Facebook stores have a challenge when it comes to shopper trust, as more than half of online consumers do not think those stores are built to protect them against fraud, according to a new study by fraud prevention firm ThreatMetrix and think tank Ponemon Institute.

In an August survey of 722 shoppers who deemed themselves active online users, 53% said they distrust shopping in Facebook stores because of the fraud potential, while 23% said they are unsure whether the social network was safe for shopping. 24% of survey respondents say Facebook is doing enough to protect shoppers from fraud.

“With new account registration, you have [criminals] who will sign up with social networking sites like Facebook in order to gain access to current user information,” says Alisdair Faulkner, chief products officer at ThreatMetrix. “Having a comprehensive fraud prevention strategy is vital for social networks and strategic to their operations, especially if a user experiences spam directly within the site.”

The survey also revealed that shoppers have been slow to embrace Facebook as a place for shopping, as only one in five consumers say they have purchased something directly from a Facebook storefront. “Consumers have yet to adopt social shopping habits because it’s largely unavailable, with many retailers still trying to figure out their strategy in offering their products via social outlets like Facebook,” Faulkner adds. “And with the current consumer perception that Facebook isn’t doing enough to protect against security breaches, Facebook storefronts still face hurdles in gaining widespread adoption.”

When asked which company, Facebook or Google, was more effective at protecting shoppers against fraud and other abuses when shopping online, 51% said Google, 26% said Facebook, 13% said they were equal and 10% were undecided.

Google does not complete online transactions for shoppers, as its new social network Google + has no embedded storefronts and its comparison shopping engine, Google Shopping, directs consumers to retailer web sites when they click Buy.