Efficient role of BacTN635 on the safety properties, sensory attributes, and texture profile of raw minced meat beef and chicken breast.

Bacteriocin BacTN635, produced by Lactobacillus plantarum sp. TN635, was purified and characterised in previous work. In this study we report the biotechnological application of this bacteriocin as a biopreservative during storage at 4°C of raw minced meat beef and chicken breast. Overall, the results obtained showed that the addition of the semi-purified BacTN635 at 500 or 1000 AU g(-1) in raw minced meat beef and chicken breast can delay the proliferation of spoilage microorganisms, suppress the growth of the pathogenic microorganism Listeria monocytogenes, improve sensory quality, texture attributes, and extend the shelf-life of these two meat products during refrigerated storage. BacTN635 at 1000 AU g(-1) could extend the shelf-life, and the meat showed good sensory characteristics. Therefore, treatment with semi-purified BacTN635 can be used as a safe method for preservation of raw minced meat beef and chicken breast.

Taxonomy, purification and chemical characterization of four bioactive compounds from new Streptomyces sp. TN256 strain.

A new actinomycete strain designated TN256, producing antimicrobial activity against pathogenic bacteria and fungi, was isolated from a Tunisian Saharan soil. Morphological and chemical studies indicated that strain TN256 belonged to the genus Streptomyces. Analysis of the 16S rDNA sequence of strain TN256 showed a similarity level ranging between 99.79 and 97.8% within Streptomyces microflavus DSM 40331(T) and Streptomyces griseorubiginosus DSM 40469(T) respectively. The comparison of its physiological characteristics showed significant differences with the nearest species. Combined analysis of the 16 S rRNA gene sequences (FN687758), fatty acids profile, and results of physiological and biochemical tests indicated that there were genotypic and phenotypic differentiations of that isolate from other Streptomyces species neighbours. These date strongly suggest that strain TN256 represents a novel species with the type strain Streptomyces TN256 (=CTM50228(T)). Experimental validation by DNA-DNA hybridization would be required for conclusive confirmation. Four active products (1-4) were isolated from the culture broth of Streptomyces TN256 using various separation and purification steps and procedures. 1: N-[2-(1H-indol-3-yl)-2 oxo-ethyl] acetamide 'alkaloid' derivative; 2: di-(2-ethylhexyl) phthalate, a phthalate derivative; 3: 1-Nonadecene and 4: Cyclo (L: -Pro-L: -Tyr) a diketopiperazine 'DKP' derivative. The chemical structure of these four active compounds was established on the basis of spectroscopic studies NMR and by comparing with data from the literature. According to our biological studies, we showed in this work that the pure compounds (1-4) possess antibacterial and antifungal activities.