All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, we should look into the reason behind that gift and the food which was sent to you as a present, if the reason was to influence your husband and make him promote that employee, then it is not permissible to accept it as it is a bribe. But if you used to exchange presents before that, or that your husband does not know him at the first place, but his promotion was done routinely as you mentioned, then these presents are permissible as they have nothing to do with the promotion of that employee.
In fact, there are some gifts that are permissible and even encouraged in Sharee’ah as they create affection and friendship between the Muslims; the Prophet said in this regard: “Give gifts to one another, you will love one another.” [Maalik]
This kind of gift is desirable as long as it does not lead to establishing what is false or abolishing what is a true, or that its purpose is not to influence the person to whom it is given due to his position at work hoping to benefit from his favoritism.
In any case, if you are in doubt about the matter and you fear that the reason behind the gift was hoping to influence your husband in his decision to promote the employees, then it is better not to accept it. The Prophet said: “Consult your heart: righteousness is that about which the soul feels tranquil and the heart feels tranquil, and the sin is what wavers in the soul and wavers to and fro in the heart, even if the people issue a Fatwa to you again and again (in its favor).” [Ahmad]
Allaah Knows best.