## Key Factors Determining the Behavior of Pathogens in Dry-Cured Ham after High Pressure Processing  
[PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON],*()  
be marketed under the umbrella of the zero-tolerance policy [3]. Within RTE meat products, dry-cured ham (DCH) is formulated with curing salts as preservatives and subsequently dried to water activity (\(a_{w}\)) below 0.92, which leads to DCH being considered a shelf-stable product, i.e., pathogenic microorganisms such as _Salmonella_ and _L. monocytogenes_ cannot grow [4; 5; 6; 7]. However, a survey conducted on retail products of sliced and pre-packed DCH showed that 50% of the samples had an \(a_{w}\) above 0.92 [8]. Therefore, shelf-stability may not always be assured in terms of complying with food-safety microbiological criteria since pathogens contaminating the product may survive or even grow at a high \(a_{w}\) during storage. In these cases, the application of in-package lethality treatments may be needed to reduce the microbial load before storage. One of the drawbacks faced by RTE meat manufacturers when applying HPP is the enhanced pressure resistance of microorganisms in products with a low \(a_{w}\), especially for products with an \(a_{w}\leq 0.92\) such as DCH [9; 10; 11]. Therefore, the benefits in terms of pathogen-growth restriction provided by the intrinsic characteristics of DCH can turn into a limitation when applying HPP as an in-package lethality treatment aiming to eliminate pathogenic bacteria. Besides the protection of a low \(a_{w}\) on HPP lethality, the effects of other DCH constituents on pressure resistance and particularly the subsequent behavior of surviving cells has scarcely been evaluated. [PERSON] et al. [9; 12] studied the effect of \(a_{w}\), fat, and pressure on the HPP lethality of _Salmonella_ and _L. monocytogenes_ in DCH. The results of these studies showed that the HPP lethality of both pathogens increased with increasing pressure and \(a_{w}\) of DCH. An increase in fat content did not significantly affect the lethality of _Salmonella_ by HPP [12], whereas it led to a protective effect above 700 MPa for _L. monocytogenes_[9]. However, these studies did not report the influence of \(a_{w}\) and fat content of the DCH nor the pressure level on the subsequent behavior of _Salmonella_ and _L. monocytogenes_ during the storage of pressurized DCH.  
Predictive microbiology, also known as quantitative microbial ecology, can be used to characterize the effect of different factors on the behavior of microorganisms in food [13]. In particular, the gamma-concept approach accounts for the individual effects of intrinsic (\(a_{w}\), pH, and lactic acid) and extrinsic (storage temperature) factors and their interaction on the pathogen-growth behavior [14; 15]. The aim of the present study was to continue and expand previous work on the effect of HPP on the lethality (as immediate inactivation) of _L. monocytogenes_ and _Salmonella_ in DCH [9; 12], gaining more knowledge on the impact of the \(a_{w}\) and fat content of DCH and pressure level on the subsequent behavior of _Salmonella_ and _L. monocytogenes_ during the refrigerated storage of DCH after an HPP treatment. To do so, a quantitative study based on the determination of kinetic parameters was used to characterize the behavior of _Salmonella_ and _L. monocytogenes_ in DCH after HPP.