Isolation and identification of cultivable lactic acid bacteria in traditional yak milk products of Gansu Province in China

Various traditional fermented yak milk and raw milk foods could be considered as an abundant resource for obtaining novel lactic acid bacteria (LAB) with unique properties. Eighty-eight samples of yak milk products were collected from Gansu Province in China. Three hundred and nineteen strains of LAB isolated from these samples were identified by phenotypic methods, 16S rRNA gene sequence analysis and PCR-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) technology. Among the isolates, one hundred and sixty-four isolates (51.41% of the total) were classified under Lactobacilli, and one hundred and fifty-five (48.59%) belonged to cocci. All the isolates were classified to six genera (Lactobacillus, Lactococcus, Leuconostoc, Streptococcus, Enterococcus and Weissella) and twenty-one species. Lactobacillus helveticus (87 strains), Leuconostoc mesenteroides subsp. mesenteroides (49 strains), Streptococcus thermophilus (39 strains), Lactobacillus casei (31 strains) and Lactococcus lactis subsp. lactis (19 strains) were considered as the predominant populations in the yak milk products. The results showed that there were abundant genus and species LAB existing in yak milk products in Gansu Province in China. The obtained LAB pure cultures may be a valuable source for further starter selection.     

Phylogenetic diversity of lactic acid bacteria associated with paddy rice silage as determined by 16S ribosomal DNA analysis

A total of 161 low-G+C-content gram-positive bacteria isolated from whole-crop paddy rice silage were classified and subjected to phenotypic and genetic analyses. Based on morphological and biochemical characters, these presumptive lactic acid bacterium (LAB) isolates were divided into 10 groups that included members of the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and WEISSELLA: Analysis of the 16S ribosomal DNA (rDNA) was used to confirm the presence of the predominant groups indicated by phenotypic analysis and to determine the phylogenetic affiliation of representative strains. The virtually complete 16S rRNA gene was PCR amplified and sequenced. The sequences from the various LAB isolates showed high degrees of similarity to those of the GenBank reference strains (between 98.7 and 99.8%). Phylogenetic trees based on the 16S rDNA sequence displayed high consistency, with nodes supported by high bootstrap values. With the exception of one species, the genetic data was in agreement with the phenotypic identification. The prevalent LAB, predominantly homofermentative (66%), consisted of Lactobacillus plantarum (24%), Lactococcus lactis (22%), Leuconostoc pseudomesenteroides (20%), Pediococcus acidilactici (11%), Lactobacillus brevis (11%), Enterococcus faecalis (7%), Weissella kimchii (3%), and Pediococcus pentosaceus (2%). The present study, the first to fully document rice-associated LAB, showed a very diverse community of LAB with a relatively high number of species involved in the fermentation process of paddy rice silage. The comprehensive 16S rDNA-based approach to describing LAB community structure was valuable in revealing the large diversity of bacteria inhabiting paddy rice silage and enabling the future design of appropriate inoculants aimed at improving its fermentation quality.     

Identification of Carnobacterium spp. and Leuconostoc spp. in meat by genus-specific 16S rRNA probes

Oligonucleotide probes specific for Carnobacterium and Leuconostoc species were constructed from the variable regions of 16S rRNA obtained from the literature and sequence data bases. The probes were hybridized with crude nucleic acid extract from 32 type strains of lactic acid bacteria (LAB) commonly found on meat. Two of the probes hybridized only to the four Carnobacterium species whereas the other two hybridized only to five of the six Leuconostoc species tested. The probes were also hybridized with nucleic acids from unknown strains of LAB. The identification was consistent with the results of biochemical tests used to characterize the two genera.     

Phenotypic and phylogenetic analysis of lactic acid bacteria isolated from forage crops and grasses in the Tibetan Plateau

A total of 140 lactic acid bacteria (LAB) strains were isolated from corn, alfalfa, clover, sainfoin, and Indian goosegrass in the Tibetan Plateau. According to phenotypic and chemotaxonomic characteristics, 16S rDNA sequence, and recA gene PCR amplification, these LAB isolates were identified as belonging to five genera and nine species. Corn contained more LAB species than other forage crops. Leuconostoc pseudomesenteroides, Lactococcus lactis subsp. lactis, Lactobacillus brevis, and Weissella paramesenteroides were dominant members of the LAB population on alfalfa, clover, sainfoin, and Indian goosegrass, respectively. The comprehensive 16S rDNA and recA-based approach effectively described the LAB community structure of the relatively abundant LAB species distributed on different forage crops. This is the first report describing the diversity and natural populations of LAB associated with Tibetan forage crops, and most isolates grow well at or below 10°C. The results will be valuable for the future design of appropriate inoculants for silage fermentation in this very cold area.     

