Survival Of Probiotic Bacteria Research Articles

Growth and survival of probiotic bacteria in reconstituted whey

Considerant l'interet nutritionnel du lactoserum, cette etude a ete entreprise pour y definir la croissance et la survie de bacteries probiotiques et l'influence de l'addition d'un prebiotique, l'inuline, dans le but de produire une boisson nutritive. Pour obtenir des conditions experimentales identiques, la fermentation a ete realisee sur du lactoserum reconstitue a environ 6 % de matiere seche, qui a ete ensuite pasteurise puis inocule avec 3 types de cultures probiotiques commerciales : La-5, Lb-12 et Lc-01. Les echantillons ont ete fermentes a 37 °C pendant 24 h et evalues sensoriellement. Les boissons obtenant les meilleurs scores (apres 18 h de fermentation) ont ete conservees au froid pour determiner leur stabilite. Apres 28 jours de stockage au froid, les denombrements bacteriens etaient superieurs a 10 7 cfu.mL -1 et aucun echantillon ne presentait d'alteration. L'addition d'inuline avait un effet pratiquement negligeable sur les denombrements bacteriens au cours de la fermentation et de la conservation au froid.

Survival of probiotic bacteria in a whey cheese vector submitted to environmental conditions prevailing in the gastrointestinal tract

Abstract Various foods may be used to deliver probiotic bacteria into the gastrointestinal tract; one such example is Requeijao, a Portuguese whey cheese. Survival and stability of Bifidobacterium animalis strains BLC-1, Bb-12, and Bo, Lactobacillus acidophilus strains LAC-1 and Ki, L. paracasei ssp. paracasei strain LCS-1 and L. brevis strain LMG 6906 inoculated into Requeijao, when exposed to simulated gastrointestinal tract conditions, were assessed. Homogenates of inoculated whey cheese in 0.85% (w/v) sterile saline water were exposed to a solution of hydrochloric acid (pH 2.5–3.0) and pepsin (1000 units mL–1) at 37 °C, and then to 0.3% (w/v) bile salts after 60 or 120 min of acid exposure. All bacterial strains retained their initial viable cell numbers. Bifidobacterium animalis strains Bb-12 and Bo, and L. brevis strain LMG 6906 exhibited the highest viable cell numbers when exposed to bile salts, whereas the other strains had variable death rates.

A Review of Oxygen Toxicity in Probiotic Yogurts: Influence on the Survival of Probiotic Bacteria and Protective Techniques.

Oxygen toxicity is considered a significant factor influencing the viability of probiotic bacteria such as Lactobacillus and Bifidobacterium spp. in yogurts. This review assesses the involvement of oxygen during the manufacture of yogurt and its diffusion into the final product. The oxygen sensitivity of Lactobacillus acidophilus and Bifidobacterium spp. is discussed. The impact of dissolved oxygen of the product on the survival of these probiotic bacteria is highlighted. Additionally, microbiological, chemical, and packaging techniques recommended to protect probiotic bacteria from oxygen toxicity in dairy products are reviewed.

Effect of packaging materials and dissolved oxygen on the survival of probiotic bacteria in yoghurt

SummaryThe effects of packaging materials on the dissolved oxygen and the survival of the probiotic bacteria in yoghurt were studied. Oxygen adapted and non‐oxygen adapted strains of Lactobacillus acidophilus and Bifidobacterium spp. were incorporated in yoghurts, which were packaged in oxygen permeable high‐impact polystyrene (HIPS), oxygen‐barrier material (NupakTM) and NupakTM with an oxygen scavenging film (Zero2TM). During storage the dissolved oxygen increased steadily in HIPS packaged yoghurt whereas it remained low in yoghurts packaged in NupakTM and Zero2TM. In all yoghurts, no significant decreases were observed in the viability of either oxygen adapted or non‐oxygen adapted cells of L. acidophilus and Bifidobacterium spp. Thus, although the dissolved oxygen in yoghurt can be influenced by the type of packaging material, it may not affect the survival of probiotic bacteria in yoghurts.

