No abstract

Modified atmosphere (MA) packaging plays an important role in improving food quality and safety. By using different gas mixtures and packaging materials the shelf life of fresh produce can significantly be increased. A Gram-negative-staining, rod-shaped, orange-pigmented strain DH-B6T, has been isolated from MA packed raw pork sausage (20% CO2, 80% O2). The strain produced biofilms and showed growth at high CO2 levels of up to 40%. Complete 16S rRNA gene and whole-genome sequences revealed that strain DH-B6T belongs to the genus Chryseobacterium , being closely related to strain Chryseobacterium indologenes DSM 16777T (98.4%), followed by Chryseobacterium gleum NCTC11432T (98.3%) and Chryseobacterium lactis KC1864T (98.2%). Average nucleotide identity value between DH-B6T and C. indologenes DSM 16777T was 81.1% and digital DNA–DNA hybridisation was 24.9%, respectively. The DNA G+C content was 35.51 mol%. Chemotaxonomical analysis revealed the presence of the rare glycine lipid cytolipin, the serine-glycine lipid flavolipin and the sulfonolipid sulfobacin A, as well as phosphatidylethanolamine, monohexosyldiacylglycerol and ornithine lipid, including the hydroxylated forms. Major fatty acids were iC15 : 0 (50.7%) and iC17 : 1 cis 9 (28.7%), followed by iC15 : 0 2-OH (7.0%) and iC17 : 0 3-OH (6.2%). The isolated strain contained MK-6 as the only respiratory quinone and flexirubin-like pigments were detected as the major pigments. Based on the phenotypic, chemotaxonomic and phylogenetic characteristics, the strain DH-B6T (=DSM 110542T=LMG 31915T) represents a novel species of the genus Chryseobacterium , for which the name Chryseobacterium capnotolerans sp. nov. is proposed. Emended descriptions of the genus Chryseobacterium and eight species of this genus based on polar lipid characterisation are also proposed.

The high perishability of fresh meat results in short sales and consumption periods, which can lead to high amounts of food waste, especially when a fixed best-before date is stated. Thus, the aim of this study was the development of a real-time dynamic shelf-life criterion (DSLC) for fresh pork filets based on a multi-model approach combining predictive microbiology and sensory modeling. Therefore, 647 samples of ma-packed pork loin were investigated in isothermal and non-isothermal storage trials. For the identification of the most suitable spoilage predictors, typical meat quality parameters (pH-value, color, texture, and sensory characteristics) as well as microbial contamination (total viable count, Pseudomonas spp., lactic acid bacteria, Brochothrix thermosphacta, Enterobacteriaceae) were analyzed at specific investigation points. Dynamic modeling was conducted using a combination of the modified Gompertz model (microbial data) or a linear approach (sensory data) and the Arrhenius model. Based on these models, a four-point scale grading system for the DSLC was developed to predict the product status and shelf-life as a function of temperature data in the supply chain. The applicability of the DSLC was validated in a pilot study under real chain conditions and showed an accurate real-time prediction of the product status.

The quality loss and shelf life of cherry tomatoes stored in different types of commercially available bio-based packaging trays were analysed and compared with the reference materials, corrugated cardboard and recycled polyethylene terephthalate (rPET). During storage under conditions reflecting points in a regional German supply chain, typical quality parameters were investigated. Surface bacterial counts of the packaging materials were investigated before and after storage, and material parameters were determined for selected packaging.The results showed that groundwood pulp and sugar cane trays showed higher preserving characteristics of tomatoes in comparison with the references. During storage, weight loss was highest for tomatoes stored in polylactic acid (PLA). The highest increase in microbial count with 3.5 log 10 units was observed after 20 days for tomatoes stored in packaging trays of bamboo. The lowest increase with 0.5 log 10 units and 0.6 log 10 units was recorded for tomatoes stored in packaging trays of groundwood pulp and grass paper, respectively. The results of the packaging parameters show the highest (411.0 N) and lowest (79.0 N) tensile strength for cellulose and groundwood pulp. The water absorption capacity ranged from <10 g/m 2 (bamboo, cellulose) up to 211.2 g/m 2 (corrugated cardboard).

Different conveyor belt materials used by the meat and other food industries were compared, regarding their cleanability as bacterial reduction rates in relation to their surface topography. Eleven thermoplastic polymers, four stainless steels, and five aluminized nanostructured surfaces were investigated under laboratory conditions. Cleanings were conducted with water only, and with an alkaline foam detergent. Overall, scanning electron microscopy revealed remarkable differences in the surface topography of the tested surfaces. Water cleaning results showed that nanostructured aluminized surfaces achieved significantly higher cleanability rates compared to the eight thermoplastic surfaces, as well as the glass-bead blasted rough stainless steel. Thermoplastic surfaces showed overall low cleanability rates when cleaned with alkaline detergent, while stainless steel and nanoporous aluminum showed high variations. Overall, nanoporous aluminum showed promising results as it can be used to coat conveyor belts. However, compatibility with cleaning detergent and sensitivity to scratches must be further investigated. Overall, it can be concluded that cleanability is not only influenced by surface roughness, but also by the overall surface finish, scratches, and defects.