when the water is warm, there is higher bacteria count. filter feeders like oysters are susceptible to pick up any bloom. thats why people say don’t eat oysters in months without an R. Most likely what is going on is an oyster producer in another state or country sees an opportunity and is bribing the appropriate officials. My favorite source of oysters is a restaurant in Crystal Beach, TX. It has their own oyster beds in East Bay, and won’t harvest if the water temp is above a certain level.
If I remember correctly(too lazy to google), all oysters contain potentially harmful bacteria. It all depends on the consumers health for protection against bacteria. ie: alcoholism, hepatitis, etc.
I have a funny story about East Bay. My husband and I were trout fishing there back in ‘92 when we saw something in the water. It was a sow and 2 baby pigs swimming around right in the middle of the bay. The babies were exhausted and just about to drown. We caught thm and put them into our boat. When we got back to the small marina where we kept our boat at that time, the owner came out to see what we caught. The Houston newspaper called for a fishing report about that time and i told him about our “catch”. he wrote a nice article Couple Has A Swine Time. Everyone got a nice chuckle out of it.