Which of the following is a critical factor in ensuring food safety?

Staff training on food safety is a critical factor in ensuring food safety because it equips employees with the necessary knowledge and skills to handle food properly, thus preventing foodborne illnesses. Trained staff understand the importance of personal hygiene, proper cooking temperatures, cross-contamination prevention, and safe storage practices. This foundational knowledge is vital in creating a culture of food safety within a food establishment, leading to consistent and safe food handling practices.

In contrast, while frequent menu changes, reduced inventory levels, and using frozen ingredients can introduce their own challenges concerning food safety, they do not have the direct impact that staff training does. Frequent menu changes may lead to confusion among staff regarding new items and their safe handling, while reduced inventory levels and frozen ingredients can relate more to operational efficiency than to immediate food safety practices. Therefore, robust training remains paramount in maintaining high food safety standards in any food service operation.