Milk rich in conjugated linoleic acid (CLA, 42± 3 mg g−1 fat) was used to evaluate the impact of high-pressure
sterilization (HPS). The pressure, temperature and time needed to reduce 7-log of Bacillus amyloliquefaciens
endospores were determined in the presence of nisin (4–64 mg L−1). In addition, the inactivation of alkaline
phosphatase was evaluated. After HPS treatment, the remaining CLA and formation of hydroperoxides were
monitored during storage up to 60 d at 25 °C. The addition of nisin (≥16 mg L−1) tomilk significantly enhanced
the inactivation of B. amyloliquefaciens (7-log reduction) after treatment at 600MPa, 120 °C and 5 min of holding
time. These conditions were selected to evaluate the impact of HPS on the CLA retention and hydroperoxides
formation. Milk with the addition of nisin and treated with HPS delivered higher retention of CLA and a lower
concentration of hydroperoxides compared with the UHT equivalent process (125 °C/15 s and 135 °C/10 s).
Industrial relevance:High-pressure sterilization is a valuable alternative to produce superior quality milk products
in cases where traditional thermal treatments have failed. This study evaluated the impact of processing
conditions on the conjugated linoleic acid content at conditions where commercial sterilization has been
achieved (7-log reduction of B. amyloliquefaciens). The outcomes of this study are considered as a step further
for the development of high-pressure sterilized milk.