Combined Sous-Vide and High Hydrostatic Pressure Treatment of Pork: Is the Order of Application Decisive When Using Minimal Processing Technologies?

Abstract

The aim of using minimal food processing technologies is to preserve the raw material or to achieve a special technological goal with the least possible impact. When several technologies are used together, the intensity of each treatment can be reduced according to Leistner’s hurdle principle. Does the order of application of the treatments result in a detectable difference? This research focuses on the effect of the combination of the sous-vide technology and the high hydrostatic pressure (HHP) treatment. The effect of the pressure level (300 and 600 MPa) and the influence of the treatment order was investigated on pork (longissimus thoracis and lumborum muscles (LTL)). Physico-chemical and microbiological measurements were carried out on day 0 and after 21-day storage at 2 °C and 8 °C. Significant differences were found for both the order of treatment and pressure level in weight loss (p < 0.001), CIELab color parameters a* and b* (p < 0.001), and denaturation enthalpy (p < 0.01). The texture (p < 0.001) and lipid oxidation TBARS values (p < 0.05) were only influenced by the pressure level. In the challenge test, the initial count of 105 CFU/g Listeria monocytogenes dropped below detection limit in all cases. Total aerobic and anaerobic viable numbers were below/near the detection limit in all combined-treated samples on day 0 and showed only slight or more notable growth after 21-day storage at 2 °C and 8 °C, respectively. An additional 300 MPa pressure treatment can increase the safety of sous-vide cooked pork samples while having only a minor effect on physicochemical properties. The 600 MPa pressure treatment results in a stable, albeit not shelf-stable product, but it also affects a considerable number of quality parameters such as color, texture, weight loss, and TBARS values.