It's hit or miss here with new foods and I try not to do that anymore, it always caused tummy upsets and the squirts. I find something that works for all and stick with it. If you persevere usually they will begin to tolerate it.

Occasionally (once or twice) even a new bag of their regular food will do that too.

I would blame that if there are no other symptoms.

As for the flies and bugs, they are going to do that no matter what, I've never associated the squirts with bugs here.