NaCl

Introduction Results Methods Photos

Introduction

Environments containing high concentrations of sodium chloride are selective against most common bacteria. [Why is this?] We have two high salt culture media that can be used to test your unknown organisms: 7% NaCl Agar Plates and 6.5% NaCl Broth.

 

Results

+7% = Positive. Growth on 7% NaCl agar (Note: an organism that grows in 7% NaCl should also grow in 6.5% NaCl.)
-7% = Negative. No Growth on 7% NaCl agar
+6.5% = Positive. Growth in 6.5% NaCl broth
-6.5% = Negative. No Growth in 6.5% NaCl broth.

Methods

1. Obtain a medium with the appropriate NaCl concentration (determined by the organisms you're trying to distinguish among).

2. Inoculate using aseptic technique (streak for isolation if you're inoculating a 7% agar plate).

3. Incubate at appropriate temperature (whatever temperature your organism grows well at). Incubate for 24 to 48 hours.

4. Obtain your plates and look for presence/absence of growth.