Re: Frozen Spinach & infestation. The only time spinach is at a low level of infestation is when the weather is cool & dry. That is usually in late March (in NJ). After that, it's just too late in the season. This year the NJ Spinach was picked the for the kosher market in May/June.
The question is just how badly infested was the product.
The infested water is recirculated onto the product.
From a practical point of view, it's not a clean product that one should consider using it, regardless of the name on the package.