Willie Macleod, executive director of the British Hospitality Association, said many retailers "relied on daily deliveries" from Blochairn.
Firefighters began tackling the blaze in the early hours of Thursday.
Mr Macleod said suppliers at the market were sure to be "resilient" but that businesses would be impacted.
City Property, which owns the site, said it was trying to establish alternative arrangements so that normal business could resume as soon as possible.
Mr Macleod told the BBC: "The impact on the market - short and medium-term - is not yet clear, it's unlikely that normal operations will be possible for the immediate or foreseeable future.
"Any disruption to supplies of fresh produce will have an impact on hospitality businesses and caterers, as well as retailers - many of whom rely on daily deliveries."
Mr Macleod said that in the immediate term, menus were likely to be adjusted and, in some cases, fresh produce would be substituted by frozen items.
He added: "I'm sure that the wholesale suppliers which operate out of Blochairn will be resilient and adaptable and will already be looking at alternative arrangements for their customers - possibly using alternative markets such as Edinburgh or Newcastle in the interim.
"Hospitality businesses will look for alternative, short-term sources of supply where they can.
"Many larger chains and  branded outlets operating in the west of Scotland will have national or regional procurement arrangements in place - these will not necessarily be reliant on Blochairn, so the impact in these cases is unlikely to be so severe."
Donald Neilson, director of seafood company John Vallance, had been processing orders and loading vans when the fire broke out.
"It was a pretty quick evacuation and most of our stock was left lying," he said.
"We supply from the market to other wholesalers, restaurants, hotels, fish and chip shops and places like that.
"The west of Scotland and central Scotland - all the restaurants and hotels - will have to go without orders today."
Mr Neilson said he was hopeful the fire had been stopped before it got the the fish market area.
"Hopefully we'll get back into the markets as soon as possible because all our  computers and office stuff is there.
"We also want to check our chills, our freezers and our tanks are ok."
In the meantime, he said they had secured temporary warehouse space and hoped to provide a service from there.
Jim McGhee, who owns Castle Douglas fruit and veg shop Mitchell's, was also there when the fire broke out.
"We have a wholesale fruit business with a retail outlet and we go to the market two to three times a week," he said.
"I had just got my lorry loaded up luckily - there were a couple of things I didn't get because the police asked us all to leave the area.
"There is a bit of the market that hasn't been touched by the fire so I would think we will still be OK next week to get stuff.
"The top end of the market has escaped the fire it is just the bottom end."
He said a couple of the fruit and vegetable businesses been affected, and the flower market had been burned.
"I managed to get a load this morning, I was up there quite early and I was just about fully loaded when the fire broke out, so I am OK for today and the weekend," he added.
"We are a wee bit worried about Monday but hopefully there should be enough businesses open to get us what we need."
A huge fire at a Glasgow fruit and vegetable market will hit local restaurants, flower shops and cafes, an industry chief has predicted.