Improving the communication of uncertainty in food safety on social media: a content analysis of aspartame risk messages

Background Although social media has become a primary platform for the public to access and disseminate risk information, research on how to effectively communicate food safety uncertainty on these platforms remains limited. Objective To explore the impact of uncertainty frames, information sources, and persuasive strategies on public engagement, we conducted a case study of aspartame risk communication on Weibo. Methods Content analysis was conducted on 1,863 Weibo posts related to aspartame. Uncertainty frames, information sources, and persuasive strategies were manually coded. Public engagement was measured by retweets and likes, and descriptive statistics, chi-square tests, and negative binomial regression were conducted. Results Results revealed a lack of professional voices, with only 23.0% of posts originating from professionals and medical institutions. Messages predominantly relied on the technical uncertainty frame (37.6%), which significantly diminished engagement ( p < 0.001). However, when combined with persuasive strategies such as anecdotal evidence ( p < 0.001) or cues to action ( p < 0.001), this frame enhanced engagement. Moreover, appeals to authority generally reduced engagement ( p < 0.001), whereas cues to action tended to enhance engagement across various uncertainty frames ( p < 0.001). Hard science contributed to higher engagement only in the context of consensus uncertainty ( p < 0.001). Anecdotal evidence and fear appeals exhibited more complex effects on engagement. Conclusion The findings suggested that food safety risk communication on Weibo requires greater involvement of expert voices. When framing aspartame risks under different types of uncertainty, communicators should carefully select appropriate persuasive strategies to improve communication effectiveness.