Sensory evaluation and inhibition of Listeria monocytogenes in bovine pâté added of chitosan from Mucor rouxii

This study aimed to assess the efficacy of chitosan from Mucor rouxii UCP 064 in inhibiting Listeria monocytogenes in bovine meat pâté at 4 °C. The influence of the chitosan addition on sensory aspects of the product was also evaluated. The addition of chitosan from M. rouxii at 5 mg/g to bovine meat pâté decreased the counts of L. monocytogenes from approximately 7 to 3 log cfu/g after 6 days of storage at 4 °C. In pâté without chitosan the counts were over 7 log cfu/g already after two days of storage. Sensory evaluation suggested that addition of chitosan in pâté would be acceptable to consumers, although some negative influence on flavor and taste was found. From these results, chitosan from fungi could be considered a possible alternative compound to control L. monocytogenes in ready-to-eat meat products.     

Taxonomic and molecular characterization of lactic acid bacteria and yeasts in nunu,a Ghanaian fermented milk product

Produced from raw unpasteurized milk, nunu is a spontaneously fermented yoghurt-like product made in Ghana and other parts of West Africa. Despite the importance of nunu in the diet of many Africans, there is currently only limited information available on the microorganisms associated with nunu processing. With the aim of obtaining a deeper understanding of the process and as a first step towards developing starter cultures with desired technological properties for nunu production, a microbiological characterization of nunu processing in three different towns in the Upper East region of Ghana, namely Bolgatanga, Paga and Navrongo, was carried out. Lactic acid bacteria (LAB) and yeasts associated with nunu processing were isolated and identified using a combination of pheno- and genotypic methods including morphological and carbohydrate fermentation tests, (GTG)₅-based rep-PCR, multiplex PCR, and 16S and 26S rRNA gene sequencing. The LAB counts during nunu processing increased from 4.5 ± 0.4 log cfu/ml at 0 h to 8.7 ± 1.8 log cfu/ml at 24 h of fermentation while yeasts counts increased from 2.8 ± 1.2 log cfu/ml at 0 h to 5.8 ± 0.5 log cfu/ml by the end of fermentation. Lactobacillus fermentum was the dominant LAB throughout the fermentations with Lactobacillus plantarum and Leuconostoc mesenteroides playing prominent roles during the first 6–8 h of fermentation as well. Less frequently isolated LAB included Lactobacillus helveticus, Enterococcus faecium, Enterococcus italicus, Weissella confusa and a putatively novel Lactococcus spp. The yeasts involved were identified as Candida parapsilosis, Candida rugosa, Candida tropicalis, Galactomyces geotrichum, Pichia kudriavzevii and Saccharomyces cerevisiae with P. kudriavzevii and S. cerevisiae being the dominant yeast species.     

Microbiological,physicochemical and rheological properties of fermented soymilk produced with exopolysaccharide (EPS) producing lactic acid bacteria strains

Growth of Lactobacillus plantarum 70810, Lactobacillus rhamnosus 6005 and a commercial yogurt starter culture in soymilk was investigated in the present study. It was found that the fermented soymilk using L. plantarum 70810 had significantly higher viable cell counts, water holding capacity (WHC, 88.27%), apparent viscosity (1840.35 mPa s) and exopolysaccharide (EPS) amount (832.15 mg/L) than the other two starter cultures in soymilk. Direct observation of microstructure in fermented soymilk indicated that the network structures of EPS-protein could improve the texture of fermented soymilk. Considering that the beneficial effects of L. plantarum 70810 in fermented soymilk, volatile compounds in fermented soymilk were further identified. Then the growth and fermentation characteristics of L. plantarum 70810 including changes in viable cell counts, pH, titratable acidity, apparent viscosity and EPS production during storage were investigated. In comparison to original soymilk base, the concentrations of the characteristic flavor compounds for fermented soymilk using L. plantarum 70810 increased, whereas hexanal, 2-pentylfuran and 2-pentanone in relation to beany flavor of soymilk decreased. In addition, fermented soymilk using L. plantarum 70810 maintained high viable cell count (>10⁸ cfu/mL), apparent viscosity (966.43 mPa s) and amounts of EPS (635.49 mg/mL) during storage at 4 °C for 21 days.     

