First of all, you shouldn't have to worry about bacteria introduction to your tanks if you rinse the brine shrimp before you add them to your tank. The most likely intro point would be just after hatching when the hatching water can contain the bad bacteria.
If you buy the brine from the LFS
, be sure to feed them first before you give them to your fish. (phyto, cryopaste, spirulina, selco/selcon)
For those of you who believe that the brine shrimp are devoid of nutrition, research the mariculture industry that produces fish and shrimp for us to eat.
The mariculture industry make brine shrimp a large part of the diet they feed their production, utilizing both nauplii (newborn) and adult brine shrimp. By gut loading the brine shrimp you get the best of both stages as the adults are high in protein but low in huffas, whereas the nauplii are lower in protein but have high huffa content in the egg sack. See this report for the United Nations edited by Patrick Lavens and Patrick Sorgeloos,
Laboratory of Aquaculture and Artemia Reference Center
University of Ghent
Scroll down to section 4.4 on nutrition.
My best guess as to how the misconception on brine nutrition began is the fact that the frozen products are calculated on the total mass of the package including moisture of the brine and the packing fluids, whereas a flake food would have little moisture to affect the percentages.
If you add the flake food to the tank, and the fish eats it wet, then the percentages then would differ from packaged conditions.
Conversely, if you dry out the frozen brine shrimp, then the levels look great again. To be fair, compare all foods in similar conditions, wet or dry.
Mysids have been reported as having much better nutrition, but the main feed for raising mysids is brine shrimp nauplii.
Raising brine shrimp to adult is labour intensive and sometimes fraught with frustration but I do it because here in Southwestern Ontario, I have no supply of live adult brine shrimp available to me.
For those of you who do have access to these adult shrimp, the only down side of purchasing them is the fact that very few stores would be feeding them properly to keep their nutrition levels up, so you need to feed them for at least an hour before feeding them to your fish.
If you didn't see the link posted earlier that goes to my brine page, here it is again.
RAISING BRINE SHRIMP