Dynamics and biodiversity of populations of lactic acid bacteria and acetic acid bacteria involved in spontaneous heap fermentation of cocoa beans in Ghana

The Ghanaian cocoa bean heap fermentation process was studied through a multiphasic approach, encompassing both microbiological and metabolite target analyses. A culture-dependent (plating and incubation, followed by repetitive-sequence-based PCR analyses of picked-up colonies) and culture-independent (denaturing gradient gel electrophoresis [DGGE] of 16S rRNA gene amplicons, PCR-DGGE) approach revealed a limited biodiversity and targeted population dynamics of both lactic acid bacteria (LAB) and acetic acid bacteria (AAB) during fermentation. Four main clusters were identified among the LAB isolated: Lactobacillus plantarum, Lactobacillus fermentum, Leuconostoc pseudomesenteroides, and Enterococcus casseliflavus. Other taxa encompassed, for instance, Weissella. Only four clusters were found among the AAB identified: Acetobacter pasteurianus, Acetobacter syzygii-like bacteria, and two small clusters of Acetobacter tropicalis-like bacteria. Particular strains of L. plantarum, L. fermentum, and A. pasteurianus, originating from the environment, were well adapted to the environmental conditions prevailing during Ghanaian cocoa bean heap fermentation and apparently played a significant role in the cocoa bean fermentation process. Yeasts produced ethanol from sugars, and LAB produced lactic acid, acetic acid, ethanol, and mannitol from sugars and/or citrate. Whereas L. plantarum strains were abundant in the beginning of the fermentation, L. fermentum strains converted fructose into mannitol upon prolonged fermentation. A. pasteurianus grew on ethanol, mannitol, and lactate and converted ethanol into acetic acid. A newly proposed Weissella sp., referred to as "Weissella ghanaensis," was detected through PCR-DGGE analysis in some of the fermentations and was only occasionally picked up through culture-based isolation. Two new species of Acetobacter were found as well, namely, the species tentatively named "Acetobacter senegalensis" (A. tropicalis-like) and "Acetobacter ghanaensis" (A. syzygii-like).     

Species diversity and relative abundance of vaginal lactic acid bacteria from women in Uganda and Korea

AIMS: Lactobacilli play an important role in maintaining vaginal health of women. The aim of this study was to compare the species richness and relative abundance of Lactobacillus and other lactic acid bacteria in women of two geographically distant countries, Uganda and Korea. METHODS AND RESULTS: Vaginal samples were obtained from two women populations in Uganda and Korea. The Lactobacillus Rogosa SL agar was used for initial isolation of lactic acid bacteria. After phenotypic analyses, the 16S rRNA gene was amplified by polymerase-chain reaction and analysed by the BLAST program and phylogenetic tree construction. A total of 338 (128 Korean and 210 Ugandan) vaginal lactic acid bacterial strains were isolated, including five genera: Lactobacillus, Leuconostoc, Pediococcus, Streptococcus and Weissella. While Lactobacillus crispatus was common in both populations, Lactobacillus fermentum was common only in Korean women, and Lactobacillus gasseri, Lactobacillus reuteri and Lactobacillus vaginalis only in Ugandan women. Among other lactic acid bacteria, Weissella was more common in Ugandan, and Pediococcus in Korean women. All Weissella strains produced hydrogen peroxide, and all Pediococcus strains inhibited Candida species. CONCLUSION: Although many lactic acid bacteria colonize women, their species distributions may be different in women of geographically separated communities. SIGNIFICANCE AND IMPACT OF THE STUDY: The knowledge of species richness and relative abundance of vaginal lactic acid bacteria, including Lactobacillus, Pediococcus and Weissella, may lead to the design of better probiotic products as bacterial replacement therapy.     

