Why is it important to keep foods at proper temperatures during outdoor events?

Keeping foods at proper temperatures during outdoor events is crucial primarily to prevent the growth of bacteria. Temperature control is a key factor in food safety, as certain conditions can facilitate bacterial growth, leading to foodborne illnesses. When food is left in the temperature "danger zone" (between 41°F and 135°F), bacteria can multiply rapidly, increasing the risk of contamination.

While enhancing the presentation and ensuring that foods look appetizing are important considerations for serving food at events, they do not directly address food safety. Compliance with aesthetic standards is also relevant in terms of visual appeal, but this does not impact the safety or edibility of the food itself. Therefore, the focus on maintaining proper temperatures directly relates to health and safety, making it the most critical reason among the options provided.