Shelf-life extension of cooked ham model product by high hydrostatic pressure and natural preservatives

The inactivation of different spoilage organisms and surrogate pathogens in a cooked ham model product by high pressure (HP) treatment (100–700 MPa, 5–40 °C, 10 min) was investigated. A 5 log reduction could be achieved at ≥ 600 MPa at ≥ 25 °C. Subsequently, the shelf-life of packaged sliced product was studied during storage (7 °C) after treatment at 600 MPa (10 °C, 10 min) in combination with caprylic acid and Purasal®. Without HP treatment, a plate count of 6 log CFU/g was reached after 40 days, both in presence and absence of antimicrobials. HP treatment delayed this initiation of spoilage to 59 days in absence of antimicrobials. However, microbial growth was completely suppressed during at least 84 days in the HP treated products containing caprylic acid or Purasal®. HP treatment increased drip loss but had no or little effect on colour and sensorial evaluation by a taste panel. However, the antimicrobials had a negative influence on the flavour and aroma at the concentrations used.Industrial relevanceWith a steadily increasing number of commercial applications being introduced on the market, HP pasteurization is growing out of its infancy. To further support this development, there is a need of integrated studies that translate fundamental scientific findings from simplified laboratory model systems to the complexity and scale of real food products. In this work, we determined HP processing conditions to control spoilage and pathogenic bacteria in a cooked ham model product, and subsequently conducted a large pilot scale experiment comprising a total of 432 individual packages of sliced cooked ham product, in which the microbiological, physicochemical and sensorial quality was evaluated during refrigerated storage after HP treatment. In addition, the usefulness of the natural preservatives caprylic acid and lactate-diacetate as an additional hurdle was also studied. This study is one of the most comprehensive available in the literature to document the shelf-life extension that can be achieved with HP treatment of cooked ham.

Research Highlights
► 5-D reduction of pathogens and spoilage bacteria in cooked ham at ≥ 600 MPa at ≥ 25 °C.
► Combined HP treatment and antimicrobials : shelf-life at least 84 days at 7 °C.
► Increased drip loss after HP treatment, no effect on other quality aspects.