Heat oil in large pan, add seeds and spices, cook, stirring, until fragrant.
Add tomatoes, onions, salt, garlic, raisins, sugar and vinegar.
Stir over heat, without boiling until sugar is dissolved.
Simmer, uncovered, stirring occasionally, about 35 minutes or until mixture is thick.
Stir in rhubarb, simmer, uncovered, stirring occasionally, about 5 minutes until rhubarb is tender.
Spoon hot chutney into hot sterilised jars; seal immediately.