The Talmud (Pesachim 23a) tells us that it is forbidden to do business with non-kosher food items (see Shulchan Aruch YD 117:1). The commentators disagree as to whether this prohibition is biblical or rabbinic in nature (see Pischei Tshuva 6 and the Nachlas Tzvi). This is only a prohibition on edible foods. Some say the reason for the prohibition is that a person may come inadvertently come to eat the forbidden food. This prohibition of doing business with treif food is only a prohibition in the case of a biblically prohibited food, which is the case with crab. It is unclear to me what your role in the business is. There is lengthy discussion about whether a person may work for a non-Jew who sells treif. Rav Moshe Feinstein (Igros Moshe Y.D. 1:51) permits one to drive a truck for a company that sells treif. There is also no prohibition if the Jew came into possession of the treif incidentally. Rav Ovadia Yosef (Yabea Omer Y.D. 4:6) extends this leniency to one who is having difficulty finding another job, and is temporarily working for a company that sells treif while trying to find other work. In short, this is a serious issue, biblical in nature according to most. But it is impossible to give specific psak halacha without knowing the particulars both of the person’s life and the job.

The Rambam in his laws of giving to the poor answers this question by outlining eight degrees of preference in giving charity. They are as follows, with #1 being the most preferable and #8 and proceeding in order of more to less preferable:

 

1.       Helping the recipient to become self-supporting through charity, partnership or a loan.

2.       Giving charity while the giver’s and receiver’s identities remain hidden from each other.

3.       Giving while hiding the identity of the giver from the receiver.

4.       Giving while the receiver’s identity is hidden, but the giver’s identity is known to the recipient.

5.       Giving without being asked.

6.       Giving when being asked.

7.       Giving graciously, but less than one should.

8.       Giving reluctantly.

 

In addition, it is important to consider which recipients are preferable. Following are some guidelines:

 

Non-Jews. The Rambam quotes several verses from the Torah at the beginning of his laws on giving to the poor. Not all of these deal exclusively with Jews. The Minchat Chinuch derives from this that giving to non-Jews is also part of the Torah mitzvah of tzedakah, but giving to a Jew in need is preferable and has a greater emphasis in the Torah. In addition, giving charity to non-Jews was encouraged by the Rabbis in order to maintain positive relations with other peoples.

 

Family. It is preferable to help those in need who are closest to the giver. The giver’s family and home-town are preferable. The people of Jerusalem also have a preferred status.

 

Defining poverty. The Talmud leaves the definition of the needs of the recipient very broad. There is a principle of “Dei mechsoro”, meeting the needs of the individual case. This depends on the recipient’s previous and expected life-style.