Susceptibility of Pathogenic Nontyphoidal Salmonella Serovars and Avirulent Salmonella LT2 to Elevated Hydrostatic Pressure and CitricidalTM

Abstract

Nontyphoidal Salmonella enterica serovars are the leading cause of foodborne hospitalization and death episodes in the United States. In a typical year, it is estimated that >1 million Americans experience illness due to foodborne nontyphoidal Salmonellosis. While the private industry and manufacturing rely heavily on results of validations studies for inactivation and decontamination of this prevalent and opportunistic pathogen of public health concern, availability of such studies conducted in realistic environments of manufacturing and processing is limited due to pathogenic nature of the organism. The current study investigated effects of elevated hydrostatic pressure and a bioactive product from grapefruit seed extract (CitricidalTM) for elimination of nontyphoidal Salmonella serovars. Additionally, sensitivity of an avirulent strain of the bacterium (Salmonella LT2) investigated relative to the pathogenic Salmonella serovars. Our results show that the avirulent strain utilized in the current study, has similar sensitivity to the treatments compared to nontyphoidal pathogenic Salmonella serovars. Thus, this non-pathogenic strain could be used interchangeably for public health microbiology hurdle validation studies as a surrogate for pathogenic Salmonella serovars. Additionally, we observed >5 log reduction of the pathogen (i.e. > 99.999%) due to treatments with elevated hydrostatic pressure at 500 MPa and at 300 MPa with presence of CitricidalTM. Our result additionally exhibits that combination of mild hydrostatic pressure and bioactive compounds such as CitricidalTM could be utilized to ensure safe and efficacious elimination of this prevalent pathogen of public health concern from common commodities.

Practical Preventive Considerations for Reducing the Public Health Burden of Poultry-Related Salmonellosis

“…During the 1990s, S. Enteritidis outnumbered other serovars in poultry environments, and foodborne illness associated with it was noticed in many countries [62]. In recent years, Salmonella serovars like Heidelberg, Minnesota, Montevideo, Tennessee, and Kentucky continued to rise within poultry food chains and food products at a global scale [8,63,64]. The use of phages as an alternative to antibiotics has other co-benefits as well.…”

“…Similarly, around 27 million global cases of salmonellosis are estimated to be associated with typhoidal Salmonella serovars [5]. Various typhoidal and non-typhoidal Salmonella serovars are capable of forming complex biofilms on biotic and abiotic surfaces, further complicating the challenges associated with the control of this prevalent and opportunistic pathogen [6][7][8]. Under the landscape of a changing climate, the public health challenges associated with Salmonella serovars, and with antibiotic resistance are expected to be further augmented in the future [9,10].…”

Public Health Importance of Preventive Measures for Salmonella Tennessee and Salmonella Typhimurium Strain LT2 Biofilms

“…Salmonella enterica subspecies enterica serovar Typhimurium, strain designation LT2 (Salmonella LT2), was included in the current study as a surrogate for pathogenic Salmonellae. The strain was available in the Public Health Microbiology Foundation SM strains library and had been shown to have comparable sensitivity to heat, antimicrobials, and non-thermal processing when compared to a set of a five-strain diverse mixture of nontyphoidal Salmonella serovars (ATCC ® 13076 ™ , 8387 ™ , 6962 ™ , 9270 ™ , 14028 ™ ) in the food environment [24]. These two strains were stored, activated, sub-cultured, and purified using the methods detailed in our recent open-access studies [12,25,26].…”