Effect of solar drying using a natural convective solar drier on bacterial load and chemical composition of bayad (Bagrus bayad) fish flakes

Solar drying experiments of bayad (Bagrus bayad) fish flakes using a natural convective solar drier were conducted at Food Research Centre (FRC), Agricultural Research Corporation, Shambat, Sudan. During June-August, 2008 and MayJune, 2009. Tthe objectives of the present study were to investigate the effect of solar drying using a natural convective solar drier on bacterial load and the percentages (%) of chemical composition of bayad fish flakes. These are percentages of fats, protein, fibers and ach contents .The results showed that, there was a considerable decrease in bacteria present in the dried fish compared to the fresh one from the same fish. this could be attributed to the increase in temperature inside the solar collector of the drier . The total viable count of bacteria decreased from (1.13×10 8 cfu⁄g) in fresh fish to (2.16×10 6 cfu ⁄g) in solar dryed fish. This means that, solar drying of fish affected bacterial load considerably due to the elevated temperature inside the solar drier. Regarding chemical compositions of fish flakes, the results showed that, the amount of fats as a percentage were similar in both fresh and dried fish flakes, fibers content were nil in both fresh and dried fish, while protein content was less in dried fish flakes .Ach content was increased in dried fish from 7.27% to about 30.68%.The increase in ach and decrease in protein were resulted from the addition of salt as a pre-treatment before fish were dried, so that the percentage of inorganic matter was increased (salt) and the percentage of organic matter was decreased (protein).