After years of wrangling and a ruling by the EU's top court, the European Parliament agreed Wednesday that pollen is a constituent of honey and not an added ingredient.

The distinction may seem arcane but it has important implications for the industry since it determines how honey jars are labelled when it comes to levels of pollen from genetically modified plants.

Purity is a key selling point for honey and a label warning consumers it contained GMO pollen might deter buyers anxious to avoid foods that have been genetically altered.

Lawmakers voted 430 for and 224 against to define "pollen as a natural constituent of honey, rather than an ingredient," said a Parliament statement.

"This means that GM pollen has to be labelled if it makes up more than 0.9 percent of the honey" by volume under current EU rules on GMO content, it said.

However, the statement noted that since normally pollen content never tops 0.5 percent, "it would never exceed the labelling threshold."

In 2011, the European Court of Justice ruled that pollen was an ingredient in honey and therefore would need to be listed as such in labelling.

In the case of an ingredient, the 0.9 percent GMO threshold applies to the total pollen rather than the total honey.

The EU imports about 40 percent of its honey, with half coming from Latin American countries such as Argentina and Mexico where GMO maize and other crops are common.

Green groups criticised the vote as helping promote GMO crops at the expense of beekeepers and consumers who want purity above all in their honey.

The Commission, the EU's executive arm, "must not underestimate the problem of GMOs; producers in Latin America, Canada and China should be forced to carry a GMO label," Hungarian Socialist MEP Csabal Sandor Tabajadi said.

British Conservative Jilie Girling, who steered the proposal through parliament, said it was unrealistic to expect producers to do so and would be an additional burden on them.

The proposal now goes forward for discussion with individual member states who will determine its final form.