Conceptual models typically contain five to nine verbs, which repre-
sent what activities are the minimum necessary for them to function as
the system described in the root definition. Normally, one or more of the
activities is expanded into a hierarchy of systems by asking how the ac-
tivity is accomplished. The resulting subsystem consists of verbs describ-
ing how one of the activities in the system is carried out. Thus, the “hows”
for an activity in the system become the “whats” of the subsystem. Care-
ful attention to a hierarchy helps to keep activities at similar levels.
State of the Art
Most verbal descriptions and diagrams for fruits and vegetables are
based on a general grouping of all the related businesses, agencies, and
other infrastructures into what is called the industry, the food sector, the
agricultural marketing system, or the postharvest system. Very few ef-
forts have been made to carefully describe the systems involved in terms
of the properties needed for components to be a system. Visual models
provide the opportunity to visualize systems in a hierarchy and to com-
municate other system ideas.
Most studies using SSM have been conducted to improve the orga-
nization that requested the study. Far less experience is available in ap-
plying SSM to situations where there are multiple businesses. Early
efforts (Prussia and Shewfelt, 1993) have shown the value of using SSM
for integrating viewpoints on systems for fruit and vegetable production,
handling, marketing, and consumption. Additional examples are pro-
vided in the following section.
Examples of Visual Models
Most fruits and vegetables reach a final consumer after passing
through several businesses that can be viewed as a chain. For example,
consider a peach eaten by an office worker in New York City after it
was selected from a bulk display and purchased at a local supermarket.
The peach could have been held in a warehouse several days after a two-
day journey by truck from a packinghouse in Georgia where it was grown
on a family farm.
Links in a Chain
The chain in Figure 14.1 represents the businesses needed to deliver
the peach from the tree in Georgia to the office worker in New York