Soak store-bought mussels in fresh water without salt?

How to Buy, Prepare, Cook & Store Mussels

Don’t soak in water
Don’t immerse them in water – fresh or salt. Freshwater will kill them; if left for too long in static salt water the mussels will use up the oxygen and suffocate. This practice used to be done to purge the mussel of any grit, these days all commercial mussel have been purged and purified in a UV deputation system.

1. Is this wrong? Because websites below all advise soaking in FRESH water.

2. I can’t remember where, but I read that soaking store bought mussels in FRESH water will kill them! They need salt water to survive. Is this correct? Are websites below wrong then?

How To Clean Mussels | Allrecipes

2. Just before cooking, soak your mussels in fresh water for about 20 minutes. As the mussels breathe, they filter water and expel sand. After about 20 minutes, the mussels will have less salt and sand stored inside their shells.

Don’t fear the mussels – Chicago Tribune

Now, many cookbooks and chefs alike advocate soaking mussels in tap water for an hour or so before cooking. The idea is that they’ll take in the clean water and eject any sand or grit that’s hiding inside their shells. Some sources suggest adding flour, cornstarch or cornmeal to the water to encourage the purging. Others suggest these additions will fatten the mussels or whiten their flesh in the process.

Do Mussels and Clams Need to be Soaked Before Cooking?

First, they need to be scrubbed and rinsed in several changes of water to remove whatever dirt is embedded on the shells. Then, they need to be soaked in clean water to expel sand, grit and other impurities that are trapped inside the shells. This step can take anywhere from half an hour to a couple of hours. For best results, change the water several times during soaking.