Final answer:
Carbohydrate fermentation in lab tests typically presents as a yellow color with potential gas production, such as CO₂ bubbles. The yellow color indicates an acid reaction from fermentation, and gas production can be observed by bubbles or cracks on the agar surface. The correct option is A) Yellow Color and Gas Production
Step-by-step explanation:
The appearance of carbohydrate fermentation in a bacteriological test is indicated by a change in color and the potential production of gas. The typical result of a positive carbohydrate fermentation test is a yellow color and the possible presence of gas bubbles, such as carbon dioxide (CO₂), which are byproducts of the fermentation process.
For instance, in a Triple Sugar Iron (TSI) slant test, an acid reaction in the butt of the tube, indicating fermentation, would be shown as yellow coloration; if there is also gas production, this might be indicated by the presence of bubbles or cracks in the agar.
Some specific tests, such as the fermentation of mannitol by Staphylococcus aureus, result in a yellow color due to acid production from the fermentation process. In contrast, non-fermenters like Salmonella and Shigella species do not produce this change in color.
It's important to note that the production of certain types of gas during fermentation is used as an indicator of the fermentation of specific carbohydrates and helps in the laboratory identification of bacteria. The correct option is A) Yellow Color and Gas Production