Browsing by Author "Holliman, D."

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    Effects of high-pressure processing on in vitro infectivity of Encephalitozoon cuniculi
    Jordan, C. N.; Zajac, Anne M.; Holliman, D.; Flick, George J. Jr.; Lindsay, David S. (American Society of Parasitology, 2005-12)
    High-pressure processing (HPP) has been shown to be an effective means of eliminating bacteria and destructive enzymes from a variety of food products. HPP extends the shelf life of products while maintaining the sensory features of food and beverages. In this study, we examined the effects of HPP on the infectivity of Encephalitozoon cuniculi spores in vitro. Spores were exposed to between 140 and 550 MPa for 1 min in a commercial HPP unit. Following treatment, the spores were loaded onto cell culture flasks or were kept for examination by transmission electron microscopy. No effect was observed on the infectivity of spores treated with 140 MPa. Spores treated with between 200 and 275 MPa showed reduction in infectivity. Following treatment of 345 MPa or more, spores were unable to infect host cells. No morphologic changes were observed in pressure-treated spores with transmission electron microscopy.
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    Effects of high-pressure processing on Toxoplasma gondii tissue cysts in ground pork
    Lindsay, David S.; Collins, Marina V.; Holliman, D.; Flick, George J. Jr.; Dubey, Jitender P. (American Society of Parasitology, 2006-02)
    Ingestion of Toxoplasma gondii tissue Cysts can result in severe disease in immunocompromised individuals and pregnant women. Treatment of mean and meat products to eliminate. viable T. gondii tissue cysts would provide a means to protect consumers. In this Study, we examined the effects of high-pressure processing (HPP) on ground pork containing viable tissue Cysts of the VEG strain of T. gondii. Ground pork containing tissue cysts was exposed to 400, 300, 200, 100, or 0 MPa treatment for 30, 60, or 90 sec in a commercial HPP unit. The HPP-treated ground pork Was subjected to acid-pepsin digestion and bioassayed in mice. The results of the mouse bioassay revealed that none of the mice inoculated with tissue cysts exposed to 400 or 300 MPa became infected, whereas all mice inoculated with tissue cysts exposed to 200, 100, or 0 MPa became infected with T. gondii regardless of exposure time. Results indicate that HPP treatment of ground pork with 300 MPa of pressure will render tissue cysts of T. gondii nonviable and make pork safe for human consumption.