Food safety issues related to eating raw frozen vegetables

While I agree that these types of warnings are conservative and partially CYA, I would suggest that they not be dismissed.

What needs to be understood is that there are other factors involved past the production method. Even if a mfr./producer observes and maintains the highest quality standards in their production facility, they have no control over how the food products are handled after leaving their facilities.

There are many transportation and storage steps between the time products leave a production facility and the time you pick it up from a grocer's shelf. If, in any one of these steps, the food has not been handled properly, the safety has been compromised.

While I would say that the risk may be minimal, it still exists. I am not overly conservative in my own kitchen, but one needs to know that the risk can be real. And just because something hasn't happened yet, it doesn't mean that it can't.

Listeria can be present and does not die when frozen.

http://www.foodsafetynews.com/2016/06/update-producer-others-recall-frozen-vegetables-for-listeria/#.V2ilB9UrLnB

There have been Listeria incidents, as already mentioned, and also Norovirus incidents. Judging how much the presence or absence of a warning on the bag should be used as a reliable guide is very dependent on local/regional labelling and food safety policy.

There is the possibility that your spinach was harvested from a particularly filthy field. If it was harvested anyplace in the "first world" (check the label), I would dismiss the warning. Other than that possibility, what you have there is a warning so overly conservative that it serves to undermine any credibility that the governing body ever had.

In my opinion, that warning should be ignored.

BTW, I'm not of the type to thumb my nose at such things (see: Is smell a bad way of determining whether meat is still good?), at least not here. I am conservative concerning what I will say here, but that warning is ridiculous.