產品名稱：MANNITOL SALT AGAR
貨號：oxoidL CM0085
規格：500g
MANNITOL SALT AGAR
Code: CM0085
Description：
A selective medium prepared according to the recommendations of Chapman1 for the isolation of presumptive pathogenic staphylococci. Most other bacteria are inhibited by the high salt concentration with the exception of some halophilic marine organisms. Presumptive coagulase-positive staphylococci produce colonies surrounded by bright yellow zones whilst non- pathogenic staphylococci produce colonies with reddish purple zones.
Mannitol Salt Agar is recommended for the detection and enumeration of coagulase-positive staphylococci in milk2, in food3 and other specimens4.
Oxoid Mannitol Salt Agar has been used for the examination of meat or fish5,6,7,8,9.
The addition of 5% v/v Egg Yolk Emulsion SR0047 to Mannitol Salt Agar enables the lipase activity of staphylococci to be detected as well as mannitol fermentation10. The high concentration of salt in the medium clears the egg yolk emulsion and lipase production is detected as a yellow opaque zone around colonies of staphylococci which produce this enzyme.
Technique
Heavily inoculate the Mannitol Salt Agar plate and incubate for 36 hours at 35°C or for 3 days at 32°C - the latter is recommended by the APHA3.
Presumptive coagulase-positive staphylococci produce colonies with bright yellow zones whilst coagulase-negative staphylococci are surrounded by a red or purple zone. Pick off suspect colonies and subculture in a medium not containing an excess of salt （e.g. Nutrient Broth No.2 CM0067） to avoid interference with coagulase or other diagnostic tests.
Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared plates at 2-8°C.