Survival of Listeria innocua in dry fermented sausages and changes in the typical microbiota and volatile profile as affected by the concentration of nitrate and nitrite

The involvement of nitrate and nitrite in the formation of N-nitrosamines in foods is a matter of great concern. This situation has led to revise the real amount of nitrate and nitrite needed in meat products to exert proper technological and safety activities, and also to extensive research to find alternatives to their use. The present study addresses the possibility of reducing the ingoing amounts of these additives below the legal limits established by the current European regulations. Different concentrations of nitrate and nitrite were tested on Spanish salchichón-type dry fermented sausages concerning their role in the microbiota and volatile profile. Sausages were manufactured with the maximum ingoing amounts established by the EU regulations (150 ppm NaNO₃ and 150 ppm NaNO₂), a 25% reduction and a 50% reduction; control sausages with no nitrate/nitrite addition were also prepared. The mixtures were inoculated with 5 log cfu/g of Listeria innocua as a surrogate for Listeria monocytogenes. L. innocua numbers in the final product were approximately 1.5 log cfu/g lower in the batch with the maximum nitrate/nitrite concentration when compared to 25 and 50% reduced batches, and about 2 log cfu/g in comparison to the control sausages. The final numbers of catalase-positive cocci were 1 log cfu/g higher in the 50% nitrate/nitrite reduced batch and 2 log cfu/g higher in the control sausages, compared to products manufactured with the maximum nitrate/nitrite concentration. This increase was related to a higher amount of volatile compounds derived from carbohydrate fermentation and amino acid degradation. Sausages with no addition of nitrate/nitrite showed higher amount of volatiles from lipid oxidation. Enterobacteriaceae counts reached detectable values (1-2 log cfu/g) in both nitrate/nitrite reduced sausages and in the control batch, while these organisms were not detected in the batch with the maximum ingoing amount. Nitrate and nitrite exerted a significant effect on the typical microbiota of dry fermented sausages and effectively contributed to control Listeria. These considerations should be taken into account in view of a future restriction in the use of these curing additives.     

Microbiological quality of artisanal Sepet cheese

Microbial diversity in milk and in cheese itself affects the biochemical and sensory characteristics of artisanal cheeses. In this study, the microflora of Sepet cheese, which is a traditional artisanal cheese in Turkey, was investigated. Average lactococci, lactobacilli, enterococci, yeast, mould, coliform, psychrotrophic and total aerobic bacteria, presumptive Staphylococcus aureus counts were; 7.31 ± 1.08, 7.19 ± 1.02, 6.84 ± 0.92, 3.19 ± 1.40, 0.84 ± 0.89, 2.18 ± 1.81, 4.92 ± 1.15, 7.53 ± 1.13 and 1.25 ± 1.70 log cfu/g, respectively. Staphylococci, coliform and mould counts were less than 1.00 log cfu/g at the end of ripening, which was at around 6–8 °C for 3 months. According to phenotypic and genotypic identifications, isolates were closely related to Lactobacillus plantarum, Weisella confusa, Weisella paramesenteroides, Pediococcus pentasaceous, Enterococcus casseliflavus, Enterococcus durans and Enterococcus faceium. This study provides baseline data on the microflora of traditional artisanal Sepet cheese, which is a prerequisite for a successful scale up to industrial production.     

The substitution of a traditional starter culture in mutton fermented sausages by Lactobacillus acidophilus and Bifidobacterium animalis

Common starter cultures used in fermented mutton sausages were substituted by probiotic strains of Lactobacillus acidophilus CCDM 476 and Bifidobacterium animalis 241a. Technological properties of the traditional and the probiotic sausages were compared. The potential probiotic effect was evaluated by enumeration of bifidobacteria and lactobacilli in stool samples of 15 volunteers before and after a 14-day consumption period. The numbers of lactobacilli (10⁷ cfu/g) and bifidobacteria (10³ cfu/g) in the final product did not affect the technological properties. The use of L. acidophilus as a starter culture was found more beneficial than the use of B. animalis. Even after 60 days of storage, high counts of L. acidophilus (10⁶ cfu/g) were detected; on the other hand, the counts of B. animalis were under the detection limit. Regarding sensory properties, the probiotic products showed better texture, and, curiously, a reduction of the typical smell of mutton. The numbers of lactobacilli in stool samples increased significantly after the consumption of the probiotic sausages.     

Microbiological attributes and biogenic amine content of probiotic Turkish fermented sausage

Microbiological attributes and biogenic amine content of Turkish fermented sausage manufactured by using probiotic starter cultures (Lactobacillus casei, L. acidophilus or their combination) were investigated before and after fermentation-drying period and during refrigerated storage at 4 ± 1 °C for 8 months at 2 month intervals. As results of the study, during fermentation and storage biogenic amine content (histamine, putrescine, cadaverine and tyramine) of the samples were increased significantly. Salmonella, Staphylococcus aureus, coliform and fecal coliform microorganisms were not detected during fermentation and storage. Probiotic microorganism counts of all samples were higher than the lower limit of 6.0 log cfu/g which is requested for probiotic foods.     

