High hydrostatic pressure and time effects on hygienic and physical characteristics of natural casings and condiments used in the processing of cured meat sausage

Effect of Single and Two-Cycles of High Hydrostatic Pressure Treatment on the Safety and Quality of Chicken Burgers

The aim of this study was to evaluate the effect of two cycles of high hydrostatic pressure (HHP) treatment on chicken burgers after storage at refrigeration (4 °C) for 15 days, in comparison with the application of a single cycle of high hydrostatic pressure treatment, as well as compared with non-treated burgers. Samples were treated at 400 and 600 MPa and a single or two cycles were applied. The results showed that mesophilic, psychrotrophic molds, yeast, and coliforms were significantly reduced by HHP treatment (p < 0.05), 600 MPa/1 s (2 cycles) leading to the maximum inactivation. Concerning color parameters, a significant increase in lightness/paleness (L*) and a reduction in redness (a*) and yellowness (b*) (p < 0.05) was observed in samples as 600 MPa were applied. Moreover, 600 MPa/1 s (2 cycles) caused the highest differences in the meat color (ΔE processing) of the chicken burgers. No HHP treatment significantly affected the degree of oxidation of samples (p > 0.05). However, 600 MPa/1 s (2 cycles) samples showed the highest values of TBA RS content after 15 days of storage (p < 0.05). Finally, the appearance, odor, taste, and global perception of cooked burgers were similar in all groups (p < 0.05). Therefore, treatments at 600 MPa produced a significant reduction in microbial counts but modified the color; however, the discoloration effect in the cooked burgers was not noticed by panelists.

Evaluation of Non-Thermal Decontamination Processes to Have the Equivalence of Thermal Process in Raw Ground Chicken

The present study was aimed at examining the antibacterial effects of non-thermal decontamination processes, which are equivalent to thermal treatment, to ensure microbiological safety of raw ground chicken. Escherichia coli or Salmonella were inoculated into 25 g of raw ground chicken samples. The raw ground chicken samples were non-treated or treated with high hydrostatic pressure (HHP) at 500 MPa (1–7 min), light-emitting diode (LED) irradiation at 405 nm wavelength (30–120 min), and heat at 70°C, 90°C (1–60 min), and 121°C (1–15 min). E. coli and Salmonella cell counts were enumerated after treatments. Moreover, the color parameters of treated raw ground chicken were analyzed. HHP treatment reduced E. coli and Salmonella cell counts by more than 5 Log CFU/g and more than 6 Log CFU/g after 7 min and 1 min, respectively; these effects were equivalent to those of thermal treatment. However, LED irradiation reduced Salmonella cell counts by only 0.9 Log CFU/g after 90 min of treatment, and it did not reduce E. coli cell counts for 90 min. Compared with those of the non-treated samples, the ΔE (total color difference) values of the samples treated with HHP were high, whereas the ΔE values of the samples treated with LED irradiation were low (1.93–2.98). These results indicate that despite color change by HHP treatment, HHP treatment at 500 MPa could be used as a non-thermal decontamination process equivalent to thermal treatment.