They are supposed to be loyal to the company, and stand behind it in times of stress. The company supports others in the community, as well, in the form of taxes, bribes, and workers spending their income in businesses throughout the community. Thus, the company is a political institution with community influence, and the power that goes along with that influence. Political institutions all have several items in common, from group membership to support and influence in the community, as well as representing a large aspect of that community, and the packinghouses all meet these requirements. Finally, the theme of Socialism that the author weaves through the book is representative of politics and political institutions the world over, because its supporters back it because of unrest and dissatisfaction with the way things are, and want them to change. Supporters back political parties and candidates for the same reasons even today, as the Congressional elections of 2006...

The people were dissatisfied with the administration's policies in Iraq and elsewhere, and so, they backed Democratic candidates hoping for change. Now, they say change is not happening fast enough. People will always be dissatisfied with aspects of politics and governing, and people will always demand change and growth - it is simply human nature. Political institutions have to change and grow to please the people, and there will always be some who want to form new parties with new goals and objectives. The Green Party is a good example of that, and so is the growth in Independent registration. In another hundred years, the parties we know may have altered so much we might not recognize them, and another new party, such as the Socialist party of this novel, may have grown and prospered. Politics and institutions change, and that is good for the country and the people.
References

Sinclair, Upton. The Jungle. New York: Doubleday, Page, 1906.