发酵剂对发酵香肠微生物及理化特性的影响

采用3种复合型发酵剂(VBL-97、VBM-60、SHI-59)和1种单一型发酵剂(BOM-13)生产发酵香肠,研究不同发酵剂对发酵香肠微生物及理化性质的影响。结果表明4组发酵香肠在发酵和成熟过程中,乳酸菌始终保持为优势菌,当达到成熟时,乳酸菌数在7.21~8.13 lgcfu/g范围内,葡萄球菌(除BOM-13外)高于5.50 lgcfu/g,肠杆菌科菌数低于3.00 lgcfu/g。BOM-13型发酵剂由单一清酒乳杆菌组成,发酵和成熟时间长于其他三组,所以成品的硫代巴比妥酸值(TBARS值,0.84 mg/100 g)和非蛋白氮值(NPN,0.46%)高于其它3组产品。由此可知由于发酵剂组成不同,相应地发酵条件(温度和时间)和成熟时间亦不同,但最终四种发酵剂都可生产出高品质产品(p H值5.3;AW0.82;NPN值高;TBARS值1.0 mg/kg;乳酸菌为优势菌且7.0 lgcfu/g;肠杆菌科菌3.0lgcfu/g)。VBL-97型发酵剂产酸能力和抗氧化能力强,而BOM-13型发酵香肠蛋白分解程度最高。     

Microbiological attributes and biogenic amine content of probiotic Turkish fermented sausage

Microbiological attributes and biogenic amine content of Turkish fermented sausage manufactured by using probiotic starter cultures (Lactobacillus casei, L. acidophilus or their combination) were investigated before and after fermentation-drying period and during refrigerated storage at 4?±?1?°C for 8?months at 2?month intervals. As results of the study, during fermentation and storage biogenic amine content (histamine, putrescine, cadaverine and tyramine) of the samples were increased significantly. Salmonella, Staphylococcus aureus, coliform and fecal coliform microorganisms were not detected during fermentation and storage. Probiotic microorganism counts of all samples were higher than the lower limit of 6.0 log cfu/g which is requested for probiotic foods.     

Heat shock effects on the viability of Cronobacter sakazakii during the dehydration,fermentation, and storage of lactic cultured milk products

In the present study, the viability of heat-shocked and non-shocked Cronobacter sakazakii, a foodborne pathogen, after drying and during the fermentation as well as storage of lactic cultured milk was evaluated. It was found that heat shock increased the viability of C. sakazakii. The pure culture of C. sakazakii, regardless of heat shock, grew rapidly in skim milk with a viable population of ca. 8.59–8.70 log cfu/ml after ca. 48 h of cultivation. Thereafter, the viable population of C. sakazakii remained stable. While in the mix culture with Streptococcus thermophilus or Lactobacillus bulgaricus, a marked reduction in the viable population of C. sakazakii was noted after 24 h of cultivation in skim milk. Nevertheless, at the end of fermentation, the heat-shocked C. sakazakii had a viable population of 5.93–6.01 log cfu/ml, which is significantly higher (P < 0.05) than that of non-shocked cells of 4.96–4.99 log cfu/ml. While the presence of C. sakazakii did not affect the growth of lactic acid bacteria in skim milk. Additionally, heat shock was found to enhance the survival of C. sakazakii after freeze-drying or spray-drying and during the storage of the lactic fermented milk products (pH 4.3) at 5 °C for 48 h.     

Suitability of selected autochthonous lactic acid bacteria cultures for Pecorino Sardo Dolce cheese manufacturing: influence on microbial composition,nutritional value and sensory attributes

The use of an autochthonous starter culture made up by Streptococcus thermophilus, Lactococcus lactis subsp. lactis, Lactobacillus plantarum and Lactobacillus casei in the production of experimental Pecorino Sardo Dolce PDO resulted in a high presence of presumptive mesophilic lactococci and lactobacilli, ~10 log colony‐forming units (cfu), and in significantly higher amount of total free amino acids and free fatty acids, 195.1 vs 178.9 and 328.6 vs 191.8 mg/100 g of experimental vs control cheese (made using a commercial starter) respectively. The experimental cheese also displayed better sensory properties such as taste and aftertaste.     

