When I buy worms I ALWAYS open the tub n look at what is inside. I also smell it... You can smell if they have gotten frozen or to hot.

Be AWARE that some places have Mis-Labeled worms. I found a number of times the tub said Trout Worms but they were NOT red worms nor did they emit a foul slime. They were safe and proper night crawlers/dew worms, Simply labeled wrong.

Always check.