What temp to E. coli and Salmonella die at?

Question

I'm doing an Ames Test, but my top agar is not melting at 47 C like it should. How high can I heat it to melt it without killing my bacteria?

Sorry, that should be "do" not "to."

Answer 1

Bacteria can multiply at temperatures between about 33.34° F (1° C) and 125° F (52° C). They will easily survive temp around 55-60C. They grow best at human body temperature (98.6° F, 37° C) and can divide 2 to 3 times per hour. They divide rapidly at 80° to 105° F (27° to 41° C). But at non-optimal temperature they will still survive. In fact, sterilization need very high temperature (above 120C) to make sure that all bacteria will die.

Answer 2

Hi,

Unfortunately, I think you may need to start over if you can. Generally, the top agar is melted and sterilized at the same time by autoclaving at about 121C. Then, it is cooled and kept molten in a bath at 45-47C. So, if your top agar wasn't already molten, I don't think it will ever melt at 47C.

You could try waiting to see if it melts, or you could try heating it a bit hotter to see if it melts (maybe up to 55C), or you could try pouring it anyways to see what sort of results you get. But none of these seem likely to be a good solution.

So I guess the only real thing to do is to start over and autoclave the agar before adding the bacteria. Sorry! Good luck.

Answer 3

When I would make different kinds of agarwe would always boil and melt the solution before autoclaving, then the would be set on 121 degrees for a certain amount of time depending on the amt of agar you had. For exp.if you had 1liter or less it would be 15 minutes. 10 liters would be 60 minutes.

Answer 4

How about put in freezer let say minus 30 degree Celsius. Will they die or just not active?

Answer 5

I need to design a HotSmart Plate that kills both bacteria (this is possible, but what about salad?)

Answer 6

usually killed at 600 degrees