Bacteriophage ecology in commercial sauerkraut fermentations

Knowledge of bacteriophage ecology in vegetable fermentations is essential for developing phage control strategies for consistent and high quality of fermented vegetable products. The ecology of phages infecting lactic acid bacteria (LAB) in commercial sauerkraut fermentations was investigated. Brine samples were taken from four commercial sauerkraut fermentation tanks over a 60- or 100-day period in 2000 and 2001. A total of 171 phage isolates, including at least 26 distinct phages, were obtained. In addition, 28 distinct host strains were isolated and identified as LAB by restriction analysis of the intergenic transcribed spacer region and 16S rRNA sequence analysis. These host strains included Leuconostoc, Weissella, and Lactobacillus species. It was found that there were two phage-host systems in the fermentations corresponding to the population shift from heterofermentative to homofermentative LAB between 3 and 7 days after the start of the fermentations. The data suggested that phages may play an important role in the microbial ecology and succession of LAB species in vegetable fermentations. Eight phage isolates, which were independently obtained two or more times, were further characterized. They belonged to the family Myoviridae or Siphoviridae and showed distinct host ranges and DNA fingerprints. Two of the phage isolates were found to be capable of infecting two Lactobacillus species. The results from this study demonstrated for the first time the complex phage ecology present in commercial sauerkraut fermentations, providing new insights into the bioprocess of vegetable fermentations.     

A TaqMan-based real-time PCR assay for the specific detection and quantification of Leuconostoc mesenteroides in meat products

A new real-time PCR procedure was developed for the specific detection and quantification of Leuconostoc mesenteroides in meat products. It is a TaqMan assay based on 23S rRNA gene targeted primers and probe. Specificity was evaluated using purified DNA from 132 strains: 102 lactic acid bacteria (LAB), including 57 reference strains and 46 food isolates, belonging to genus Leuconostoc and related genera, and 30 non-LAB strains. Quantification was linear over at least 5 log units using both serial dilutions of purified DNA and calibrated cell suspensions from Leuconostoc mesenteroides ssp. dextranicum CECT 912T. This assay was able to detect at least five genomic equivalents, using purified DNA or 59 CFU per reaction when using calibrated cell suspensions. It performed successfully when tested on an artificially inoculated meat product, with a minimum threshold of 10(4) CFU g(-1) for the accurate quantification of Leuconostoc mesenteroides.     

Detection of Lactobacillus, Pediococcus, Leuconostoc, and Weissella species in human feces by using group-specific PCR primers and denaturing gradient gel electrophoresis

Denaturing gradient gel electrophoresis (DGGE) of DNA fragments generated by PCR with 16S ribosomal DNA-targeted group-specific primers was used to detect lactic acid bacteria (LAB) of the genera Lactobacillus, Pediococcus, Leuconostoc, and Weissella in human feces. Analysis of fecal samples of four subjects revealed individual profiles of DNA fragments originating not only from species that have been described as intestinal inhabitants but also from characteristically food-associated bacteria such as Lactobacillus sakei, Lactobacillus curvatus, Leuconostoc mesenteroides, and Pediococcus pentosaceus. Comparison of PCR-DGGE results with those of bacteriological culture showed that the food-associated species could not be cultured from the fecal samples by plating on Rogosa agar. On the other hand, all of the LAB species cultured from feces were detected in the DGGE profile. We also detected changes in the types of LAB present in human feces during consumption of a milk product containing the probiotic strain Lactobacillus rhamnosus DR20. The analysis of fecal samples from two subjects taken before, during, and after administration of the probiotic revealed that L. rhamnosus was detectable by PCR-DGGE during the test period in the feces of both subjects, whereas it was detectable by culture in only one of the subjects.     

Isolation and identification of lactic acid bacteria from soil using an enrichment procedure

AIMS: To survey, and identify and classify the ecological distribution of lactic acid bacteria from soil in Japan and Taiwan. METHODS AND RESULTS: Acid-producing bacteria were isolated from 68 soil samples, collected from Japan and Taiwan, in the rhizospheres of fruit trees, from the floor of a henhouse and around a horse farm. All isolates were identified by physiological and genetic tests. Thirty-two of the 54 isolates were identified as lactic acid bacteria (LAB), 16 as spore-forming lactic acid bacteria, five as Clostridium and one as Bacillus. These lactic acid bacteria represent five genera: Lactobacillus, Lactococcus, Enterococcus, Leuconostoc and Weissella. CONCLUSIONS: A high rate of isolating lactic acid bacteria was obtained from soil. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests that soil may be a common source for the isolation of lactic acid bacteria.     

Value of recN sequences for species identification and as a phylogenetic marker within the family "Leuconostocaceae"

The genera Leuconostoc, Oenococcus, and Weissella (family "Leuconostocaceae") constitute a group of lactic acid bacteria of great interest in food microbiology. From the taxonomic point of view, they are considered phylogenetically coherent according to their 16S rRNA gene sequences and other macromolecules. These three genera were the focus of the present study; specifically, the resolution and discriminatory power of recN (encoding a DNA repair and genetic recombination protein) as a molecular marker at the species level were investigated. For this purpose, partial sequences (about 1200 nt) were obtained from 23 type strains and from several additional strains following direct amplification of recN and subsequent sequencing. Phylogeny was evaluated according to different treeing methods (neighbor joining, maximum likelihood, and maximum parsimony) and the inclusion of variability filters. The results showed that recN, used either alone or in combination with 16S rRNA data, can serve as a phylogenetic marker as well as a tool for species identification.     

The use of multiplex PCR reactions to characterize populations of lactic acid bacteria associated with meat spoilage

A rapid, systematic and reliable approach for identifying lactic acid bacteria associated with meat was developed, allowing for detection of Carnobacterium spp., Lactobacillus curvatus, Lact. sakei and Leuconostoc spp. Polymerase chain reaction primers specific for Carnobacterium and Leuconostoc were created from 16S rRNA oligonucleotide probes and used in combination with species-specific primers for the 16S/23S rRNA spacer region of Lact. curvatus and Lact. sakei in multiplex PCR reactions. The method was used successfully to characterize lactic acid bacteria isolated from a vacuum-packaged pork loin stored at 2 degrees C. Seventy isolates were selected for identification and 52 were determined to be Lact. sakei, while the remaining 18 isolates were identified as Leuconostoc spp.     

A rapid method for identification of typical Leuconostoc species by 16S rDNA PCR-RFLP analysis

A polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method was developed to detect and identify typical Leuconostoc species. This method utilises a set of specific primers for amplification of the 16S rDNA region of typical Leuconostoc species. All Leuconostoc-type strains, all Leuconostoc isolates from kimchi, Korea's traditional, fermented vegetable product, and strains from closely related genera were examined to verify the identification by this method. The primers resulted in amplification only for nine typical Leuconostoc spp., but not for any other genera tested. The size of the amplified products was 976 bp and the amplicons of the different species could be differentiated from each other with MseI, HaeIII and Tsp509I endonucleases, except for the species Leuconostoc argentinum and Leuconostoc lactis, which were indistinguishable. A PCR-RFLP method for the typical Leuconostoc species was optimized to identify a large number of isolates from fermented vegetable product. This PCR-RFLP method enables the rapid and reliable identification of Leuconostoc species and to distinguish them from the other phylogenetically related lactic acid bacteria in food samples.     

青藏高原垂穗披碱草青贮饲料中乳酸菌的多样性及低温发酵菌株的筛选

【目的】探究青藏高原垂穗披碱草青贮饲料中乳酸菌的多样性,筛选在低温条件下(10、15和25°C)生长性能较好的优良菌株。【方法】将垂穗披碱草青贮饲料中分离纯化的乳酸菌进行形态特征观察及16S r RNA基因测序鉴定;用MRS液体培养基在10、15和25°C条件下分离、初筛乳酸菌,选取高吸光度值的菌株作为优势菌株。用绿汁发酵液在10、15和25°C条件下培养测定其p H值,选取低p H值菌株作为优势菌株,并综合MRS培养基筛选结果确定优良菌株。【结果】从不同温度和发酵阶段的垂穗披碱草青贮饲料中共分离得到108个乳酸菌菌株,它们分属于6个属、18个种。其中,清酒乳杆菌LS-24在15°C条件下发酵液p H值显著降低(P0.05),戊糖片球菌PP-63在发酵初期生长速度较快,植物乳杆菌LP-21在15°C条件下发酵液p H值降至3.9且有最大活菌数。【结论】在青藏高原垂穗披碱草青贮饲料中发现的乳酸菌属基本涵盖了前人在常温青贮饲料中发现的所有属,但种数略少;在108株菌中,清酒乳杆菌LS-24、戊糖片球菌PP-63和植物乳杆菌LP-21在低温条件下均表现出较好的繁殖和发酵特性,可作为青贮饲料低温发酵的备选菌株。     

