Status of membrane-filter procedure in the examination of water and milk for Staphylococcus aureus.

A comparative study was carried out to assess the performance of four selective media, namely Baird-Parker (B-P), Mannitol-Salt Agar (M.S.A.), Staphylococcus-110 (S-110), and Chapman-Stone (C.S) in solid and liquid forms for recovery of Staphylococcus aureus from water and milk, using membrane filter technique. The descending order of efficiency for demonstrating the presence of inoculated S. aureus from unsterilized Nile water was (B-P)--(M.S.A) + (S-110) and (C.S) medium in solid form and changed to (S-110)--(M.S.A)--(C.S) when used in the liquid form. With sterile Nile water, the descending order of efficiency of the tested media was (B-P) + (M.S.A)--(S-110) and (C.S) medium in the solid form and (M.S.A) + (S-110) and (C.S) in the liquid form. In testing the inoculated milk using solid media, (S-110) and (M.S.A) tend to show similar results and took intermediate position between (B-P) and (C.S). When liquid media were used, the descending order of productivity was (S-110)--(M.S.A) and (C.S).