Go beyond PCR for better aquafeed biosecurity

Formulated aquafeeds offer a biosecure alternative to fresh feeds, yet regulatory standards rely heavily on polymerase chain reaction (PCR) testing to determine biosecurity status. Current PCR methodologies detect targeted pathogen genetic fragments but fail to assess pathogen viability, infectivity, or the inactivating effects of thermal feed manufacturing processes. Major shrimp pathogens, such as White Spot Syndrome Virus (WSSV) and Enterocytozoon hepatopenaei (EHP), become non-infective at temperatures lower than standard extrusion or pelleting conditions, yet heat-inactivated feed may still yield positive PCR results. Additionally, commercial PCR diagnostic kits developed for fresh tissues exhibit variable sensitivity and matrix interference when applied to formulated feeds, leading to false positives, unnecessary batch rejections, trade barriers, and customer mistrust. While in vivo bioassays definitively confirm pathogen viability, they are impractical for routine manufacturing batches. This article advocates establishing an international biosecurity framework with the World Organisation for Animal Health (OIE), national authorities, and industry stakeholders to develop validated standards, feed-specific viability assays, and facility certification schemes that ensure aquafeed biosecurity without relying solely on standard PCR.