I would like to determine LAB and total anaerobic bacteria in vacuum packed fish. What are the best medias and incubation parameters?
Hi IIknar,
For lactic acid bacteria you can use MRS agar with incubation at 37 degree Celsius for 3 days in an anaerobic chamber. I am not sure about total anaerobic bacteria.
Please find attached one of my recent paper for further details.
Monil
Hi Ms
You can lactic acid bacteria determine was used MRS or M17 after dilution for samples and trans 1 ml from two last dilution to Pitre dish and pour 12 ml from media incubation at 32 c for 24-48hours in anaerobic conditions .LAB numbers count after incubation
Total anaerobic bacteria is tricky. I would use a couple different media; one with carbohydrate like Trypticase soy agar and one without. They should both have some hemin added to them and grow one set of plates in GasPak jars and another set open in the incubator to determine total aerobic-facultative bacteria. This should give you a rough idea of total anaerobic bacteria that will grow in this system (after you subtract out the number of aerobic-facultative bacteria).
While by aerobes you already specify the final electron aceptor (oxygen), and it usually refers to heterotrophic aerobes so, it indicates their main energy requirements.
With anaerobes... well, things are way more complicated, you only indicate that they can live without oxygen. The electron acceptor can be nitrate, Fe(III), Mn(IV), CO2, U(VI), organic acids, highly chlorinated compounds, sulfate, sulfur,... and I'm only talking about anaerobic respiration leaving fermentations aside
You can use MRS and M17 media for lactic acid bacteria using pour plate method, incubation at 37C/ 48-72h. While for total anaerobic count, may be meat liver agar/ Reinforced Clostridium agar/ Trypticase soy agar can be used. It should be pour plated and it get solidified, overlayed with same media would be more beneficial to prevent growth of aerobic bacteria from the sample. and finally incubate with GasPak in closed anaerobic jars/ CO2 incubator. We usually followed this method, hope it may help you, too.
Best wishes
I agree with Jay Sperry. The (second) agar without sugar can be Heart Infusion Agar or Columbia Agar.
Tomato Juice Agar is good for lactobacilli.
use robertsons cooked meat medium for anaerobes isolation.
try roll tube method with minimal media and sparging hydrogen gas
For lactic acid bacteria the suitable method explained before by Alaa and Jay are suitable. For anaerobic bacteria I suggest to test the TSN (Thiosullfate Neomycin Agar) more suitable as you strike on agar end incubate with GasPak in closed anaerobic jars/ CO2 incubator for at least 48h. Dark black colonies should be detected.
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