New formulation for producing salmon pâté with reduced sodium content.

Reducing consumption of salt, specifically sodium, is one of the most effective ways to improve public health. A novel formulation for producing salmon pâté with reduced sodium content was investigated. Salmon pâtés with three different sodium concentrations were evaluated using microbiological, sensory and chemical analyses. Saltwell®, a natural salt containing a mixture of sodium chloride and potassium chloride, was used for partial substitution of sodium chloride (table salt) alone in the formulation. Replacing 80% of the sodium chloride with Saltwell®, resulted in a 22% reduction in sodium, without affecting microbial activity. A trained sensory panel observed minor differences in three of the twelve sensory attributes that were evaluated (coherent texture, saltiness, canned fish flavor). However, these differences were only weakly significant. Saltwell is a viable alternative to sodium chloride to produce seafood products with reduced sodium content without compromising quality and safety.

The cell surface of Lactobacillus reuteri ATCC 55730 highlighted by identification of 126 extracellular proteins from the genome sequence.

Bioinformatical analyses of a draft genome sequence of the commensal bacterium Lactobacillus reuteri ATCC 55730 revealed 126 genes encoding putative extracellular proteins. The function, localization and distribution in bacterial species were predicted. Interestingly, few proteins possessed LPXTG motifs or C-terminal transmembrane anchors. Instead eight proteins were putatively anchored by GW repeats and several secreted proteins were likely to be re-associated to the surface. The majority of the extracellular proteins were widely distributed, i.e., found universally or in gram-positive bacteria, but 24 were only detected in L. reuteri. Further, the number of transporters was lower, while the number of enzyme was higher than in related species.

The early response to acid shock in Lactobacillus reuteri involves the ClpL chaperone and a putative cell wall-altering esterase.

To be able to function as a probiotic, bacteria have to survive the passage through the gastrointestinal tract. We have examined survival and gene expression of Lactobacillus reuteri ATCC 55730 after a sudden shift in environmental acidity to a pH close to the conditions in the human stomach. More than 80% of the L. reuteri cells survived at pH 2.7 for 1 h. A genomewide expression analysis experiment using microarrays displayed 72 differentially expressed genes at this pH. The early response to severe acid shock in L. reuteri differed from long-term acid adaptation to milder acid stress studied in other lactic acid bacteria. The genes induced included the following: clpL, genes putatively involved in alterations of the cell membrane and the cell wall; genes encoding transcriptional regulators; phage genes; and genes of unknown function. Two genes, clpL, encoding an ATPase with chaperone activity, and lr1516, encoding a putative esterase, were selected for mutation analyses. The mutants were significantly more sensitive to acid than the wild type was. Thus, these genes could contribute to the survival of L. reuteri in the gastrointestinal tract.