Factual error: In the classroom where Jack argues with Roger next to the chalkboard we can see a poster of the periodic table of the elements. We can see some elements that wouldn't be there in 1977 since they weren't discovered until 1999.
Continuity mistake: In episode 10 Sayid shoots young Ben Linus in the chest, upper left part, just above his heart. It can be seen where the bullet enters the body. In episode 11 when Jin finds the boy and roll him over, the wound and blood is on the right side while the left is clean.
Continuity mistake: When Jack is walking into the medicine cupboard, he has a few small sweat stains on the back of his shirt. The camera cuts to show him turning to a different shelf, and for a split second you can see that his shirt back is now covered in a huge stain, and with large sweat rings under his arms. After he has injected Sayid, his shirt is completely dry again. (00:33:20)
Visible crew/equipment: When Ellie is taking Daniel and the rest to Richard's camp, while they're walking through the jungle, there's a shot of Faraday and then another one of the floor as they walk. In this second shot the shadow of the cameraman, and the camera itself, is very visible.
Continuity mistake: In the replay of Sawyer meeting up with Jin, Jack, Kate, and Hurley, Sawyer takes his glasses off with his left hand. After the scene cuts to Kate and back, Sawyer is now taking his glasses off with his right hand. Not only that, but during that scene in the previous episode, he only took his glasses off with his right hand. (00:05:20)
Continuity mistake: Season 5, episode 8 'LaFleur': When the two Dharma members wake up LaFleur, Sawyer wears a white t-shirt, but when he takes his Dharma overalls his t-shirt turns green.
Continuity mistake: At the end, when we see Ben lighting a candle with a matchstick in the cathedral during the entering of Eloise, he puts out the matchstick so we see that the flame is gone. In the next shot, the flame is back and Ben is doing exactly the same thing, but we see it from another view.
Continuity mistake: Ses. 5, ep. 5, "This Place is Death". When Daniel is telling Charlotte that he has a plan, and explains, "When we were back at the hatch, I talked to Desmond", he places his left hand on top of his right, holding Charlotte's hand between them (seen at bottom of the screen). When the angle changes to a shot above his shoulder, his left hand is suddenly back under Charlotte's head, with no time to move between shots. (00:32:50)
Continuity mistake: "The Variable": When Faraday is on about the variables, he has his jotter in his hands. Camera does a quick cut and it's now on the floor.
Continuity mistake: When Miles and Hurley deliver The Package, the way it's held is constantly changing.
Continuity mistake: When Robert and Danielle banter about what the name of their baby will be, Robert has Danielle's face cupped in one hand, and then suddenly in both hands. (00:06:10)
Continuity mistake: When Miles is sent to deliver "The Package" (i.e. the dead body) to Dr. Chang, after the body is taken out of the van, Miles is seen closing the door to the back of the van. After a return from a flash forward and back to 1977, the door to the back of the van is open again.
Answer: He was eating a peice of an orange with the skin still on.