Different Agar - MicroBio

Question

Hi!

I wonder, when determining the amount of CFU/g in ground meat, why is it more better to use TGE agar (tryptone glucose extract agar) than other types of agar, such as nutrient agar?

Thanks!

Answer 1

Hi Lily P.,

As you could discover by looking up manufacturer's sales info for TGE, it works well for organisms commonly growing in (or growable from!) meat, dairy, water, sample etc.

These derive from contamination, e.g. by intestinal flora, during the butchering process.

Essentially, you're just giving them "more of the same", nutrient-wise, easy-to-eat rich food.

You're NOT trying to select them for ability to synthesize everything from basic raw materials, you WANT them to all grow (at this point).

And by the way, samples with some CFU count aren't necessarily awful -- yes, E. coli H57O157 (generates Shigella toxin) is a bad customer, but modern beef-raising conditions perhaps select for it -- and so far, I've had no issues with home-butchered venison.

-- Cheers, --Mr. d.