I am pretty allergic as well. Bur blood worms are good food. I have used Hikari, San Franciso bat and Jehmco ( I am not sure what brand).
I normally buy frozen foods in 1 pount to one kilo blocks/slabs except for blood worms. Those I buy in the blister packs. I switched to Jehmco because they offere the best pricing. I still react to the bloods from the blisters, but not always and never as bad as if I touched them or let "fumes" get to me.
I am also very allergic to something in the nitrogen complex. I believe it is nitrate. In the 1960s I worked in a phtot studio. Among other things I did the developing and printing of B&W film and pictures. Just holding my hand above the trays would set off a bad reaction. I react to bloods in a similar way. I also react to fertilizers when I garden. I have lots of gloves of various kinds......
I only use frozen bloods. I need ones that sink fairy easily as I am feeding a lot of meat eating plecos.