Efficacy of Levulinic Acid-Sodium Dodecyl Sulfate against Encephalitozoon intestinalis, Escherichia coli O157:H7, and Cryptosporidium parvum

Abstract

Foodborne parasites are characterized as being highly resistant to sanitizers used by the food industry. In 2009, a study reported the effectiveness of levulinic acid in combination with sodium dodecyl sulfate (SDS) in killing foodborne bacteria. Because of their innocuous properties, we studied the effects of levulinic acid and SDS at various concentrations appropriate for use in foods, on the viability of Cryptosporidium parvum and Encephalitozoon intestinalis. The viability of Cryptosporidium and E. intestinalis was determined by in vitro cultivation using the HCT-8 and RK-13 cell lines, respectively. Two Escherichia coli O157:H7 isolates were also used in the present study: strain 932 (a human isolate from a 1992 Oregon meat outbreak) and strain E 0018 (isolated from calf feces). Different concentrations and combinations of levulinic acid and SDS were tested for their ability to reduce infectivity of C. parvum oocysts (10(5)), E. intestinalis spores (10(6)), and E. coli O157:H7 (10(7)/ml) when in suspension. Microsporidian spores were treated for 30 and 60 min at 20 ± 2°C. None of the combinations of levulinic acid and SDS were effective at inactivating the spores or oocysts. When Cryptosporidium oocysts were treated with higher concentrations (3% levulinic acid-2% SDS and 2% levulinic acid-1% SDS) for 30, 60, and 120 min, viability was unaffected. E. coli O157:H7, used as a control, was highly sensitive to the various concentrations and exposure times tested. SDS and levulinic acid alone had very limited effect on E. coli O157:H7 viability, but in combination they were highly effective at 30 and 60 min of incubation. In conclusion, Cryptosporidium and microsporidia are not inactivated when treated for various periods of time with 2% levulinic acid-1% SDS or 3% levulinic acid-2% SDS at 20°C, suggesting that this novel sanitizer cannot be used to eliminate parasitic contaminants in foods.

MoWa: A Disinfectant for Hospital Surfaces Contaminated With Methicillin-Resistant Staphylococcus aureus (MRSA) and Other Nosocomial Pathogens

“…Levulinic acid plus SDS-based intervention approaches for reducing contamination with shiga toxin-producing E. coli (STEC) have also proven effective in reducing the bacterial density, although in those studies, the temperature has been a factor for the reduction of bacterial viability with the greatest reduction obtained at temperatures >8°C ( Ortega et al., 2011 ; Zhou et al., 2019 ). This was not a factor in our study as our in vitro test was conducted at 35°C, and the ambient temperature, when assessed using the surface-contaminated model, was ~20°C.…”

“…A similar formulation of LA- and SDS-disinfected bacteria from produce such as pecans ( Beuchat et al., 2012 ; Beuchat et al., 2013 ), cantaloupes ( Webb et al., 2013 ), or those contaminating beef cheek meat ( Schmidt et al., 2014 ) and eradicated bacteria from food slicers ( Chen et al., 2014 ). However, the same LA/SDS solution was ineffective to eradicate parasites, such as Cryptosporidium parvum and Encephalitozoon intestinalis ( Ortega et al., 2011 ). To the best of our knowledge, this LA/SDS solution has not been assessed to disinfect clinical settings contaminated with nosocomial pathogens.…”

Evaluation of Sanitizers for Inactivating Salmonella on In-Shell Pecans and Pecan Nutmeats

“…Treatment of lettuce for 5 min in 0.5% levulinic acid reduced E. coli 0157:H7 by 0.41 CFU/g. The same combination of levulinic acid and SDS reduced planktonic E. coli 0157:H7 by > 7 log CFU/ml within 30 min (41).…”

Gaseous ozone treatment of baby spinach within the existing production chain for inactivation of Escherichia coli O157:H7

“…To minimize the prevalence of foodborne disease and reduce microbial contaminations in food supplies, an effective strategy for application of sanitizers is essential (Tirpanalan et al, 2011). A number of sanitizers based on organic acids (Mendonca et al, 2004;Ortega et al, 2011;Zhao et al, 2009), chlorine (Pirovani et al, 2001;Singh et al, 2002), biocides (Knowles and Roller, 2001;Singh et al, 2002), ozone (Hunt and Marinas, 1999;Khadre et al, 2001;Singh et al, 2002;Vurma et al, 2009) and their combinations (Zhou et al, 2007) have been proposed over the years. Nevertheless, chlorine based liquid sanitizers (in the range 50 -200 ppm free chlorine) still remain the most widely used for disinfection of fresh produce (Luo et al, 2011;Velázquez et al, 2009).…”