Probiotic cell counts and acidification in fermented milks supplemented with milk protein hydrolysates

Abstract In the present work, the effect of milk protein hydrolysates on probiotic cell counts and acidification in fermented milks was studied. Two strains of probiotic bacteria, Lactobacillus acidophilus LA-5 and Lactobacillus rhamnosus LR-35, were used in mixed culture with Streptococcus thermophilus ST-7. The effect of three casein hydrolysates and three whey protein hydrolysates were investigated by adding them to milk at a concentration ranging from 0.25 to 4 g L −1 . Addition of hydrolysate enhanced the growth of S. thermophilus and acidification, thus reducing the fermentation time, and growth of probiotic bacteria. On the other hand, survival of probiotic bacteria was improved when milk was added with hydrolysate. As a consequence, the addition of hydrolysate had a differential action on probiotic cell counts in fermented milks after storage, depending on the balance between its negative effect on growth of probiotic bacteria and its positive effect on the survival of probiotic bacteria.

Survival of dairy-associated yeasts in yoghurt and yoghurt-related products

The poor survival of probiotic bacteria added to yoghurts is mainly attributed to the low pH of the product environment. Since yeasts have the ability to metabolize organic acids, resulting in a decrease in acidity, the inclusion of yeasts as part of the normal microflora, in association with probiotic bacteria has been suggested with the intention to assure better survival of the probiotic organisms in bio-yoghurt. Furthermore, a commensalistic association between yeasts and lactic acid bacteria exists. In order to understand the potential impact of yeast on probiotic bacteria, it was firstly important to assess the ability of yeast isolates to grow and survive in yoghurt. Accordingly, four dairy-associated yeasts, Debaryomyces hansenii, Kluyveromyces marxianus, Yarrowia lipolytica and Issatchenkia orientalis, associated commonly with yoghurt were isolated and inoculated subsequently into yoghurt and related dairy products during processing. The survival and growth of the yeasts were monitored over a 4-week storage period, the normal time accepted as the shelf-life of yoghurts. pH, sugar utilization and the production of organic acids were determined on a regular basis during the shelf-life to evaluate the possible contribution of the yeasts towards the products. The yeast species were able to survive in bio-yoghurt reaching maximum counts exceeding 10 7 cfu g −1. Despite the inability of some species to utilize lactose, the yeast species utilized available organic acids, galactose and glucose derived from bacterial metabolism of the milk lactose, as well as possible free fatty acids or free amino acids present in the dairy products. Excessive gas and ethanol production initiated by some yeast species proved, however, to be major constraints.

The effect of yoghurt culture on the survival of probiotic bacteria in oat-based, non-dairy products

The survival of the probiotic strains Lactobacillus reuteri ATCC 55730, Lactobacillus acidophilus DSM 20079 and Bifidobacterium bifidum DSM 20456, all of human origin, were investigated in three different oat-based, non-dairy products (Adavena M40, MG20 and G40). The products were fermented by the three strains with and without the presence of a commercial yoghurt culture (V2). Samples were stored at 6 °C up to 30 days. In general, the oat-based products were shown to be a suitable support for these intestinal bacteria. L. reuteri ATCC 55730 had the highest viability in all of the products investigated. After 30 days the cell viability of L. reuteri ATCC 55730 was 10 8 CFU ml −1 in all three oat-based products. Lower viability was seen when the strains were grown in the presence of the yoghurt culture compared to when they were grown as pure cultures. These products also exhibited a lower pH value in comparison to products fermented with the pure cultures. The utilisation of the main fermentable carbohydrates in the products varied across the bacterial strains. A decrease in β-glucan content was seen for the products fermented by the B. bifidum DSM 20456 strain. This work shows that these oat-bases with different mono- and disaccharide composition can be used to support the growth of human intestinal bacteria and also maintain high cell viability during cold storage.

Environmental adaptation of probiotic lactobacilli towards improvement of performance during spray drying

The potential of environmental adaptation as a survival mechanism enabling a human-derived probiotic Lactobacillus strain to withstand heat stress and spray drying was investigated. Heat-adapted (52°C for 15 min) L. paracasei NFBC 338 exhibited 300- and 700-fold greater thermotolerance (survival at a lethal temperature of 60°C) compared with controls, in MRS and reconstituted skim milk (RSM), respectively. The level of thermal protection in RSM by pre-adaptation in hydrogen peroxide (0.003 m), salt (0.3 m NaCl) and bile salts (0.1% w/v) was also examined. Although not as efficient as the homologous stress, the levels of cross protection were in the order heat>salt>hydrogen peroxide>bile. Viability of the heat-adapted L. paracasei NFBC 338 in RSM was enhanced 18-fold during spray drying at outlet temperatures of 95–105°C, while salt-adapted cultures exhibited 16-fold greater viability than controls. These results highlight the potential of preconditioning treatments for maximizing survival of probiotic bacteria during development of probiotic functional foods. The cross protection afforded by salt against thermal stress may indicate that certain common protective mechanisms are induced by both heat and salt stress.

