The protest outside the branch on Saturday afternoon saw demonstrators picket the store and demand that the supermarket boycott Israeli goods.
During the protest, the manager removed kosher products from the refrigerated section of the shop for a short time.
Colin Appleby posted a picture of the empty shelves in the kosher section on Twitter and said a member of staff had told him "we support Free Gaza".
Appleby tweeted Sainsbury's to ask the supermarket to explain its actions as well as the alleged comment.
The removal of kosher goods also prompted a complaint by Gavin Platman, who posted on the supermarket’s Facebook page: "I presume you are aware that Kosher food is produced in countries other than Israel? You are therefore not making a political statement against Israel but instead are targeting a group based on race – i.e. Jews."
Platman continued that he was "deeply offended" by the move and questioned whether the supermarket had also removed halal food from its shelves.
Other Facebook users also posted to Sainsbury’s page to register their anger. Liat Perry wrote: "Why don't you just put a big sign, reading: NO ENTRANCE TO JEWS AND DOGS, and then we'll know not to waste our time entering your store? That might be blunt but would at least state your real inclinations."
Another Facebook user, Richard Sullivan, posted: "With you now removing kosher food I look forward to you stop stocking halal products. It's only right. Shame on you for being Muslim appeasers."
Sainsbury's issued a statement on Monday in which it emphasised that it was a "non-political organisation".
A spokeswoman for the supermarket said: "We would like to apologise for any inconvenience or offence caused. The decision was taken in one store only to move these chilled products to cold storage elsewhere in that store for a short period on Saturday as a precautionary measure during a demonstration close by.
"They were returned to shelf as soon as was practically possible. Our ambient (store cupboard temperature) kosher range was kept on sale in store throughout. As a non-political organisation, Sainsbury's would never take such a decision on grounds other than ensuring the quality or safety of our products."
Sainsbury's added that there were no circumstances in which it could envisage a boycott of Israeli goods and said it had no evidence that a staff member had made the alleged comment.