Prevent Contamination on
the Orchard Floor
The practical realities of modern almond harvest management result in direct contact of nuts with the orchard floor. Whenever almonds come in direct contact with soil or are brought into intimate contact with soil surface materials, the introduction of physical contaminants and some level of microbial contamination is going to happen.
While some level of intermixing of harvested almonds, soil, and organic debris during windrowing is unavoidable, recent surveys have undeniably shown that low levels of pathogens, such as Salmonella, may be present in sporadic locations on the orchard floor surface. Dust aerosols generated during harvest operations can spread these highly localized hot spots within a windrow section and, potentially, across large sections of an orchard block. Implementing practices to reduce dust emissions enables growers to address air quality and food safety concerns simultaneously.
University research has demonstrated that when free moisture combines with contaminated almond hulls or exposed shells, transfer of pathogens from the exterior of the nut to the interior is possible. This passive infiltration is rapidly followed by multiplication of pathogens, such as Salmonella, which grows quickly on the residual nutrients in all parts surrounding the kernel. Additionally, as pathogens grow on the almond hull the potential for the hull to resist environmental stress (such as drying and sunlight) as well as to better tolerate disinfection treatments during processing is increased. The bottom line is that the risk to consumers goes up under these conditions.
Dealing with wildlife in an open farm environment is one of the most difficult challenges growers of all crops have to face in managing food safety risks. All growers face a different set of challenges therefore there are no sure cures or easy and one size fits all methods. While the potential for contamination is undeniable, there is no known specific role of wildlife in past Salmonella outbreaks on almonds. If you have identified some potential problems in your orchard, contact your county Agricultural Commissioner to access CDFA expertise and obtain permits for vector and predator management.
The USDA APHIS Wildlife Services is increasingly involved in issues related to human pathogens in animal populations, especially bird control. The University of California Wildlife, Fish, & Conservation Biology Department maintains a contact resource guide for agriculture wildlife damage and pest abatement.