Application of RBGR—a simple way for screening of oxygen tolerance in probiotic bacteria

Oxygen toxicity is a major problem in the survival of probiotic bacteria in dairy foods. High levels of oxygen in the product are detrimental to the viability of these predominantly anaerobic bacteria. Screening probiotic bacteria for oxygen tolerance before their incorporation could ensure high cell counts in food products during storage. Reported techniques have focused only on qualitative estimations of oxygen tolerance in probiotic bacteria. To characterize the oxygen tolerance of a large number of organisms, a quantitative measurement is essential. For the first time, the oxygen tolerance of several probiotic strains was measured quantitatively using an index known as Relative Bacterial Growth Ratio (RBGR). The tolerance to oxygen varied between organisms, and this technique can therefore be applied for screening probiotic bacteria for oxygen tolerance.

Growth and survival of a probiotic yeast in dairy products

Poor survival of probiotic bacteria in yogurt has been recorded. Growth of a probiotic yeast, Saccharomyces boulardii, in association with the bio-yogurt microflora, by incorporating the yeast into commercial bio-yogurt, has been suggested to stimulate the growth of the probiotic organisms and to assure their survival during shelflife. Therefore, the ability of growth and survival of the probiotic yeast itself in diary products, namely bio-yogurt, UHT yogurt and UHT milk were investigated. S. boulardii was incorporated into the dairy products and stored at 4°C over a 4-week period. pH, Lactose utilisation and the production of organic acids were monitored at each interval. Based on the results in this study, the probiotic yeast species, S. boulardii, has the ability to grow in bio-yogurt reaching maximum counts exceeding 107 cfu/g. The number of yeast populations was substantially higher in the fruit based yogurt, mainly due to the presence of proportions of sucrose and fructose derived from the fruit. Despite the inability of S. boulardii to utilize lactose, the yeast species utilized available organic acids, galactose and glucose derived from bacterial metabolism of the milk sugar lactose present in the dairy products. Excessive gas and alcohol production by the yeast species proved, however, to be major constraints for incorporating this yeast into bio-yogurt.

Environmental adaptation of probiotic lactobacilli towards improvement of performance during spray drying

Abstract The potential of environmental adaptation as a survival mechanism enabling a human-derived probiotic Lactobacillus strain to withstand heat stress and spray drying was investigated. Heat-adapted (52°C for 15 min) L. paracasei NFBC 338 exhibited 300- and 700-fold greater thermotolerance (survival at a lethal temperature of 60°C) compared with controls, in MRS and reconstituted skim milk (RSM), respectively. The level of thermal protection in RSM by pre-adaptation in hydrogen peroxide (0.003 m ), salt (0.3 m NaCl) and bile salts (0.1% w/v) was also examined. Although not as efficient as the homologous stress, the levels of cross protection were in the order heat>salt>hydrogen peroxide>bile. Viability of the heat-adapted L. paracasei NFBC 338 in RSM was enhanced 18-fold during spray drying at outlet temperatures of 95–105°C, while salt-adapted cultures exhibited 16-fold greater viability than controls. These results highlight the potential of preconditioning treatments for maximizing survival of probiotic bacteria during development of probiotic functional foods. The cross protection afforded by salt against thermal stress may indicate that certain common protective mechanisms are induced by both heat and salt stress.

Probiotic Bacteria: Selective Enumeration and Survival in Dairy Foods

A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidophilus, Bifidobacterium spp., and Lactobacillus casei. Because of the potential health benefits, these organisms are increasingly incorporated into dairy foods. However, studies have shown low viability of probiotics in market preparations. In order to assess viability of probiotic bacteria, it is important to have a working method for selective enumeration of these probiotic bacteria. Viability of probiotic bacteria is important in order to provide health benefits. Viability of probiotic bacteria can be improved by appropriate selection of acid and bile resistant strains, use of oxygen impermeable containers, two-step fermentation, micro-encapsulation, stress adaptation, incorporation of micronutrients such as peptides and amino acids and by sonication of yogurt bacteria. This review will cover selective enumeration and survival of probiotic bacteria in dairy foods.

Characteristics of carbonated fermented milk and survival of probiotic bacteria

Fil: Vinderola, Celso Gabriel. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Prog.de Lactologia Industrial; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina