* EU-Japan free trade talks launched in March 2013
* EU wants Japan to open up to EU food and drink
* "What is sensitive in Japan about chocolate?" - Petriccione
BRUSSELS, Dec 17 (Reuters) - The European Union and Japan could forge a free trade accord within months, but failure to do so by the end of next year could lead to scepticism that a deal will ever be reached, the EU's chief negotiator said on Thursday.
The two launched negotiations in March 2013 towards a trade deal that would encompass a third of the world's gross domestic product.
Japanese Prime Minister Shinzo Abe and top EU officials called on negotiators in May 2014 to wrap up all key issues by the end of this year. Instead, a 15th round of talks is now scheduled to take place in Brussels at the end of February.
Mauro Petriccione, the EU's lead negotiator, said the talks were now "mature" in the sense that each side knows the other's position and now needs to find compromises.
"If we don't make it in 2016, we'll have to explain why, and we can't exclude a resurgence of the scepticism towards the possibility of an EU-Japan FTA that we had before we started," Petriccione told reporters at a briefing.
"In my judgment, it's perfectly possible from a negotiating point of view to do it in a few months."
Petriccione expressed exasperation over one major sticking point - the EU's demand that Japan open up its markets to European food and drinks. Tokyo is wary of doing so out of concern for the country's farmers, who are backed by the politically influential Japan Agricultural Cooperatives lobby.
"What is sensitive in Japan about chocolate? What is sensitive about spaghetti? We will be open on issues like rice, beef, pork, dairy products. But if you look into dairy products where's the problem in Japan for cheese?" he said.
"Japan starts from the point of view that anything that could upset the status quo in agriculture is inherently dangerous. If you start from the notion that you shouldn't upset the status quo, you shouldn't negotiate."
In the case of cheese, Japan has import tariffs of up to 40 percent. The EU has offered in return to cut its import tariffs for cars, typically at 10 percent, and for car parts.
Still, the conclusion in October of the Trans-Pacific Partnership between Japan, the United States and 10 other Pacific Rim nations shows Japan can forge trade deals.
In its talks with Japan, the EU wants import tariffs cut, non-tariff barriers to trade removed, access to public procurement, mutual recognition of protected food or agricultural products and a more open market for services.
Petriccione said the talks must make progress.
"We're fed up with 'keep going'. We've had some negotiations that have lasted for 20 years, and people are tired of it. We don't want to drag things forever," he said. (Reporting by Philip Blenkinsop; Editing by Hugh Lawson)