Effects of high hydrostatic pressure processing on embryonation of Toxocara canis eggs

Toxocara canis is a zoonotic nematode parasite that can be transmitted to humans by food or water contaminated with T. canis eggs from infected dog feces. High-pressure processing (HPP) is a useful alternative to thermal treatments to eliminate pathogens from foods. Most of the research on HPP has focused on prokaryotes, but little is known about its effects on eukaryotic organisms. We evaluated the ability of HPP to affect embryonation of T. canis eggs to test the hypothesis that HPP treatment can delay development of T. canis eggs. Efficacy of HPP was determined by using an embryonation assay on T. canis eggs from naturally infected puppies. For each treatment, 2500 T. canis eggs in tap water were placed in sealable plastic bags and subjected to 138-400 megapascals (MPa; 1 MPa=10 atm=147 psi) for 60 s in a commercial HPP unit. We found that treatment with 300 or 400 MPa for 60 s killed 100% of eggs using embryonation as the standard. Treatment with 250, 241, and 207 MPa was less effective and killed 80%, 56%, and 8% of eggs, respectively. Results from this study suggest that HPP may be a useful treatment to protect foods from T. canis contamination.