My last experience of eating on EasyJet was my last.
We sat in the front row on the left and could see the FAs preparing and plating up. One FA was eating his own meal at the same time, putting his fingers up to his mouth and licking them, and then going straight on to deal with passengers' food without washing his hands. My wife complained loudly about this, and he eventually stopped. Thereafter, all the FAs made great play of publicly sanitizing their hands with antiseptic wipes, but it was too late. I had extreme diarrhoea that night. Since the EasyJet food was the only food I had consumed over the previous day and a half, the connection was obvious.
I highly doubt that a FA licking his fingers will give people diarrhoea.