High Hydrostatic Pressure and UV Light Treatment of Produce Contaminated with Eimeria acervulina as a Cyclospora cayetanensis Surrogate

Abstract

The prevalence, size, genome, and life cycle of Eimeria acervulina make this organism a good surrogate for Cyclospora cayetanensis, a protozoan that causes gastroenteritis in humans, including recent outbreaks in the United States and Canada associated with contaminated raspberries and basil. Laboratory studies of C. cayetanensis are difficult because of the lack of readily available oocysts and of infection models and assays. UV radiation and high-hydrostatic-pressure processing (HPP) are both safe technologies with potential for use on fresh produce. Raspberries and basil were inoculated with sporulated E. acervulina oocysts at high (10(6) oocysts) and low (10(4) oocysts) levels, and inoculated and control produce were treated with UV (up to 261 mW/cm2) or HPP (550 MPa at 40 degrees C for 2 min). Oocysts recovered from produce were fed to 3-week-old broiler chickens, which were scored for weight gain, oocyst shedding, and lesions at 6 days postinoculation. Oocysts exhibited enhanced excystation on raspberries but not on basil. Birds fed oocysts from UV-treated raspberries had reduced infection rates, which varied with oocyst inoculum level and UV intensity. Birds fed oocysts from UV-treated raspberries (10(4) oocysts) were asymptomatic but shed oocysts, and birds fed oocysts from UV-treated basil (10(4) oocysts) were asymptomatic and did not shed oocysts. Birds fed oocysts from HPP-treated raspberries and basil were asymptomatic and did not shed oocysts. These results suggest that UV radiation and HPP may be used to reduce the risk for cyclosporiasis infection associated with produce. Both treatments yielded healthy animals; however, HPP was more effective, as indicated by results for produce with higher contamination levels.

Enteric Protozoa in the Developed World: a Public Health Perspective

“…However, significant removal of protozoan cysts or oocysts has been achieved during filtration processes as water passes through a porous medium or membrane, resulting in up to 1.7 to 3.6 log 10 reductions of oocysts, depending on the filter medium used (75). It is therefore recommended that combinations of treatments and multiple-barrier approaches to optimize water treatment through a synergistic effect be employed (107,226,358,364).…”

Update on Cyclospora cayetanensis , a Food-Borne and Waterborne Parasite

“…High hydrostatic pressure (550 MPa at 40°C for 2 min) and UV light (up to 261 mW/cm 2 ) treatments of produce contaminated with E. acervulina as a Cyclospora surrogate were evaluated on experimentally inoculated basil and raspberries (101). Both treatments yielded smaller numbers of animals infected with E. acervulina but did not completely inactivate the oocysts recovered from these food matrices.…”

Cyclospora cayetanensis

“…High-hydrostatic-pressure processing and UV light radiation have been suggested to reduce the risk of cyclosporiasis associated with produce as observed using Eimeria acervulinaas a surrogate for Cyclospora (Kniel et al, 2007).…”