Microbiological and chemical characterisation of ting, a sorghum-based sourdough product from Botswana

Ting is a fermented sorghum product of Botswana which is used to prepare porridges of different consistencies. This study aimed to characterise ting with respect to fermentation microbiota and metabolite composition, and to develop starter cultures for ting fermentation. The pH values of 10 ting samples from Botswana ranged between 3.5 and 4.0 and cell counts ranged between 1.2×10(8) and 1.2×10(10)cfu/g lactic acid bacteria. Yeast cell counts were below 10(5)cfu/g in all samples and Enterobacteriaceae were less than 10 cfu/g. The microbiota of samples consisted of 2-4 dominant strains and strains were identified based on the sequence of their 16S rRNA genes as Lactobacillus reuteri, Lactobacillus fermentum, Lactobacillus harbinensis, Lactobacillus plantarum, Lactobacillus parabuchneri, Lactobacillus casei and Lactobacillus coryniformis. Binary strain combinations were employed as starter cultures to produce ting. Major fermentation products were lactate, acetate and ethanol, additionally, 1,2 propanediol and 1,3 propanediol were produced by some strains. All strains were capable of producing ting, which was accompanied by a decrease in pH from 6.3 to 4 within 8h. Traditionally processed ting requires 2 to 3 days to attain a pH below 4; the starter cultures thus reduced the fermentation time to 8h.     

Diversity of lactic acid bacteria associated with traditional fermented dairy products in Mongolia

Spontaneous milk fermentation has a long history in Mongolia, and beneficial microorganisms have been handed down from one generation to the next for use in fermented dairy products. The objective of this study was to investigate the diversity of lactic acid bacteria (LAB) communities in fermented yak, mare, goat, and cow milk products by analyzing 189 samples collected from 13 different regions in Mongolia. The LAB counts in these samples varied from 3.41 to 9.03 log cfu/mL. Fermented yak and mare milks had almost identical mean numbers of LAB, which were significantly higher than those in fermented goat milk but slightly lower than those in fermented cow milk. In total, 668 isolates were obtained from these samples using de Man, Rogosa, and Sharpe agar and M17 agar. Each isolate was considered to be presumptive LAB based on gram-positive and catalase-negative properties, and was identified at the species level by 16S rRNA gene sequencing, multiplex PCR assay, and restriction fragment length polymorphism analysis. All isolates from Mongolian dairy products were accurately identified as Enterococcus faecalis (1 strain), Enterococcus durans (3 strains), Lactobacillus brevis (3 strains), Lactobacillus buchneri (2 strains), Lactobacillus casei (16 strains), Lactobacillus delbrueckii ssp. bulgaricus (142 strains), Lactobacillus diolivorans (17 strains), Lactobacillus fermentum (42 strains), Lactobacillus helveticus (183 strains), Lactobacillus kefiri (6 strains), Lactobacillus plantarum ssp. plantarum (7 strains), Lactococcus lactis ssp. lactis (7 strains), Leuconostoc lactis (22 strains), Leuconostoc mesenteroides (21 strains), Streptococcus thermophilus (195 strains), and Weissella cibaria (1 strain). The predominant LAB were Strep. thermophilus and Lb. helveticus, which were isolated from all sampling sites. The results demonstrate that traditional fermented dairy products from different regions of Mongolia have complex compositions of LAB species. Such diversity of LAB provides useful information for further studies of probiotic strain selection and starter culture design, with regard to the industrial production of traditional fermented milk.     

Probiotic viability and storage stability of yogurts and fermented milks prepared with several mixtures of lactic acid bacteria

