EU countries voted in February to approve the use of the enzyme, but the issue will now be decided in parliament after Westlund's resolution was approved by 31 votes in favour and 21 against.
"I am pleasantly surprised. There is now a good prospect that this will be upheld by the European Parliament as well. Consumers would then avoid being fooled," Westlund said.
Sweden voted in favour of approving the use of thrombin in early February, a decision which drew criticism from consumer groups and politicians alike who fear that consumers stand to be misled.
"We do not want this at all - it is meat make-up," Jan Bertoft at the Swedish Consumer's Association (Sveriges Konsumenter) said at the time.
Thrombin is a coagulation protein which together with the fibrous protein fibrin can be used to develop a "meat glue" enzyme that can be used for sticking together different pieces of meat.
Westlund's resolution argues that the use of thrombin heightens the risk of bacterial growth.
Despite clear labelling of meat products, there remains a concern that consumers will be fooled as it is not clear from the appearance of the product whether it is constructed from different pieces of meat or not.
"To use thrombin in meat is a way of misleading consumers, to present something as better than it actually is," Westlund said after the February decision.
Åsa Westlund has been involved in the process of developing new EU legislation covering food additives, which will come into force in the beginning of next year, and believes that thrombin would not have been approved had these new rules already been adopted.
But Gunilla Henrysdotter at the Swedish National Food Administration (Livsmedelsverket) has argued that it is not certain the new legislation would have rendered thrombin illegal.
The decision to approve thrombin was taken by a Standing Committee on the Food Chain and Animal Health (SCFCAH) on February 9th. One country voted against and one abstained. All the other countries, including Sweden, voted in favour.
According to the committee decision, products containing thrombin should be clearly marked with the text "composite meat product."
Thrombin can be made from blood taken from either cows or pigs, and this information must also be clearly shown.
Products containing thrombin would not however be approved for use in commercial kitchens, a ban that Åsa Westlund argues the current legislation made easy to circumvent.