## 5 _Escherichia coli_ Inactivation by HPP  
Outbreaks of _E. coli_ serotype O157:H7, Shiga-like toxin-producing types, have been associated with a wide range of foods, including ground beef, packaged salads, leafy greens (e.g., lettuce, spinach), sprouts, fresh chopped salads, flour and cake mix, frozen falafel, and raw milk [57]. As this particular strain can survive and grow under very acidic conditions and at low temperatures ([PERSON] et al., 1994, [PERSON] and [PERSON], 1995; [PERSON] and [PERSON], 2001) [58; 59; 60], outbreaks have been registered in high-acid foods as follows: fruit juices (CDC 2022; [PERSON] et al., 1999) [61; 62], apple cider ([PERSON] and [PERSON], 1994) [63], mayonnaise ([PERSON] et al., 1994) [58], mustard and ketchup ([PERSON] and [PERSON], 1997) [64], and yogurt ([PERSON] et al., 1993) [65]. Human foodborne infection symptoms by _E. coli_ O157:H7 include diarrhea (in some cases, bloody diarrhea) and abdominal cramping ([PERSON], 2015) [66]. Laboratory analysis of stool specimens (feces) can be used to diagnose the illness [67]. Table 2 presents the resume of _E. coli_ HPP inactivation studies carried out with milk, non-cured cheese, meat products, coconut water, and acidic fruit beverages ([PERSON] and [PERSON], 1998, [PERSON] et al., 2021, [PERSON] et al., 2019, [PERSON] et al., 2020, [PERSON] et al., 2017, [PERSON] et al., 2022, [PERSON] et al., 1996, [PERSON] et al., 1991, [PERSON] et al., 1999, [PERSON] and [PERSON], 2012, [PERSON] et al., 2001) [47; 48; 51; 53; 68; 69; 70; 71; 72; 73; 74]. Nine studies carried out with O157:H7 strains, ATCC 25922, and cocktails of several strains revealed \(\geq\) 6.0-log reductions in the microorganism in UHT and raw milk, coconut water,  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Strain** & **Food Products** & **pH** & **Pressure (MPa)** & **Temperature (’C)** & **Time (min)** & **Log Reduction** & **Reference** \\ \hline ATCC 25923 & Park slurry & nr & 600 & RT & 10 & 6.0 & [47] \\ \hline ATCC 25923 & UHT milk 2\% fat & nr & 600 & RT & 15 & 4.7 & [48] \\ \hline ATCC 6538 & Cheese slurry & 5.2–5.4 & 600 & RT & 20 & 4.5 & [49] \\ \hline   CECT 976 & Human milk & nr & 594 & RT & 4 & 5.8 & [50] \\ (ATCC 13565) & Poultry meat & nr & 600 & 50 * & 15 & 6.0 & [51] \\ \hline   NCTC 10652 & UHT milk & nr & 600 & RT & 15 & 5.5 & \\ (ATCC 13565) & UHT milk & nr & 500 & RT & 15 & 2.5 & [51] \\ \hline   CECT 534 & Ovine milk & 6.7 & 500 & 50 * & 15 & 3.2 & \\ (NCTC 4163) & \multirow{2}{*}{Raw beef} & \multirow{2}{*}{5.8} & \multirow{2}{*}{500} & \multirow{2}{*}{RT} & \multirow{2}{*}{7} & \multirow{2}{*}{1.7} & \multirow{2}{*}{[53]} \\ \cline{1-1} \cline{5-5} Cocktail of & & & & & & & \\ \cline{1-1} \cline{5-5} 5 strains & & & & & & \\ \hline ATCC 33862 & Human milk & nr & 450 & RT & 15 & \(\geq\)6.8 & [54] \\ \hline  485 & Milk & \multirow{2}{*}{6.7} & \multirow{2}{*}{345} & \multirow{2}{*}{50 *} & \multirow{2}{*}{5} & \multirow{2}{*}{5.5} & \multirow{2}{*}{[55]} \\ \cline{1-1} \cline{5-5} 765 & Milk & & & & & & \\ \cline{1-1} \cline{5-5} 765 & Milk & & & & & & \\ \cline{1-1} \cline{5-5} \cline{5  
ground beef, fresh goat cheese, pork slurry, and several acidic juices (orange, apple, mango, tomato) after HPP treatments in the range of 500-600 MPa for a treatment time of 3 to 15 min, depending on the food and strains. Therefore, the minimum requirement of an inactivation of 5.0 was achieved in most of the studies carried out with this pathogen. The exception were two studies carried out with the specific strain NCTC 12079 in low-acidic foods, poultry meat, and UHT milk, in which only 1.5- and 0.5-log reductions were registered after 600 MPa-15 min treatment, respectively. The same authors, using heat-assisted HPP with an initial food temperature of 50 \({}^{\circ}\)C, could obtain 8.0-log reductions in both poultry meat and milk. Curiously, the same strain and much milder processing conditions (550 MPa-5 min) could achieve >7.0 in orange juice, indicating that it might be easier to inactivate _E. coli_ in high-acidic fruit juices.