Salmonella response to physical interventions employed in red meat processing facilities

Abstract

Salmonella is a foodborne bacterial pathogen associated with red meat production worldwide. Survival of, and cross contamination with, this pathogen at any stage from the farm to the processing facility may result in human disease. Cattle, goat and sheep are common animal reservoirs of Salmonella. Various interventions to control the spread of this pathogen during red meat processing have been applied. Physical interventions, such as chilling, thermal treatments, ionizing radiation, ultraviolet radiation, as well as novel interventions such as high pressure treatment and ultrasound, have been used with varying success to reduce Salmonella during processing. This review examines the use of physical interventions to control Salmonella during processing and the stress response of Salmonella towards these interventions. Most existing studies do not provide a very strong insight into the molecular mechanisms of survival of Salmonella after exposure to these physical interventions. Attachment of Salmonella onto red meat species may be strain specific and the genetic profile of these strains may contribute to the survival of Salmonella during red meat processing. Bacterial sigma factors which may act as DNA repair proteins may induce the expression of virulence genes. Salmonella may develop a tolerance mechanism to these physical interventions by enhancing the expression of genes which may provide protection to cells during processing. Developing effective approaches for reduction and elimination of this pathogen on red meat still remains a challenge due to a lack of understanding of the stress response of different serovars of Salmonella. Genome wide stress responses and validation of the gene expression of Salmonella transcriptomes and proteomes need to be intensified to determine phenotypic and genotypic profiles of Salmonella on different red meat species under these different stressors.