Burglars doused a house with bleach after stealing jewellery and electronic goods in Dunstable Road on Thursday.
Five men forced their way into the house and threatened the occupants before taking gold jewellery, an iPod and Sony camera.
They then poured bleach and disinfectant everywhere before fleeing the scene.
Det Con Denise Comb said: “The men are all described as Eastern European, wearing balaclavas. One was 26-35 years old, with a round face and round nose, another was 26-35 years old with a long face and blue eyes.
“This incident happened during the early evening and as this house is on a busy main road it is possible the pedestrians or motorists saw a group of men running from the scene. I would urge anyone who saw or anyone who has information about this crime to come forward and speak with officers.”
Call Det Con Comb in confidence, on 01582 394359, or Bedfordshire Police on 101, or text information to 07786 200011.