Currently, the food industry wants to expand the range of probiotic yogurts but each probiotic bacteria offers different and specific health benefits. Little information exists on the influence of probiotic strains on physicochemical properties and sensory characteristics of yogurts and fermented milks. Six probiotic yogurts or fermented milks and 1 control yogurt were prepared, and we evaluated several physicochemical properties (pH, titratable acidity, texture, color, and syneresis), microbial viability of starter cultures (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) and probiotics (Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus reuteri) during fermentation and storage (35 d at 5°C), as well as sensory preference among them. Decreases in pH (0.17 to 0.50 units) and increases in titratable acidity (0.09 to 0.29%) were observed during storage. Only the yogurt with S. thermophilus, L. delbrueckii ssp. bulgaricus, and L. reuteri differed in firmness. No differences in adhesiveness were determined among the tested yogurts, fermented milks, and the control. Syneresis was in the range of 45 to 58%. No changes in color during storage were observed and no color differences were detected among the evaluated fermented milk products. Counts of S. thermophilus decreased from 1.8 to 3.5 log during storage. Counts of L. delbrueckii ssp. bulgaricus also decreased in probiotic yogurts and varied from 30 to 50% of initial population. Probiotic bacteria also lost viability throughout storage, although the 3 probiotic fermented milks maintained counts ≥10⁷ cfu/mL for 3 wk. Probiotic bacteria had variable viability in yogurts, maintaining counts of L. acidophilus ≥10⁷ cfu/mL for 35 d, of L. casei for 7 d, and of L. reuteri for 14 d. We found no significant sensory preference among the 6 probiotic yogurts and fermented milks or the control. However, the yogurt and fermented milk made with L. casei were better accepted. This study presents relevant information on physicochemical, sensory, and microbial properties of probiotic yogurts and fermented milks, which could guide the dairy industry in developing new probiotic products.     

Identification of potential probiotic starter cultures for Scandinavian-type fermented sausages

Potential probiotic cultures suitable as starter cultures for the Scandinavian-type fermented sausages were identified among strains well-adapted to fermented meats as well as strains originating from a culture collection. From 15 different fermented meat products, 22 strains were isolated as dominant non-starter lactic acid bacteria (NSLAB). The isolates were identified by RAPD, API and sequence analysis of 16S rRNA and showed to be five strains of Lactobacillus sakei, five strains of Lactobacillus farciminis, five strains belonging to the group of Lactobacillus plantarum/pentosus, four strains of Lactobacillus alimentarius, two strains of Lactobacillus brevis and one strain of Lactobacillus versmoldensis. Heterofermentative strains as well as strains not growing at 37 degrees C and not lowering pH below 5.1 in a meat model were excluded leaving 9 strains for further studies. These strains together with 19 strains from a culture collection were evaluated by in vitro methods including survival upon exposure to pH 2.5 or 0.3% oxgall and adhesion to the human colon adenocarcinoma cell line Caco-2 as well as antimicrobial activity against potential pathogens. Strains that fulfilled all the probiotic criteria and showed to be fast acid producers in a meat model included three strains belonging to the group of Lb. plantarum/pentosus (MF1291, MF1298, MF1300) which originated from the dominant NSLAB of fermented meat products. MF1291 and MF 1298 were further identified as Lb. plantarum and MF1300 as Lb. pentosus. The three strains were all successfully applied as starter cultures for the production of fermented sausage. The viable count at the end of the processing period reached high cell numbers (4.7x10(7)-2.9x10(8) cfu/g) and pH of the sausages decreased to pH 4.8-4.9 without any flavour deviation compared to sausage fermented by a commercial meat starter culture.     

微生物亚硝化抑制剂对风干肠发酵成熟期间微生物菌落变化的影响及其感官评价分析

为研究微生物亚硝化抑制剂（microbial nitrosation inhibitor,MNI）对风干肠发酵和成熟过程中微生物群落动态变化及感官特性的影响,该试验设计4组风干肠,MNI组：添加MNI;MNIP组：添加MNI并接入PRO-MIX5商业发酵剂（木糖葡萄球菌、清酒乳杆菌、类植物乳杆菌）;FBFAP组：发酵牛骨调味基料和复配抗氧化剂（fermented beef flavorings and compound antioxidant,FBFA）并接入PRO-MIX5;CK组。结果表明：在发酵阶段,4组风干肠乳酸菌数逐渐增多,MNI组和MNIP肉馅分别在发酵的15 h、12.5 h达到发酵终点即pH降到5.4~5.6,乳酸菌数分别为8.99 lg cfu/g、8.91 lg cfu/g,显著高于CK组发酵终点（22 h）的乳酸菌数8.88 lg cfu/g（p<0.05）。到成熟终点时,革兰氏阴性腐败微生物在MNI组的相对丰度占比最低（19.35%）,对肠杆菌科和假单胞菌的抑制率分别为30.43%、27.22%,仅次于MNIP组37.00%、33.79%,优于CK组和FBFAP组。综合分析,MNI能作为促生长因子,促进肉馅中乳酸杆菌属菌的生长,在接种有发酵剂PRO-MIX5的风干肠中加入MNI对腐败微生物的抑制效果优于FBFAP。单独添加MNI或MNI与PRO-MIX5协同作用均能提高风干肠微生物安全性和感官性能,说明MNI在提高风干肠安全品质方面具有广阔的应用前景。     

