Risk Analysis 
Before any new agricultural commodity can 
be allowed into the United States, a pest risk 
analysis (PRA) must be completed. Growth 
in international trade brings with it the pos- 
sibility that harmful nonindigenous organ- 
isms or invasive species could be introduced 
into the United States, resulting in negative 
consequences for producers and consumers. 
PRAs help to identify and quantify the risk a 
specific commodity presents. 
The objective of the PRA process is to pro- 
vide a reasonable estimation of the overall 
risk presented by specific nonindigenous 
organisms or by nonindigenous organisms 
associated with specific pathways or certain 
commodities, such as fruits, vegetables, and 
nursery stock. While a specific agricultural 
commodity may present some risks, the PRA 
also identifies ways to mitigate those risks. 
For example, the United States imports man- 
goes from Mexico even though a PRA identi- 
fied certain regions of that country that are 
inhabited by the Mexican fruit fly. To miti- 
gate the risk of importing Mexican fruit flies 
along with mango shipments, all mangoes 
must be hot-water treated in Mexico to kill 
any fruit-fly larvae. 
In the past, with reference to certain organ- 
isms, agricultural import decisions were 
based on a stated policy of “zero risk.” This 
idea, underpinned by the scientific tools and 
concepts of the time, resulted in very restric- 
tive quarantine measures. This approach was 
taken because there were few alternatives: 
technology was not as advanced as it is today, 
and the mechanisms of pest disease trans- 
mission were not as well understood as they 
are now. Thus, quarantine officials took a 
conservative approach in forbidding the 
entry of many products into the United 
States. 
With the increasing sophistication of 
modern risk analysis, regulators can now 
assemble and analyze pest information in a 
more thorough, consistent, and transparent 
manner. Still, countries must protect against 
foreign pests and diseases. While some agri- 
cultural commodities need only be inspected 
prior to shipment and upon arrival, PRAs 
often recommend some type of treatment to 
protect U.S. agriculture from foreign pests 
and disease. As mentioned earlier, the United 
States allows imports of mangoes from 
Mexico but only after they are hot-water 
dipped to ensure that all fruit-fly larvae are 
killed. Similarly, the United States allows 
imports of clementines from Spain, but first 
they must be cold treated to ward off any 
agricultural pests. 
