Evaluation of Two DNA Template Preparation Methods for Post-Immunomagnetic Separation Detection of Cryptosporidium parvum in Foods and Beverages by PCR

Cryptosporidium parvum oocysts were recovered by immunomagnetic separation from six artificially contaminated foods. Two DNA isolation methods were subsequently evaluated by PCR. The FTA Concen-trator-PS filter provided rapid and reproducible detection, although variability increased at lower inoc-ulum levels (88 % and 15 % detection in high- and low-inoculum-level samples, respectively). Total DNA extraction generated consistent results at all oocyst levels but resulted in longer analysis time (100 % and 59 % detection in high- and low-inoculum-level samples, respectively). Also reflected in this study was that the matrix played an important role in the ability to recover oocysts, as sample turbidity, pH, and PCR inhibitors all influenced detection. Cryptosporidiosis, a severe diarrheal disease in humans, is caused by several Cryptosporidium species, including Crypto-sporidium hominis and Cryptosporidium parvum. As a source for many domestic outbreaks, the prevalence of C. parvum in cattle presents a continual threat to domestic water sources, raw beverages, and fresh produce (7, 9). Epidemiological stud-ies have implicated contaminated raw milk and apple cider i