Effects of electron-beam and gamma irradiation treatments on the microbial populations, respiratory activity and sensory characteristics of Tuber melanosporum truffles packaged under modified atmospheres

The effects of electron-beam or gamma irradiation (doses of 1.5 kGy and 2.5 kGy of either one) on the microbial populations, respiratory activity and sensory characteristics of Tuber melanosporum packaged under modified atmospheres were monitored immediately after treatment, and subsequently every seven days during 35 days of storage at 4 °C. Treatments with 1.5 and 2.5 kGy reduced the total mesophilic aerobes counts respectively by 4.3 and 5.6 log cfu/g for electron-beam treatment, and by 6.4 and 6.6 log cfu/g for gamma irradiation. Other microbial groups studied (Pseudomonas genus, Enterobacteriaceae family, lactic acid bacteria, mesophilic aerobic spores, molds and yeasts) were not detected after the treatments. A decrease in the respiratory activity was detected in all the irradiated batches, indicating that the carbon dioxide levels were lower and the oxygen levels higher than those of the non-irradiated ones. Two species of yeasts, Candida sake and Candida membranifaciens var. santamariae, survived the irradiation treatments and became the dominant microbial populations with counts of up to 7.0 log cfu/g. The growth of these microorganisms was visible on the surface of irradiated truffles from day 21 onwards, affecting the flavor and the general acceptability of the ascocarps. Moreover, a watery exudate was detected in the treated truffles from the third week onwards, so the application of irradiation treatments in doses equal to or above 1.5 kGy did not preserve the quality characteristics of T. melanosporum truffles beyond 28 days.     

Diversity and probiotic potentials of lactic acid bacteria isolated from gilaburu,a traditional Turkish fermented European cranberrybush (Viburnum opulus L.) fruit drink

The aim of the present study was to characterize lactic acid bacteria (LAB) strains isolated from traditional fermented gilaburu fruit juice and their probiotic potential. The LAB counts of the fermented gilaburu fruit juice were in the range of 3.92–8.30 log cfu/g. Total of 332 isolates belonging to Lactobacillus and Leuconostoc species were characterized from traditional fermented gilaburu juice by genotypic methods. It was also determined that the major LAB strains belong to Lactobacillus plantarum (173 isolates), Lactobacillus casei (52 isolates) and Lactobacillus brevis (24 isolates), while Lactobacillus buchneri, Lactobacillus parabuchneri, Lactobacillus pantheris, Leuconostoc pseudomesenteroides and Lactobacillus harbinensis were the least in isolated LAB strains. In terms of the probiotic potentials, Lb. plantarum strains were able to grow at pH 2.5, but 3 of Lb. casei strains, one of each Lb. brevis and Lb. buchneri strains could not grow at the same pH. All selected LAB stains were resistant to bile salt at ≤ 0.3% concentration. While all the LAB species grew at 15 °C, two Lactobacillus hordei strains could also grow at 45 °C. The highest cell hydrophobicity degrees were for Lb. casei (G20a) and Lb. plantarum (G19e) as 87.5 and 86.0%, respectively. Listeria monocytogenes and Bacillus cereus were the most sensitive bacteria against the selected LAB strains, while Escherichia coli and Staphylococcus aureus were the most resistant. Again all the isolated LAB species were resistant to three antibiotics; kanamycin, streptomycin and vancomycin. Characterization and probiotic potentials of the LAB isolated from fermented gilaburu (Viburnum opulus) juice were studied first time, and further research needs to be done on their behaviors in similar food formulations as a probiotic.     

Effect of trehalose and lactose as cryoprotectant during freeze‐drying,in vitro gastro‐intestinal transit and survival of microencapsulated freeze‐dried Lactobacillus casei 431 cells

A novel microencapsulation technique for Lactobacillus casei 431 cells was developed, and the bacterial stability was studied. Cryoprotective solutes were incorporated in the encapsulation mix to improve freeze‐drying survival. The losses of viable cells during drying were recorded as 1.7, 0.84 and 0.38 log Colony‐forming units (cfu)/g for control and samples with trehalose and lactose, respectively. During the simulated gastric‐intestinal transit, trehalose and lactose contributed to higher survivals of 3.1 and 3.0 log cfu/g, respectively, in gastric fluid and 1.3 log and 0.9 log cfu/g, respectively, in 1% bile extract solution. Higher temperature storage was found to be detrimental for cell viability.