A common recommendation for addressing the serious issue of foodborne illness is to train foodservice managers to handle and store foods safely. Typically, food safety education is considered successful when managers become certified through such programs as ServSafe^®, which is offered by Cooperative Extension and other organizations. However, sustained behavior change has been limited. The research contributed to understanding the nature of the limitations of current programs, toward betterment of food safety education. The goals of the research was to describe the type and extent of conceptual understandings possessed by trained and certified foodservice workers of scientific principles relevant to preventing foodborne illnesses, specifically, the role of heat and thermal dynamics in cooling foods. The theoretical framework informing the research combined science education's conceptual change model and adult education's transformational learning theory. Both theories posit that knowledge is more widely applied, more easily transferred to novel contexts, and more robust when learners develop conceptual understandings of scientific concepts versus algorithmic, rule-based knowledge. Both theories emphasize the necessity of learners connecting new knowledge to prior knowledge, experiences, and personal perspectives. Applying these theories to food safety curriculum and instruction had been explored very little. Methods included semi-structured interviews (with visual prompts and physical models), observations, document analysis, and concept mapping with 18 cooks at two Midwest hospitals. The study confirmed that neither managers nor workers were able to convey an understanding of cooling beyond routine practices associated with on-the-job training. Overlaid with Bloom's taxonomy of the cognitive domain, data also showed that understandings of the role of heat in cooling was situated at lower levels compared to knowledge about heat in cooking. Consistent with adult education literature, employees' personal identity as a 'cook' strongly influenced food safety knowledge and practices. Results explained, in part, the poor uptake of conventional training. Recommendations included increasing employees' motivation to learn scientific concepts by tapping their desire to be better cooks instead of forcing a new identity of ‘food safety workers'; increasing problem-solving abilities across contexts by teaching principles instead of rule-based behaviors; and involving all employees, not just managers, in food safety educational experiences.