Combination of High-Pressure Treatment at 500 MPa and Biopreservation with a Lactococcus lactis Strain for Lowering the Bacterial Growth during Storage of Diced Cooked Ham with Reduced Nitrite Salt

Abstract

We investigated the combined effects of biopreservation and high-pressure treatment on bacterial communities of diced cooked ham prepared with diminished nitrite salt. First, bacterial communities of four commercial brands of diced cooked ham from local supermarkets were characterized and stored frozen. Second, sterile diced cooked ham, prepared with reduced levels of nitrite, was inoculated with two different microbiota collected from the aforementioned commercial samples together with a nisin-producing Lactococcus lactis protective strain able to recover from a 500 MPa high-pressure treatment. Samples were then treated at 500 MPa for 5 min, and bacterial dynamics were monitored during storage at 8 °C. Depending on samples, the ham microbiota was dominated by different Proteobacteria (Pseudomonas, Serratia, Psychrobacter, or Vibrio) or by Firmicutes (Latilactobacillus and Leuconostoc). Applied alone, none of the treatments stabilized during the growth of the ham microbiota. Nevertheless, the combination of biopreservation and high-pressure treatment was efficient in reducing the growth of Proteobacteria spoilage species. However, this effect was dependent on the nature of the initial microbiota, showing that the use of biopreservation and high-pressure treatment, as an alternative to nitrite reduction for ensuring cooked ham microbial safety, merits attention but still requires improvement.

Contribution of omics to biopreservation: Toward food microbiome engineering

“…While, on the one hand, biopreservation can have an impact on the microbiota, on the other hand, the microbiota can also affect the efficiency of biopreservation. The protective property of a nisin-producing L. lactis strain was tested in combination with high pressure under controlled conditions of microbiota composition in reduced-nitrite diced cooked ham ( Chaillou et al, 2022 ). Sterile diced ham cubes were inoculated with two different microbiota collected from cooked hams, together with the protective L. lactis strain prior to vacuum packaging and high-pressure treatment.…”

“…However, when ham samples were instead inoculated with microbiota dominated by Psychrobacter sp. and Vibrio sp., L. lactis was not competitive and Brochothrix thermosphacta became dominant ( Chaillou et al, 2022 ). Thus, by interacting with the protective strain, food microbiota can act on the efficiency of biopreservation.…”