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Background & Aims: High hydrostatic pressure (HHP) processing is a non-thermal method proposed as an alternative to Holder pasteurization (HoP) for the treatment of human milk. HHP preserves numerous milk bioactive components that are degraded by HoP, but no data are available for milk oligosaccharides (HMOs) or the formation of Maillard reaction products, which may be deleterious for preterm newborns., Methods: We evaluated the impact of HHP processing of human milk on 22 HMOs measured by liquid chromatography with fluorescence detection and on furosine, lactuloselysine, carboxymethyllysine (CML) and carboxyethyllysine (CEL) measured by liquid chromatography with tandem mass spectrometric detection (LC-MS/MS), four established indicators of the Maillard reaction. Human raw milk was sterilized by HoP (62.5 °C for 30 min) or processed by HHP (350 MPa at 38 °C)., Results: Neither HHP nor HoP processing affected the concentration of HMOs, but HoP significantly increased furosine, lactuloselysine, CML and CEL levels in milk., Conclusions: Our findings demonstrate that HPP treatment preserves HMOs and avoids formation of Maillard reaction products. Our study confirms and extends previous findings that HHP treatment of human milk provides safe milk, with fewer detrimental effects on the biochemically active milk components than HoP., Competing Interests: Conflict of interest The authors declare no conflict of interest. NS is an employee of Société des Produits Nestlé S.A. Switzerland., (Copyright © 2021 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

In this study, we evaluated the modifications of the protein-related compounds of minced beef treated with high pressure, including refrigeration after treatment. The free amino acid content, protein carbonyls and free thiol groups were assessed. High pressure up to 200 MPa had a significant effect. Above 300 MPa, irreversible structural changes occurred, with an increase in the protein oxidation products and a modification of the amounts of amino acids after 14 days of storage. Protein carbonyls and the free thiols were correlated with the free amino acids. These results showed that protein modifications under pressure result from both conformational and chemical changes, possibly associated with lipid changes under high-pressure treatment., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Campylobacter jejuni is one of the most intriguing human foodborne bacterial pathogen. Its survival throughout the food processing chain and its pathogenesis mechanisms in humans remain enigmatic. Living in the animal guts and particularly in avian intestine as a commensal bacterium, this microorganism is frequently isolated from meat products. Ultra high pressure (HP) is a promising alternative to thermal technology for microbial safety of foodstuffs with less organoleptic and nutritional alterations. Its application could be extended to meat products potentially contaminated by C. jejuni. To evaluate the response of Campylobacter to this technological stress and subsequent recovery at a molecular level, a dynamic 2-DE-based proteomic approach has been implemented. After cultivation, C. jejuni cells were conditioned in a high-pressure chamber and transferred to fresh medium for recovery. The protein abundance dynamics at the proteome scale were analyzed by 2-DE during the cellular process of cell injury and recovery. Monitoring protein abundance through time unraveled the basic metabolisms involved in this cellular process. The significance of the proteome evolution modulated by HP and subsequent recovery is discussed in the context of a specific cellular response to stress and recovery of C. jejuni with 69 spots showing significant changes through time., (Copyright © 2011 Elsevier B.V. All rights reserved.)

High pressure processing is a novel food preservation technology, applied for over 15 years in the food industry to inactivate spoilage and pathogenic microorganisms. Many studies have shown the differential resistance of bacterial cells to high pressure. Listeria monocytogenes is a bacterium able to grow at refrigerated temperature and to survive for a long time in minimally processed foods such as raw smoked fish. The freezing process does not cause significant decline of L. monocytogenes. The phase diagram of water under pressure permits a pressure treatment under subzero temperature, without the disadvantages of freezing for food quality. The aim of this study was to estimate if combined effects of pressure and subzero temperature could increase the destruction of L. monocytogenes in buffer and in smoked salmon. We investigated effects of high pressure processing (100, 150, and 200 MPa) combined with subzero temperatures (-10, -14, and -18 degrees C) and pH (7.0 and 4.5). Results showed that the most effective high-pressure treatment to inactivate L. monocytogenes was 200 MPa, -18 degrees C, and pH 4.5. The relevance of pressure holding time and the synergistic effect of pressure coupled with the subzero temperature to inactivate bacteria are highlighted. Modifications of physical properties (color and texture) were a lightening of color and an increase of toughness, which might be accepted by consumers, since safety is increased.

The effects of pressure treatment (520 MPa for 260 s at 10°C) on lysosomal enzyme activities, Warner-Bratzler (WB) shear values and physico-chemical parameters of post-rigor (day 2) beef (Biceps femoris and Longissimus dorsi muscles) were investigated immediately after treatment and during ageing. Activities of cathepsin D and acid phosphatase in pressurised meat samples were higher than in controls at 2 days post-mortem and throughout storage. This increase in activities was related to the breakdown of the lysosomal membrane and/or to enzyme activation. The WB peak forces were higher for pressurised samples of both muscles at 2 days than in the control and remained higher throughout ageing. The WB shear force deformation curves from pressurised samples showed that the increase in toughness was due to the increase in shear force of the myofibrillar component and not the collagen component. Pressurised muscle led to a significant decrease in sarcomere length and higher cooking loss. Post-rigor application of high pressure induced higher catheptic activity but no conclusive effect on the post-mortem rate of tenderization or tenderness of meat was observed.