LACtic Bacteria combined with High Pressure for a sustainable stabilization process of meat products – BLAC HP

BLAC HP is made of 6 tasks.The first 3 tasks are research tasks aiming to explore scientific questions of microbiology and food engineering in order to evaluate the potential of the combination of high pressure and biopreservation for the microbiological stabilization of diced hams, chosen as a working model. The effect of the combined processes is studied both at the cellular level, using advanced methods to study bacterial spores under pressure in situ, and at the ecosystem level. To this end, the dynamic response of microbial ecosystems to processes is explored by molecular biology methods. In parallel, the effect of the processes is examined on the nutritional, technological and organoleptic properties of diced ham. Task 4 focuses on the environmental and societal impact of the combination of processes compared to a conventional process. Life cycle analysis with the development of new impact indicators allows an ecodesign approach for the process develoment. The demonstration task 5 will allow pilot scaling and transposition of the process to other products. Finally, task 6 corresponds to the project management and communication actions.

Model sporulating bacteria, as well as their production, conservation and utilization methods, were selected and defined at the beginning of the project. 6 strains characteristic of the refrigerated meat products, of which 3 aerobic species and 3 anaerobic species were selected.
At the same time, 63 strains of lactic acid bacteria supplied by different partners have been screened for their ability to produce active bacteriocins against model sporulating species and their safety (antibiotic susceptibility, non-production of biogenic amines). Three strains of interest were selected to test their baroresistance and a strain of Lactococcus lactis, producing nisin and showing an ability to redevelop after high pressure treatments, was selected for the project.
The effect of HP alone and combined with purified bacteriocins was studied in depth on 3 strains of sporulating bacteria. The results obtained show that the HP sensitizes bacteria to nisin present in the culture medium. The underlying mechanisms are currently under investigation. These results made it possible to select a high pressure treatment scale for the rest of the project.
The study of commercial ham ecosystems revealed a great heterogeneity of the microbial load and diversity of ham. 2 ecosystems were selected for the study of the effect of the process combination.
The protocol for inoculating the ham with the selected protective culture was developed and growth recovery after HP treatment was checked during the storage time at 4 ° C and up to 42 days after treatment. The influence of the combined treatment was tested on the characteristics of texture, water retention capacity, color, olfactory acceptability (triangular test) during storage.

The impact of HP combined with biopreservation by inoculation of L. lactis on spore inactivation and regrowth is curretly investigated. For this purpose, L. lactis / spore co-cultures are carried out in a liquid medium which mimics ham and on diced ham and the growth is followed during storage at 8 ° C.
In addition, the selected ecosystems will be inoculated on diced ham and followed after treatment by the combination of processes selected for the project.
Measurements of protein and lipid oxidation as well as digestibility of the samples that have undergone the combined treatment are in progress.
The pilot scale demonstration project will begin in early 2018.

IAFP symposium on food safety, 29-31 march 2017, Brussels, Belgium. Modugno et al., The Synergistic Effect of High Pressure and Nisin on the Inactivation of Heat-Resistant and Pathogenic Spores in Food Matrices.

Modugno et al., la biopréservation, une stratégie d’avenir pour la conservation des aliments. IAA, novembre-decembre 2015, dossier flore microbiennes d’intérêt.

IFIP- Lettre infos viandes et charcuteries. Bactéries lactiques et hautes pressions pour stabiliser les produits carnées. Novembre 2014

Process Alimentaire, septembre 2015, n°1328 : Produits carnées : un programme pour réduire les nitrites.

HPBB 2016, Toronto, Canada 25/29 july 2016. C. Modugno et al.. High pressure treatment at mild temperature induces irreversible sensitization of bacterial spores to antimicrobial agents.

IAFP 2017, Brussels, Belgium, 29/31 March 2017. Guillou et al. . Combined use of High Pressure Processing and Biopreservation to preserve meat products: Screening, HPP-inactivation and regrowth of three lactic acid bacteria

JSMTV, 21-22 novembre 2016, Paris, France. Pottier, et al. Le procédé par hautes pressions appliqué aux produits carnés.

JSMTV, 21-22 novembre 2016, Paris, France. Rakotondramavo et al. Effet des hautes pressions sur l’oxydation des lipides et des protéines du jambon cuit. (Poster)

12e congrès de la SFM, 22-23 mars. Paris. Ramaroson et al. Sélection de souches de bioprotection combinées aux traitements hautes pressions pour la conservation des dés de jambon.

Congrès sur les bactéries sporulantes pathogènes ou d’intérêt technologique (SFM), Paris, 6-7 juillet 2015. Loison et al., Viscosity mapping of the structures of Bacillus subtilis spores by fluorescence lifetime imaging.

HPBB 2016, Toronto, Canada. Rakotondramavo, et al. Lipid peroxidation of high pressure-treated cooked ham. (Poster)

HPBB 2016, Toronto, Canada. Rakotondramavo et al. High pressure on cooked ham: a way to increase shelf-life while maintaining high standard quality. (Poster)

BLAC HP aims at developing a new strategy for stabilization of refrigerated processed meat products by combining high pressure and biopreservation using lactic acid bacteria. This strategy could become an alternative to the addition of preservatives such as nitrites. The chosen target product is nitrite-reduced diced ham. Thanks to the baroresistance of some lactic acid bacteria, the combination is expected to control both vegetative and spore-forming undesirable flora. It will permit to propose low-energy-produced meat products with high organoleptic quality, with a longer shelf life and with fewer preservatives and bacteriostatic ingredients, particularly nitrites. Our project will not only deeply study the mechanism of microbiological stabilization both at the cell and at the ecosystem levels, it also include the downstream aspects of the development: the resulting nutritional, technological and sensory quality of the product throughout its shelf-life. Furthermore, life cycle analysis will permit to objectively compare the environmental impact of the new process with the traditional process through the creation of new indicators. The program is thus built in a multidisciplinary approach that will provide a solid basis for the understanding and the industrial development of the technology.