At the end of last year, the University of Michigan became one at least a dozen universities in the US and Canada to ban Coke from its campus, because of concerns over labour rights in Colombia. Others to do so include New York University, Rutgers University in New Jersey, Santa Clara University in California and Salem State College in Massachusetts.
Several European universities have also cancelled contracts with Coke, including St Hilda and Balliol, Oxford, and Trinity College in Dublin.
The Columbian issue dates back 16 years, when a union leader was murdered at a bottling plant -- one of eight murders of union leaders that took place between 1989 and 2002. Campaigners argue that Coke has failed to investigate the murders or deal with wider issues over the abuse of its workforce.
Meanwhile, a recent protest by villagers near a Coke bottling plant in Northern India has also landed the soft-drink maker in trouble. Residents of Kala Dera, in Rajasthan, want the plant closed because they say that it uses up scarce water resources.
Now, according to the Financial Times, Coke has set up a task force to defend itself against these claims of wrongdoing in Colombia and India. It has also published a report it commissioned last year on its Colombian operations in an attempt to prove that there was no ongoing abuse of its workforce.
The problems come as Coca-Cola plans a global ad campaign using the strapline "welcome to the Coke side of life". It recently appointed Wieden & Kennedy/Amsterdam to handle the brand globally.
Tom Pirko, president of beverage industry consultancy BevMark, told the FT: "One of the things at the heart of the Coke brand is that it embodies goodness, fun and play. If consumers start to associate the brand with more negative messages, that is a very big problem for Coke. It is impossible to over-estimate the damage caused when a brand goes from being seen as something good to something bad."
Meanwhile, in the UK, Channel 4's nutrition guru Gillian McKeith named fizzy pop as her number one offender in a list of her 12 worst foods and drinks.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the Forum.