Assessment of Coagulase-Negative Staphylococci and Lactic Acid Bacteria Isolated from Portuguese Dry Fermented Sausages as Potential Starters Based on Their Biogenic Amine Profile (original) (raw)
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Journal of Applied Microbiology, 2006
Aim: To evaluate the biodiversity of lactobacilli from slightly fermented sausages (chorizo, fuet and salchichon) by molecular typing, while considering their safety aspects.Methods and Results: Species-specific PCR, plasmid profiling and randomly amplified polymorphic DNA (RAPD)-PCR were used to characterize 250 lactic acid bacteria (LAB) isolated from 21 low acid Spanish fermented sausages. Lactobacillus sakei was the predominant species (74%) followed by Lactobacillus curvatus (21·2%) and Leuconostoc mesenteroides (4·8%). By plasmid profiling and RAPD-PCR 144 different strains could be differentiated, 112 belonging to Lact. sakei, 23 to Lact. curvatus and 9 to Leuc. mesenteroides. Ion-pair high performance liquid chromatography was used to detect biogenic amine production. Tyramine and phenylethylamine were produced by 14·4 and 12·4% of the isolates, respectively, all belonging to the species Lact. curvatus. The production of tyramine was stronger than that of phenylethylamine. Partial sequencing of the tyrosine decarboxylase gene from Lact. curvatus was achieved. A specific PCR assay to detect the Lact. curvatus tyramine-producers was designed. The disc diffusion test was used to detect antibiotic resistance among the isolates. Most isolates displayed resistance to vancomycin and gentamicin. Only four strains were resistant to most of the antibiotics tested. None of the isolates were resistant to erythromycin.Conclusions: Lactobacillus sakei would be the species of choice for further use as starter culture in fermented sausage production. Strain typing and characterization of biogenic amine production together with antibiotic susceptibility testing for the selection of starter cultures could help to increase the quality and safety of the products.Significance and Impact of the Study: Species-specific PCR, RAPD and plasmid profiling proved to be efficient at typing LAB at species and strain level. Information on biogenic amine production and transferable antibiotic resistance is important in order to avoid selection of strains with undesirable properties as starter cultures.
Evaluation of Functional Aspects in Lactobacillus Strains Isolated from Dry Fermented Sausages
Journal of Food Quality, 2007
The aim of this study was to characterize lactobacilli isolated from a traditional Italian dry-fermented sausages inoculated with Lactobacillus casei/paracasei for use as probiotics. Strains isolated were L. casei (38%), L. paracasei paracasei (32%), Lactobacillus rhamnosus (21%) and Lactobacillus sakei sakei (9%). L. paracasei paracasei and L. rhamnosus showed no significant decrease in viability compared with L. casei and L. sakei sakei in artificial gastric juice; L. casei and L. sakei sakei were not affected by artificial intestinal fluid. In human embryonic intestine cell line (INT407) in vitro model, L. rhamnosus and L. sakei sakei were more adhesive than the other strains. The production of acetic acid (40.92 Ϯ 1.94 mmol/L) and propionic acid (0.14 Ϯ 0.07 mmol/L) was similar in all strains tested. Considerably higher (100-250 mmol/L) levels of lactic acid were produced by L. casei, L. paracasei paracasei and L. rhamnosus, and were varied depending on microaerobic or anaerobic conditions. L. casei and L. rhamnosus had the best antibacterial activity against Escherichia coli and Salmonella enterica ssp. enterica (serovar Typhimurium). These findings suggest that L. casei and L. rhamnosus merit further investigation as novel starter cultures in meat products.
Meat Science, 2009
A total of 17 strains of Lactobacillus plantarum, isolated from a Tunisian traditional salted meat and identified by biochemical and molecular methods, were characterized according to their technological properties including acidifying, antimicrobial and enzymatic activities as well as antibiotic resistance in order to select the most suitable for use as starter cultures for the production of fermented sausages. All the strains studied showed good acidifying activity and were able to reduce the pH to less than 4.3 in 72, 48 and 24 h at 15, 25 and 37°C respectively. The majority of strains displayed antimicrobial activities against Salmonella arizonae, Staphylococcus aureus, Pseudomonas aeuroginosa and Escherichia coli, however characterization of the antimicrobial substances showed that none of the strains could produce bacteriocins. All the L. plantarum strains were able to hydrolyze casein, whereas none of them was found to possess lipolytic activity. The majority of strains of L. plantarum were resistant to tetracycline, erythromycin, rifampicin, ampicillin and penicillin G.
