Praise be to Allah
It is not permissible to work in delivering haram food such as that which contains pork or the meat of animals that were not slaughtered in the prescribed manner, or alcohol, because that comes under the heading of helping in sin. The wages earned from doing that are also haraam. Allah, may He be exalted, says (interpretation of the meaning):
“And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty”
It says in Sharh Muntaha al-Iraadaat (2/250): It is not valid to be hired to deliver “dead meat” (from an animal that was not slaughtered in the prescribed manner) and similar things, such as haram blood, to be eaten, for one who is not compelled to eat that; or to deliver alcohol to be drunk, for the reasons mentioned above, and the one who does that is not entitled to any wages for doing it, because haram service cannot be paid for.
But if the improperly-slaughtered meat is being delivered to someone who has no choice but to eat it, then it is valid. End quote.
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said: If someone helps a man to disobey Allah, then he is sinning, because he is helping in sin and transgression. Hence the Prophet (blessings and peace of Allah be upon him) cursed alcohol, the one who presses (the grapes et cetera), the one for whom they are pressed, the one who carries it, the one to whom it is carried, the one who sells it, the one who buys it, the one who pours it, the one who drinks it, and the one consumes its price. Most of those mentioned, such as the one who presses it, the one who carries it and the one who pours it, are helping the drinker to drink it. Hence it is forbidden to sell weapons to those who will use them to fight in unlawful ways, such as fighting the Muslims or infighting among Muslims (fitnah).
End quote from Majmoo‘ al-Fataawa (22/141).
Since when doing the work mentioned it is not clear what type of food is being delivered, then this work is not permissible, because you are living in a non-Muslim country, where the people usually eat pork and drink alcohol.
And Allah knows best.