It is just something else that shouldn’t be there. Or at least shouldn’t be loose in the salad.
Another puzzling thing. Why did the OP take a photo of the salad before it was opened? Was the moth spotted inside the packaging before or after it was opened? Or, was the salad put back in the container (together with a fork) after the moth was discovered for the purpose of the photo. We need to know!
The tub was a large size, about 6" square. It was part of a buffet for my daughters birthday. I had taken a portion out and spotted it on my plate after I'd eaten about half of it!
There is a sequel to the story. I'd left my plate on the table with the monster still on the plate. When we came round to do the washing up, it had disappeared. Thought maybe one of the grandchildren had scraped it into the bin.
This morning I spotted the same insect on the wall, looking very healthy. It must have woken up and escaped from my plate.!
We carefully caught and released it into the garden.