Where can I find out more about what activities are within the definition of “farm” and what activities are outside that definition?

Table 3 in the proposed produce rule preamble (in section V.A.2.b.i, at 78 FR 3543-4)
provides examples of activities and their classification. For more information, we
encourage you to read section V.A.2.b.i of the proposed produce rule preamble (starting
at 78 FR 3539), and section VIII of the proposed preventive controls rule preamble
(starting at 78 FR 3674), which includes the most detail on this topic.