Do most pathogenic bacteria require an aw (water activity) level of 0.89 or above to multiply?

Most pathogenic bacteria indeed require a water activity (aw) level of 0.89 or above to multiply effectively. Water activity is a measure of the water available in food for microbial growth, and a level of 0.89 signifies a sufficiently moist environment for bacteria to thrive.

Most pathogens such as Salmonella, E. coli, and Listeria monocytogenes generally grow best at levels of water activity that are above this threshold. While some microorganisms can adapt to lower levels of water activity, pathogenic bacteria typically do not multiply effectively below this level.

The answer suggesting that the statement is false reflects a misunderstanding of the basic microbiological principles of food safety, as pathogenic bacteria largely depend on proper aw levels for growth. Understanding this threshold is crucial for preventing foodborne illnesses, emphasizing the importance of managing moisture levels in food preservation and safety protocols.