. typhi, aflatoxin, and ochratoxin.
Full paper in Arabic: pdf