I think there is msiunderstanding among non muslim about Jakim halal certificate.
when business 100% owned by muslim, it was safe to assume it is halal
but there is a case where muslim owned business still take halal certificate. Why?
Jakim halal certificate is approval that the business is halal and complying with the specified legal provisions prescribed by the law of the land.
quote" Proses pensijilan JAKIM melibatkan audit ketat terhadap bahan mentah, pengilangan, dan proses pengedaran, memastikan produk mematuhi piawaian kebersihan dan keselamatan makanan."

so muslim owned street vendor may be halal but could be suspected of been less clean that they should be
So u can go eat at halal certified restaurant if cleanliness is your main concern.