Lactic acid bacteria and yeasts associated with gowé production from sorghum in Bénin

AIMS: To identify the dominant micro-organisms involved in the production of gowé, a fermented beverage, and to select the most appropriate species for starter culture development. METHODS AND RESULTS: Samples of sorghum gowé produced twice at three different production sites were taken at different fermentation times. DNA amplification by internal transcribed spacer-polymerase chain reaction of 288 lactic acid bacteria (LAB) isolates and 16S rRNA gene sequencing of selected strains revealed that the dominant LAB responsible for gowé fermentation were Lactobacillus fermentum, Weissella confusa, Lactobacillus mucosae, Pediococcus acidilactici, Pediococcus pentosaceus and Weissella kimchii. DNA from 200 strains of yeasts was amplified and the D1/D2 domain of the 26S rRNA gene was sequenced for selected isolates, revealing that the yeasts species were Kluyveromyces marxianus, Pichia anomala, Candida krusei and Candida tropicalis. CONCLUSIONS: Gowé processing is characterized by a mixed fermentation dominated by Lact. fermentum, W. confusa and Ped. acidilactici for the LAB and by K. marxianus, P. anomala and C. krusei for the yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY: The diversity of the LAB and yeasts identified offers new opportunities for technology upgrading and products development in gowé production. The identified species can be used as possible starter for a controlled fermentation of gowé.     

Natural populations of lactic acid bacteria associated with silage fermentation as determined by phenotype, 16S ribosomal RNA and recA gene analysis

One hundred and fifty-six strains isolated from corn (Zea mays L.), forage paddy rice (Oryza sativa L.), sorghum (Sorghum bicolor L.) and alfalfa (Medicago sativa L.) silages prepared on dairy farms were screened, of which 110 isolates were considered to be lactic acid bacteria (LAB) according to their Gram-positive and catalase-negative characteristics and, mainly, the lactic acid metabolic products. These isolates were divided into eight groups (A-H) based on the following properties: morphological and biochemical characteristics, γ-aminobutyric acid production capacity, and 16S rRNA gene sequences. They were identified as Weissella cibaria (36.4%), Weissella confusa (9.1%), Leuconostoc citreum (5.3%), Leuconostoc lactis (4.9%), Leuconostoc pseudomesenteroides (8.0%), Lactococcus lactis subsp. lactis (4.5%), Lactobacillus paraplantarum (4.5%) and Lactobacillus plantarum (27.3%). W. cibaria and W. confusa were mainly present in corn silages, and L. plantarum was dominant on sorghum and forage paddy rice silages, while L. pseudomesenteroides, L. plantarum and L. paraplantarum were the dominant species in alfalfa silage. The corn, sorghum and forage paddy rice silages were well preserved with lower pH values and ammonia-N concentrations, but had higher lactic acid content, while the alfalfa silage had relatively poor quality with higher pH values and ammonia-N concentrations, and lower lactic acid content. The present study confirmed the diversity of LAB species inhabiting silages. It showed that the differing natural populations of LAB on these silages might influence fermentation quality. These results will enable future research on the relationship between LAB species and silage fermentation quality, and will enhance the screening of appropriate inoculants aimed at improving such quality.     

Rapid identification of Lactobacillus and Bifidobacterium in probiotic products using multiplex PCR

Lactic acid bacteria (LAB) are beneficial for the gastrointestinal tract and reinforce immunity in human health. Recently, many functional products using the lactic acid bacteria have been developed. Among these LAB, Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium longum, and Bifidobacterium bifidum are frequently used for probiotic products. In order to monitor these LAB in commercial probiotic products, a multiplex PCR method was developed. We designed four species-specific primer pairs for multiplex PCR from the 16S rRNA, 16S-23S rRNA intergenic spacer region, and 23S rRNA genes in Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium longum, and Bifidobacterium bifidum. Using these primer pairs, 4 different LAB were detected with high specificity in functional foods. We suggest that the multiplex PCR method developed in this study would be an efficient tool for simple, rapid, and reliable identification of LAB used as probiotic strains.     

