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 relevance: With 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.

No abstract

No abstract

This study evaluates effect of tumbling time and cooking temperature on cooking rate, cooking loss (CL), colour, water activity and water-holding capacity of cooked restructured ham rolls. In experiment were investigated three tumbling times (2, 4 and 6 h) at constant temperature (+4°C) and three cooking temperatures (76, 86 and 96°C). It was observed that CL decreased (P < 0.01) from 5.41% to 3.22% with tumbling time (2 h vs. 6 h) but increased (P < 0.01) from 2.35% to 7.25% along with cooking temperature (76°C vs. 96°C). In contrast, pH value increased (P < 0.01) from 6.18 to 6.24 with tumbling time (2 h vs. 6 h) but decreased (P < 0.01) from 6.22 to 6.17 along with cooking temperature (76°C vs. 96°C). In addition, high temperature had higher efficiency for thermal lethality than low temperature (F 0 values were 19 and 92 min at 96 and 76°C, respectively). Intermediate tumbling (4 h) and cooking (86°C) could be preferential.

Food producers apply modern processing techniques and use a variety of preservative additives to guarantee safe food and a longer shelflife. Regrettably many of these impact the sensory characteristics of the foodstuffs, such as colour, texture, and flavour, which can result in low consumer acceptance. Additionally, strategies used to reduce growth of spoilage and pathogenic bacteria are not selective enough and may inactivate also desired microbiota. Food is usually overdosed with antimicrobials that are supplemented 'just in case.' Consequently, food producers are searching for natural preservation methods that are not harmful to humans. Nature offers a wide spectrum of biologically active (phyto) chemicals that can be used as potential natural preservatives. Compounds with bacterial growth-limiting properties are detected in all parts of plants, including their leaves, flowers, fruits, roots, etc. These are mostly acids, alcohols, medium and long-chain organic acids, terpenic compounds, and their derivatives. This study focused on the effectiveness of plant extracts, i.e., synergism between terpenoids and medium chain fatty acids in cured cooked meat. Bacterial strains that were tested include typical members of the spoilage microflora in vacuum (Lactobacillus curvatus) and MA-packed meats (Brochothrix thermosphacta). These were isolated and identified in a separate study. L. curvatus was observed to be very resistant against either terpenoids or fatty acids when used separately, whereas its growth was strongly inhibited when both chemicals were combined. Growth of B. thermosphacta was significantly inhibited when antimicrobial compounds were solely applied, whereas a blend of terpenoids and fatty acids showed an almost bactericidal effect.