3:19 p.m. Karst: Are there any mysteries about how pathogens become present on vegetable crops? Do you feel the science behind that is fairly well known now, or is there still some mystery about how the pathogens get into the field and crops?
3:20 p.m. Whitaker: I think there are some unknowns. You asked what I am up to lately, I started off with education and we also talked about advocacy with the Food Safety Modernization Act and I would say the third thing that occupies my time is the role I play at the Center for Produce Safety. One of the key research questions is in our request for proposals is that whole idea of transference. How do pathogens become present on fruits or vegetables? How do they survive, or do they survive? Frequently when we test, we will find the presence of pathogen DNA. The more we look for these things we find it. But people aren’t sick. And then suddenly, conditions are changed and suddenly people are sick. So what happens?
Is it genetics, different forms of these pathogens? Is it the environment they are in? Moisture, temperature, expose to sun, nutrient levels? It might be different in one field than in another but suddenly now we have an outbreak, or at least an organism that survives and might be detected. So what are the various pieces or components that cause a perfect storm? Certainly the research we are doing at the Center for Produce Safety and other funding agencies are looking for what those factors are.
We can start to identify some patterns, times of the year when crops appear to be more vulnerable than others. We’re starting to appreciate that some of these organisms are more frequent than what we thought, especially the salmonellas, and seem to be pretty sturdy creatures. We’re not sure that that means from a disease perspective or how they got there. There is research going on now that looks at water as a transfer vehicle. There is research that looks at wind as a transfer vehicle. Of course we are looking at all kind of animals that might have been suspected to be transfer vehicles for some of these organisms.