Abstract
Background/Objectives: Improving food safety practices among young adults is critical to public health, but effective communication strategies are under-researched. This study investigated the effectiveness of a 12-day message-based intervention to promote safe food handling practices using a randomised controlled trial. Methods: A total of 588 participants (aged 18 to 35 years) were randomly assigned to one of four experimental conditions or to a control group. Participants in the intervention groups received daily messages via a mobile app, while the control group received no messages. The intervention combined belief-based content to raise awareness with skill-based content to teach practical food handling, framed by either positive or negative emotional appeals. The experimental conditions differed in message congruence, with belief-based and skill-based content framed either consistently (both positive or both negative) or inconsistently (one positive, one negative). To assess the impact of the intervention, self-reported adherence to food safety practices, food safety awareness, and self-efficacy were measured at baseline and post-intervention. Results: The results showed that the intervention significantly improved food safety practices, especially when the messages were congruent in valence. Pre-intervention self-efficacy moderated the effects, with higher self-efficacy increasing receptivity to certain messages, while lower self-efficacy benefited from a different framing. Self-efficacy, but not awareness, mediated behaviour change, highlighting its key role in the success of the intervention. Conclusions: These results emphasise the importance of message valence congruence and individual self-efficacy levels in designing effective food safety interventions. Future research should investigate long-term intervention effects, adaptive mHealth strategies, and tailored communication approaches to maximise engagement and sustained behaviour change.