Ultraviolet (UV-C) inactivation of Enterococcus faecium, Salmonella choleraesuis and Salmonella typhimurium in porcine plasma

Abstract

The objective of this study was to assess the effectiveness of an ultraviolet (UV-C, 254 nm) irradiation system on reducing the load of Salmonella typhimurium (S. typhimurium), Salmonella choleraesuis (S. choleraesuis) resistant to streptomycin and Enterococcus faecium (E. faecium) inoculated in sterile porcine plasma and then subjected to different UV-C irradiation doses (750, 1500, 3000, 6000 and 9000 J/L) using a pilot plant UV-C device working under turbulent flow. Results indicated that UV-C treatment induced a viability reduction of 0.38, 1.18, 3.59, 4.72 and 5.06 log10 S. typhimurium when irradiated at 750, 1500, 3000, 6000 and 9000 J/L, respectively. The observed log10 reduction of S. choleraesuis was 1.44, 2.68, 5.55, 7.07 and 7.97 at 750, 1500, 3000, 6000 and 9000 J/L, respectively. The best-fit inactivation for S. choleraesuis was the Weibull distribution curve, while the best-fit curve for S. typhimurium was the Weibull plus tail model, indicating that around 102 cfu/mL resistant S. typhimurium was detected when the liquid plasma was UV-C irradiated at doses up to 9000 J/L. Viability reduction for E. faecium was 0.44, 1.01, 3.70, 5.61 and 6.22 log10 when irradiated at 750, 1500, 3000, 6000 and 9000 J/L, respectively, with no bacterial resistance observed with UV-C doses of 6000 J/L or higher. The biphasic model was the best fit model for the inactivation curve for E. faecium. For the three microorganisms tested, about a 4 log-unit reduction was achieved when the liquid plasma was irradiated at 3000J/L. Overall results demonstrate the usefulness of the UV-C system to inactivate bacteria in liquid plasma before spray-drying. We conclude that the UV-C system can provide an additional biosafety feature that can be incorporated into the manufacturing process for spray-dried animal plasma.

UV-C irradiation is able to inactivate pathogens found in commercially collected porcine plasma as demonstrated by swine bioassay

“…The World Health Organization (WHO) (WHO, 2004) guidelines on viral inactivation and removal procedures intended to assure the viral safety of human blood plasma products establishes that a robust inactivation process should be capable of removing or inactivating at least 4 logs of a wide range of viruses (WHO, 2004). In previous studies, the UV-C irradiation of liquid plasma was able to inactive 4 logs of different bacteria and viruses (Polo et al, 2015;Blázquez et al, 2017Blázquez et al, , 2019 and the present study also demonstrated the lack of transmission of any virus after being UV irradiated at a minimum of 3000 J/L. Therefore, UV-C irradiation complies with the WHO definition of a robust inactivation process.…”

“…Then, the UV-C lamp was switched on and irradiation started. One liter of treated plasma was collected into sterile containers at 3000 and 9000 J/L, as previously described (Blázquez et al, 2017). From the 1-L samples of plasma irradiated at 0 J/L, 3000 J/L and 9000 J/L UV-C, 10 mL were used for intraperitoneal injection in naïve pigs.…”

“…Plasma from blood of healthy pigs is the raw material used to produce spray-dried porcine plasma (SDPP), which is a feed ingredient with functional proteins and bioactive components that is widely used in pig diets due to its beneficial effects on post-weaning performance and survival (Coffey and Cromwell, 2001;Torrallardona, 2010). The manufacturing process of SDPP involves several biosecurity features including collection only from healthy animals at commercial abattoirs under competent authorities inspection, pooled blood which contains antibodies with neutralizing capacity against a variety of pathogens, spray-drying at 80 ºC throughout its substance, and extended storage time at controlled temperature (Blázquez et al, 2017(Blázquez et al, , 2018. However as technology develops, additional redundant safety features should be investigated that follows the recommendations of several international agencies (EMEA, 1996;WHO, 2004).…”

Evaluation of the effectiveness of the SurePure Turbulator ultraviolet-C irradiation equipment on inactivation of different enveloped and non-enveloped viruses inoculated in commercially collected liquid animal plasma

“…The UV-C reactor system SurePure Turbulator used for the study was designed for opaque liquids, manufactured by SurePure Operation AG (Zug, Switzerland) and is described elsewhere [30]. Briefly, the system consists of a reactor with a stainless-steel inlet and outlet chamber with a stainless steel corrugated spiral tube between the chambers.…”

“…In fact, it has been extensively used for disinfection of water, surfaces and food products [23,24]. The inability of UV-C radiation to penetrate opaque liquids can be overcome by introducing adequate turbulence insuring that all of the liquid is exposed to the surface of the UV-C light [25][26][27][28][29][30]. UV-C treatment has been shown to reduce bacterial contamination while not inactivating protein functionality or growth enhancing properties of SDAP [31].…”