Assessment of potential probiotic properties and multiple bacteriocin encoding-genes of the technological performing strain Enterococcus faecium MMRA

Food Control

DOI: 10.1016/j.foodcont.2013.09.044

In the present study, Enterococcus faecium MMRA, a safety and technological performing strain, previously isolated from a well-known fermented dairy product of Tunisia, was evaluated for certain properties relevant to probiotic including acid and bile tolerance, gastrointestinal juice resistance and adhesive properties. Acidic pH (2.0-5.0) and bile salt concentrations of 0.3% were used as stress conditions. The adhesive properties were assessed by determination of bacterial hydrophobicity. The strain MMRA showed interesting features such as high tolerance to gastrointestinal tract transit, an extremely high survival rates under stress caused by acidic pHs or bile salts, and a high adhesive potential linked to the elevated percentage of hydrophobicity. Furthermore, the genome of this strain was examined for the occurrence of known enterocin (enterococcal bacteriocins) genes by means of specific PCR assays and this study revealed the genes coding for enterocins A, B, P and X. Although the joint production of these bacteriocins has not been verified, producers of multiple enterocins could have a great technological potential as protective and/or probiotic cultures in the food industry. The results suggested that E.faecium MMRA should be considered as a potential probiotic which meets the criteria to enhance healthy attributes of fermented dairy product besides both of hygienic and sensory aspects.

Production of four potentially probiotic lactic acid bacteria and their evaluation as feed additives for weaned piglets

Animal Feed Science and Technology, (1–2), 2007, 89–107

http://dx.doi.org/10.1016/j.anifeedsci.2006.05.010

The present study was conducted to study the production and evaluation of potentially probiotic additives containing both live lactic acid bacteria (Pediococcus acidilactici NRRL B-5627, Lactococcus lactis subsp. lactis CECT 539, Lactobacillus casei subsp. casei CECT 4043 and Enterococcus faecium CECT 410) and antimicrobial metabolites with could be used as a replacement for antibiotics in weanling pig diets. The gastrointestinal transit tolerance of the four bacteria was determined by exposing washed cell suspensions at 30 °C to acidic conditions (pH 1.0, 2.0, 3.0, 4.0 and 5.0), to a simulated gastric juice (pH 2.0) containing pepsin (3 g/L) and sodium chloride (5 g/L), and to a simulated small intestinal juice (pH 8.0) containing pancreatin (1 g/L) and sodium chloride (5 g/L), mimicking the gastrointestinal environment. These studies showed that the four strains are capable of surviving the passage through the gastrointestinal conditions. Therefore, the production of biomass and antimicrobial products by these bacteria was performed in whey using a fed-batch fermentation technique that provided enhanced productions compared to those obtained in batch fermentations. The obtained fed-batch cultures preserved at −20 °C with skim milk showed a good viability after 3 months of storage. The four cultures exhibited low losses of viability in the piglet feed during their storage at room temperature for 8 days. These results offered the possibility of using the piglet feed as a vehicle to administer the four probiotic bacteria. The effects of the supplementation of separate potentially probiotic cultures and an antibiotic (colistin sulfate) to piglet diets on body weight gain, feed intake, feed efficiency and on the faecal coliform counts of weaned piglets were also studied. Although the best results were obtained in the groups receiving the antibiotic, a significant increase in body weight gain and final body weight was obtained in the groups fed diets supplemented with lactic acid bacteria as compared with the non-treated (controls) groups (P=0.05). The changes in the total coliform population in the control groups over time were not significant (P<0.05), while in the groups fed probiotics and antibiotic, the viable coliform counts significantly dropped at the last sampling (P<0.05). These results suggest that the lactic acid bacteria used in this study could be used as suitable strains for widespread use in the pig industry.