In February, the company in Castelnaudary in south-west France was accused of knowingly selling horsemeat as beef.
The meat was then sold to French firm Comigel, which produced nearly five million frozen ready meals for 28 different firms in 13 European countries.
Many of Spanghero’s clients ditched the supplier after the scandal broke, causing the factory to lose 200,000 euros a week, according to union officials.
Spanghero’s owner, the Basque cooperative Lur Berri, put the factory up for sale in April.
Marie Favié, a representative for the CFE-CGC union, said eight expressions of interests have so far been filed to the administrator, but this does not necessarily mean that there is a concrete buy-out plan on offer.
240 jobs at the factory are at risk.
Favié said a plan detailing job cuts will be unveiled on May 28.