Identification and characterization of lactic acid bacteria isolated from traditional pickles in Sichuan, China

The pickle, a traditional fermented vegetable product, is popular in Sichuan Province of China. The objective of this study was to investigate the diversity of dominant lactic acid bacteria (LAB) in pickles by analyzing 36 samples collected from 6 different regions in Sichuan Province. The LAB counts in these samples varied from 3.90 to 8.40 log cfu ml^-1. In total, 185 presumptive LAB with Gram-positive and catalase-negative properties were obtained from these samples using MRS agar, and those strains were identified at the species level by physiological tests, 16S rRNA gene sequencing and multiplex PCR assay. The results revealed that all isolates were accurately identified as Enterococcus thailandicus (2 strains), Lactobacillus alimentarius (16 strains), L. brevis (24 strains), L. paracasei (9 strains), L. plantarum (81 strains), L. pentosus (38 strains), L. sakei (8 strains), L. spicheri (1 strain), Leuconostoc lactis (1 strain) and Pediococcus ethanolidurans (5 strains). The predominant LAB in Sichuan pickle was L. plantarum, which were isolated from most samples. The results also demonstrated that different regions in Sichuan Province have complex compositions of LAB species, and such a rich resource of LAB strains provides raw data for further studies involving probiotic strain selection.     

Isolation and identification of lactic acid bacteria from Tarag in Eastern Inner Mongolia of China by 16S rRNA sequences and DGGE analysis

Tarag is a characteristic fermented dairy product with rich microflora (especially lactic acid bacteria), developed by the people of Mongolian nationality in Inner Mongolia of China and Mongolia throughout history. One hundred and ninety-eight samples of Tarag were collected from scattered households in Eastern Inner Mongolia, and total of 790 isolates of lactic acid bacteria (LAB) were isolated by traditional pure culture method. To identify these isolates and analyze their biodiversity, 16S rRNA gene sequences analysis and PCR-DGGE were performed respectively. The results showed that 790 isolates could be classified as 31 species and subspecies. Among these isolates, Lactobacillus helveticus (153 strains, about 19.4%), Lactococcus lactis subsp. lactis (132 strains, about 16.7%) and Lactobacillus casei (106 strains, about 11.0%) were considered as the predominated species in the traditional fermented dairy products (Tarag) in Eastern Inner Mongolia. It was shown that the biodiversity of LAB in Tarag in Inner Mongolia was very abundant, and this traditional fermented dairy product could be considered as valuable resources for LAB isolation and probiotic selection.     

Antifungal activity of strains of lactic acid bacteria isolated from a semolina ecosystem against Penicillium roqueforti, Aspergillus niger and Endomyces fibuliger contaminating bakery products

Thirty samples of Italian durum wheat semolina and whole durum wheat semolina, generally used for the production of Southern Italy's traditional breads, were subjected to microbiological analysis in order to explore their lactic acid bacteria (LAB) diversity and to find strains with antifungal activity. A total of 125 presumptive LAB isolates (Gram-positive and catalase-negative) were characterized by repetitive extragenic palindromic-PCR (REP-PCR) and sequence analysis of the 16S rRNA gene, leading to the identification of the following species: Weissella confusa, Weissella cibaria, Leuconostoc citreum, Leuconostoc mesenteroides, Lactococcus lactis, Lactobacillus rossiae and Lactobacillus plantarum. The REP-PCR results delineated 17 different patterns whose cluster analysis clearly differentiated W. cibaria from W. confusa isolates. Seventeen strains, each characterized by a different REP-PCR pattern, were screened for their antifungal properties. They were grown in a flour-based medium, comparable to a real food system, and the resulting fermentation products (FPs) were tested against fungal species generally contaminating bakery products, Aspergillus niger, Penicillium roqueforti and Endomyces fibuliger. The results of the study indicated a strong inhibitory activity – comparable to that obtained with the common preservative calcium propionate (0.3% w/v) – of ten LAB strains against the most widespread contaminant of bakery products, P. roqueforti. The screening also highlighted the unexplored antifungal activity of L. citreum, L. rossiae and W. cibaria (1 strain), which inhibited all fungal strains to the same or a higher extent compared with calcium propionate. The fermentation products of these three strains were characterized by low pH values, and a high content of lactic and acetic acids.