Influence of fermentation time, cryoprotectant and neutralization of cell concentrate on freeze-drying survival, storage stability, and acid and bile exposure of Bifidobacterium animalis ssp. lactis cells produced without milk-based ingredients

AIMS

To investigate the stability of Bifidobacterium animalis ssp. lactis VTT E-012010 (=Bb-12) during freeze-drying, storage and acid and bile exposure. The effect of harvesting time and composition and pH of the cryoprotectant on the survival was evaluated. The procedure was performed by using a milk-free culture medium and cryoprotectants to produce cells for nonmilk-based applications.

METHODS AND RESULTS

Bifidobacterial cells were grown in fermenters in general edible medium for 15 or 22 h. The cell mass was freeze-dried either as non-neutralized or neutralized using sucrose, betaine or reconstituted skim milk (control) as cryoprotectants. For stability studies freeze-dried powders were stored at 37, 5 and -20 degrees C for 2-6 months. In addition, acid and bile tolerance of the powders was tested. Sucrose-formulated B. animalis ssp. lactis preparations had an excellent stability during storage at refrigerated and frozen temperatures for 5-6 months. They also had a good survival during storage at 37 degrees C for 2 months as well as during exposure to pH 3 and 1% bile acids. No difference was observed between 15 and 22 h grown cells or between non-neutralized and neutralized cells. Betaine proved to be a poor cryoprotectant compared with sucrose.

CONCLUSIONS

Fermentation time and neutralization of cell concentrate before freeze-drying had no impact on the storage stability and bile and acid tolerance of freeze-dried bifidobacterial cells. The nonmilk-based production protocol using sucrose as a cryoprotectant yielded powdery preparations with excellent stability in adverse conditions (storage at elevated temperatures and during acid and bile exposure).

SIGNIFICANCE AND IMPACT OF THE STUDY

The results indicate that it is feasible to develop nonmilk-based production technologies for probiotic cultures. This provides new possibilities for the development of nondairy-based probiotic products.

Short-term consumption of probiotic-containing cheese and its effect on dental caries risk factors

Cheese is known to contain compounds that reduce the risk of dental caries. The long-term consumption of milk containing Lactobacillus rhamnosus GG, ATCC 53103 (LGG), has been shown to reduce caries risk in children. The aim of the present study was to examine whether short-term consumption of cheese containing LGG and Lactobacillus rhamnosus LC 705 would diminish caries-associated salivary microbial counts in young adults. Altogether, 74 18-35 year-old subjects completed this double-blinded, randomised, placebo-controlled study. During the 3 week intervention, the subjects ate 5 x 15 g cheese per day. Oral examinations were made before and after the study. Stimulated salivary secretion rates, buffer capacity and counts of salivary Streptococcus mutans, yeast and lactobacilli were evaluated before and after the intervention and after a 3 week post-treatment period. The results showed no statistically significant difference between the groups in Streptococcus mutans counts after the intervention, but during the post-treatment period there was a significantly greater reduction in these counts in the intervention group compared to the control group (P=0.05). However, Streptococcus mutans counts decreased in 20% (P=0.01) and yeast counts in 27% (P=0.005) of all the subjects, regardless of the intervention group. Results from logistic regression showed a trend indicating that probiotic intervention might reduce the risk of the highest level of Streptococcus mutans (OR=0.37, 95% CI 0.08-1.75, P=0.21) and salivary yeasts (OR=0.40, 0.09-1.71, P=0.22).

Reduction of linoleic acid inhibition in production of conjugated linoleic acid byPropionibacterium freudenreichiissp.shermanii

A method for the production of conjugated linoleic acid (CLA) from linoleic acid (LA) using growing cultures of Propionibacterium freudenreichii ssp. shermanii JS was developed. The growth inhibitory effect of LA was eliminated by dispersing it in a sufficient concentration of polyoxyethylene sorbitan monooleate detergent. For the whey permeate medium used, the optimum LA:detergent ratio was 1:15 (w/w). As a result, the cultures tolerated at least 1000 µg·mL–1LA, which was converted to CLA with 57%–87% efficiency. The cis-9, trans-11 and trans-9, cis-11 isomers constituted 85%–90% of the CLA produced. The feasibility of the method was demonstrated also in de Man – Rogosa–Sharpe (MRS) broth.Key words: conjugated linoleic acid, linoleic acid, Propionibacterium freudenreichii ssp. shermanii.

Reduction of linoleic acid inhibition in production of conjugated linoleic acid by Propionibacterium freudenreichii ssp. shermanii

A method for the production of conjugated linoleic acid (CLA) from linoleic acid (LA) using growing cultures of Propionibacterium freudenreichii ssp. shermanii JS was developed. The growth inhibitory effect of LA was eliminated by dispersing it in a sufficient concentration of polyoxyethylene sorbitan monooleate detergent. For the whey permeate medium used, the optimum LA:detergent ratio was 1:15 (w/w). As a result, the cultures tolerated at least 1000 microg x mL(-1) LA, which was converted to CLA with 57%-87% efficiency. The cis-9, trans-11 and trans-9, cis-11 isomers constituted 85%-90% of the CLA produced. The feasibility of the method was demonstrated also in de Man Rogosa-Sharpe (MRS) broth.

Clinical benefits of scalp EEG studies in intractable seizure disorders

Intractable seizure disorder is a clinical as well as a diagnostic problem. We evaluated the clinical role of extensive EEGs among patients (n = 64) considered to suffer from intractable paroxysmal neurologic symptoms. By reducing antiepileptic medication, ictal events were recorded in 89% of the cases. From the clinical point of view, intensive EEG-videomonitoring (IVM) was superior to all the other EEG studies. Combined interictal routine EEG (rEEG) and ictal ambulatory EEG (aEEG) findings proved to be surprisingly successful, in some clinical settings equal to IVM. Comprehensive EEG investigations and subsequent treatment in a neurologic ward resulted in proper medication and markedly improved seizure control, confirmed by a prospective clinical follow-up of two years.