Final answer:
Potential bias in the flavonoid study could stem from its funding by a candy company and a chocolate manufacturers association, which could be mitigated by independent funding and peer review.
Step-by-step explanation:
The study suggesting that regular consumption of foods rich in flavonoids, such as chocolate, may reduce the risk of coronary heart disease has a potential source of bias due to its funding by a candy company and a chocolate manufacturers association. This financial support may lead to biased outcomes that favor the interests of the sponsors. To avoid such a bias, the study could have been funded by an independent organization with no vested interest in the results. Moreover, the research methodology should be transparent, and the study should undergo peer review by experts in the field who do not have a conflict of interest.