## 3 Results  
### Inactivation of E. coli and Selection of Equivalent Processing Conditions for Each Technology  
To identify the best processing conditions required for each technology to achieve a 5-log _E. coli_ reduction, AP samples were processed by CTP, US, PEF and HPP, with Figure 1 presenting the results.  
The initially inoculated _E. coli_ load was 8.05 \(\pm\) 0.50 log CFU/g and its inactivation in the AP samples was observed for all technologies, in varying degrees: it generally increased with the increment in the processing conditions' intensity (except for PEF), which permitted selecting the processing conditions that met the reduction criteria of 5 log units. These results are shown in Figure 1.  
Figure 1: _E. coli_ inactivation by thermal pasteurization (CTP), ultrasound (US), pulsed electric fields (PEF), and high-pressure processing (HPP) to identify the required treatment conditions to achieve a 5-log _E. coli_ load reduction (represented by the dashed red line). Bars with different small letters indicate a significant difference (_p_ < 0.05) between the processing conditions for each technology. Bars with different capital letters indicate a significant difference (_p_ < 0.05) between the selected processing conditions. The bars with squared texture indicate that the detection limit (1.00 log CFU/g) was surpassed.  
The application of CTP (72 \({}^{\circ}\)C for 15 s) led to a decrease of at least 7.01 logarithmic units of _E. coli_, reducing the levels to a point below the detection limit (1.00 log CFU/g). The results demonstrate the impact of the treatment (20 kHz, 2 s on and 2 s off pulses, in a bath at 60 \({}^{\circ}\)C) on different processing times (3, 6, and 12 min). A significantly higher level of inactivation (6.06 \(\pm\) 0.25 log units) was observed for the 12 min treatment, surpassing the 5-log reduction criteria with statistical significance (_p_ < 0.05). The results of PEF-treated samples at different field strength values (7, 10, and 12.5 kV/cm) are presented in Figure 1. Specifically, at a field strength of 10 kV/cm, with treatment conditions of 115 A, 604 kJ/kg, 70 bipolar pulses of 8 us, and at a temperature of 57.2 \({}^{\circ}\)C, a reduction of 5.77 \(\pm\) 0.12 log units was observed. This reduction was significantly higher (_p_ < 0.05) compared to the other field strength values and exceeded the target of at least 5-log-unit inactivation of E. coli. Finally, the results likewise pertain to AP samples that were subjected to HPP treatments at various pressure levels (200, 300, 400, and 500 MPa) for a duration of 1 min. The rise in processing pressure led to a corresponding increase in inactivation levels, as anticipated. Both treatments at 400 and 500 MPa achieved reductions exceeding the 5-log target. The treatment at 500 MPa resulted in a decrease of at least 7.01 log units, bringing the levels below the detection limit. The CTP and HPP processing technologies demonstrated the highest levels of inactivation, surpassing the 5-log-unit reduction threshold, particularly at 500 MPa. Based on these results, the selected processing conditions were 12 min for US, 10 kV/cm of field intensity for PEF and a pressure level of 400 MPa for HPP. This pressure level was selected to provide equivalent inactivation results for the technologies. Given the previously mentioned information, the impacts of these equivalent processing technologies on selected physicochemical properties, antioxidant activities after processing and during cold storage were further evaluated.