Coliform bacteria will produce gas in ________ broth at _______ within ______.

The correct answer indicates that coliform bacteria can produce gas in lactose or lauryl tryptose broth at a temperature of 35.5 degrees Celsius within a time frame of 24 to 48 hours.

Lactose broth is specifically formulated to support the fermentation activity of lactose by coliform bacteria, which includes organisms such as Escherichia coli and Enterobacter species. These bacteria metabolize lactose, resulting in gas production (usually carbon dioxide) as a byproduct. This is a fundamental characteristic used to identify coliform presence in water samples.

The chosen temperature of 35.5 degrees Celsius is ideal for promoting the growth of coliforms. It is close to the optimal temperature for these bacteria, enhancing their metabolic activity and ensuring accurate testing results.

The 24 to 48-hour incubation period allows sufficient time for gas production to occur, providing a reliable means of confirming coliform presence in the tested sample. This range aligns with standard microbiological practices for coliform testing, ensuring that any gas produced can be adequately observed and recorded.

In summary, the correct answer reflects the ideal conditions for culturing coliform bacteria in the laboratory setting to confirm their presence through gas production.