The use of pulsed light to inactivate Cryptosporidium parvum oocysts on high-risk commodities (Cilantro, mesclun lettuce, spinach, and tomatoes)

Pulsed light (PL) is an emerging technology with potential applications in food processing. This study investigated the impact of PL treatment on the viability of Cryptosporidium parvum oocysts inoculated onto cilantro, mesclun lettuce, spinach, and tomatoes. A light with pulses at wavelengths of 180–1100 nm, generated at 3 pulses/s with a pulse width of 360 μs was used. Samples were treated for 0, 10, 45, and 90 s at a working distance of 40 cm. Oocyst viability was determined using an HCT-8 cell culture infectivity assay. The maximum log reductions (log genomic copies) achieved on cilantro, mesclun lettuce, spinach, and tomato were 2.4, 4.3, 2.5, and 2.2, respectively. Significant changes in color values (CIE L*, a*, b*) were not observed in leafy greens or herbs; however, wilting was observed in samples treated longer than 10s. Significant change in the b* value for tomato treated for 90 s was observed. Pulsed light can reduce the infectivity of C. parvum oocysts on cilantro, mesclun, lettuce, spinach, and tomato and with further optimization could have potential applications in post-harvest processing of these commodities.