The gap between science and reality when it comes to public perceptions of food safety has been on full display in recent days. In a development that should send chills down the spine of any food or ingredient manufacturer, a subset of the beef business with an apparently spotless food safety record has been decimated by the social media and popular media sources spreading the “pink slime” tag on a product that is lean finely textured beef.

Makers and users of bisphenol A, a product used to make durable plastics and for liners in cans, won what may have been a pyrrhic victory when the Food and Drug Administration said scientific evidence needed to justify banning the use of B.P.A. simply does not exist.

Ban or not, a number of prominent users have halted the use of B.P.A., most notably makers of toddler sipping cups and bottles. In March, Campbell Soup Co. said it would phase out the use of B.P.A. in some of its soup cans.

Regardless of the science, B.P.A. now has a taint that will be difficult to shake. It wasn’t long ago that it was the 24-hour news cycle that made companies fear a public relations threat to their products. But the mainstream media seems almost like a quaint relic when considering the pink slime furor.

Years after a print story about lean finely textured beef led restaurant chains to stop using the product, the latest craze was triggered and spread through social media and later picked up by television and print sources. The B.P.A. and lean finely textured beef episodes unfolded in very different ways from one another, but both serve as reminders of the importance of companies and industries girding themselves for attacks that often are sudden, unpredictable and brutal.