new dog in house

Question
We have an 8yr old flat-coated retriever who we adopted 3 years ago. He is unbelievably docile and sweet and ALWAYS submissive when he meets new dogs... has always been able to get along with other dogs even when staying at their house for a few days. We just adopted another 8yr old golden retriever mix and he is also very sweet and tame, but twice since bringing him home there has been some aggression around the food. We have provided separate eating places and monitor them during meal times. The problem is my first dog seems terrified of the new dog, won't go past him if he is lying on the floor, etc. Is this normal or is there some way we could help him feel more comfortable? For now we have baby gated half the house for each dog, but they don't seem interested in getting to know each other through the gate. I guess I am wondering if they are doomed to not get along or if there is some hope that they could be friends. If my husband or I is laying with one and call the other over, they will sniff each other and the new dog will lick my old dogs ears... the issues only occurred around food, but my flat coat seems too scared from two small incidents. Any advice would be appreciated. We would hate to have to get rid of the new dog, we adopt older dogs because we want them to get good homes and wouldn't want to be one of the people that gives up on them, but we can't have our baby be afraid for the rest of his life.

Answer
It sounds as though you have brought home "leader", and not another docile "follower".  Your old dog is deferring to the new dog because he's the more confident of the two.  While dogs do need to figure out "where they fit" and there's usually some adjustment, you are correct that your resident dog should not have to feel afraid.  Just don't mistake "subordinate" for afraid.   If these dogs don't seem interested in one another, then why have the second dog?  To be honest, had you asked about adopting a second dog before you did it, I would have probably told you to find a submissive type female a few years younger than your resident dog, and introduce them in a neutral area, off your property.  You really do need to see if dogs like, or are tolerant of, one another, before you bring dog #2 home - if you don't, it's as if your husband just arrived at the door one day with a new wife, and said, "Hope you like her, honey, because she's staying."  If you feel you have to gate the dogs, you are adding to your resident dog's feeling of loss, and adding to your new dog's ability to establish a territory where the old dog is unwelcome.  My advice is to get a behaviorist to come over and view the dogs interacting, and let you know if their behavior is normal or if the new dog is just a bully.
As to the food issue, if you have kids visiting, are planning to be pregnant someday, etc., and the new dog is also food aggressive with humans, that's a prescription for disaster and you may want to reconsider adopting him.  Food aggressive dogs should not be in homes with kids - they need adult supervision and no mistakes.  
Keep in mind that dogs often don't relax into the new environment for weeks, but this guy seems to have taken charge right away, perhaps because your own dog is so docile.  So, if you decide to keep him, you should enroll him in class right away - this dog needs to defer to you, even if he is powerful enough to make your original dog defer to him.  Do not make the mistake, however, of trying to alter the hierarchy between the dogs, as that will just make for continued altercations if the new dog insists on his status.  Most neutered male dogs iron things out ritualistically, and don't do serious damage, so if the new dog put teeth marks in your original dog over the food issue, that's a red flag.