The stomach is the principal barrier against foodborne pathogens; gastric juices include HCl and pepsin, which have bactericidal activity (Martinsen et al., 2005). Gastric juice usually has a pH of 1 to 2; when food is ingested, the stomach pH increases and decreases gradually (Efentakis and Dressman, 1998). Some foods and beverages can neutralize stomach pH, favoring the survival of foodborne pathogens (Horn and Bhunia, 2018).

The minimum infective dose of Salmonella enterica can be one cell, depending on the strain, host characteristics, and food vehicle (Teunis, 2022). Previously, it was estimated that approximately 104 CFU/g were needed to cause an illness (Blaster and Newman, 1982). This infective dose was, however, modified following reported S. enterica outbreaks related to the ingestion of 10 to 1000 cells in food items with low moisture and high-fat content (Finn et al., 2013; Kapperud et al., 1990).

Several studies have assessed S. enterica behavior under acidic or SGC. However, most of them tested only one or a few strains, often using reference strains (Akbar and Anal, 2015; Aviles et al., 2013; Kim et al., 2014; Mutz et al., 2019; Roering et al., 1999; Yuk and Schneider, 2006). This experimental approach can introduce bias into the results, leading to conclusions that may not be representative of the S. enterica strains present in the spatiotemporal context analyzed. Just a few studies have evaluated the variability of S. enterica strains and serotypes under acidic conditions (in growth media) or mimicking bacterial passage through the stomach (Berk et al., 2005; Guillén et al., 2020a, Guillén et al., 2020b; Lianou and Koutsoumanis, 2013).

The survival capacity of foodborne pathogens under gastric conditions could be related to the genotype and phenotype. The genotype is defined as the genetic profile that characterizes a bacterium, and the phenotype refers to the morphological, physiological, metabolic, and behavioral characteristics that result from the expression of the genotype when exposed to the environment. In the case of S. enterica, most of the studies performed are focused on the phenotype evaluating how the short-term adaptation to stress conditions (acid, osmotic, cold) affects the survival capacity under simulated gastric conditions (SGC) (Melo et al., 2017; Silva et al., 2016; Yuk and Schneider, 2006). A recent S. enterica research performed by Guillén et al. (2022) focused on a different approach, finding that acid stress resistance could be related to virulence but not to antimicrobial resistance.

Recently, there has been a focus on researching the biological variability of foodborne pathogens with the aim of characterizing them and including this variation in quantitative microbial risk assessment (QMRA) (Den Besten et al., 2018; Garre et al., 2022).

For these reasons, this study aimed to characterize the biological variability and assess the impact of intrinsic characteristics of 57 S. enterica strains isolated from food and human cases on their relative survival under SGC. Additionally, evaluate the effect of food matrices (water, mango, tomato, and chicken) in the survival capacity of six selected S. enterica. The data obtained in this study could contribute to the refinement of QMRA models by accounting for the variability of S. enterica strains' behavior through the gastrointestinal tracts depending on the food consumed.