Brazilian Journal of Microbiology, 2007
The purpose of the present work was to characterize promising starter culture strains of Lactobacillus plantarum isolated from naturally fermented artisanal sausage manufactured in the northwestern region of Rio Grande do Sul state, Brazil. From 127 isolates of homofermentative, Gram-positive and catalase-negative lactic acid bacteria, ten isolates were randomly selected and the phenotypic characterization and speciesspecific PCR were performed. Genomic DNA from each isolated strain and from the reference strains L. plantarum ATCC 8014 and L. pentosus ATCC 8041 were amplified using two pairs of L. plantarum speciesspecific primers (16/Lpl and LbP11/LbP12). The results of the phenotypic characterization and speciesspecific PCR indicated that five out of ten isolates were Lactobacillus plantarum.
El-Tahra Mohamed Ahmed Ammar , 2018
Adjunct cultures are non-starter microorganisms contributing to the development of favorable flavor and texture during cheese ripening. The present study was designed to isolate and characterize potential adjunct cultures of lactic acid bacteria (LAB) from pickled Domiatti cheese and Ras cheese. Fifty-four cheese samples including 33 and 21 samples of pickled Domiatti cheese and Ras cheese, respectively were randomly collected from Mansoura city and villages in its vicinity and assessed for their flavor by panelists. Given the association of the adjunct cultures with typical flavor in cheese, cheese samples with "good" or "acceptable" flavor were further analyzed as a potential source of adjunct LAB cultures. A total of 162 suspected LAB isolates could be recovered from theses samples, of which 37 and 4 isolates were confirmed to belong to the Enterococcus and Lactobacillus genera, respectively. Further biochemical identification to the species level showed that the Enterococcus isolates involved Ent. faecalis (2 isolates), Ent. faecium (7 isolates), Ent. gallinarum (2 isolates), Ent. durans (1 isolate), Ent. mundtii (2 isolates), Ent. casseiliflavus (2 isolates), Ent. pseudoaavium (12 isolates), and Enterococcus spp. (9 isolates). Whereas, Lactobacillus isolates could be identified as Lb. plantarum (1 isolate) and Lactobacillus spp. (3 isolates). Enterococcus and Lactobacillus isolates were examined for technological properties including acidity development, proteolytic activity, and lipolytic activity. They showed phenotypic diversity in those technological characteristics. Isolates were also assessed for safety-associated traits including antibiotic resistance, biogenic amine production, and hemolytic activity. Enterococcus isolates showed resistance to several antibiotics and were able to produce the biogenic amines histamine and tyramine. Hemolytic activity could be also detected in those isolates. Lactobacillus cultures showed resistance to only 2 out of 9 antibiotics and were unable to produce histamine or tyramine. They did not also show hemolytic activity. This study presents a collection of Enterococcus and Lactobacillus isolates to be assessed for use as adjunct cultures based on their technological and safety-related traits.
Food Microbiology, 2007
The physicochemical and microbiological characteristics of spontaneously fermented sausages made by two medium-sized enterprises (MSE) located in southern Greece have been studied. A total of 300 lactic acid bacteria and 300 staphylococcal strains have been isolated and identified by their physiological characteristics. Lactobacillus plantarum strains were found to dominate the lactic acid bacteria microbiota in most of the cases with L. sakei strains prevailing in some of them and L. rhamnosus strains occasionally accompanying the dominant lactic acid bacteria microbiota. On the other hand, S. saprophyticus strains were found to dominate the staphylococcal microbiota in all spontaneously fermented sausages with of S. simulans, S. xylosus, S. gallinarum and S. cohnii cohnii strains being sporadically present. Following the identification, an evaluation of their technological properties, namely proteolytic and lipolytic capacities as well as production of biogenic amines and antimicrobial compounds, took place. None of the lactic acid bacteria and staphylococci was found to possess lipolytic activity whereas a total of 6 lactic acid bacteria and 51 staphylococci strains were found to be able to hydrolyse either the sarcoplasic, myofibrillar or both protein fractions. Furthermore, only one L. sakei strain and 185 staphylococci strains were found to possess decarboxylase activity against lysine, tyrosine, ornithine or histidine. Finally none of the staphylococcal microbiota and 3 lactic acid bacteria strains were found to be able to produce antimicrobial compounds of proteinaceous nature against Listeria monocytogenes. r
Microorganisms, 2020
This paper proposes the industrial validation of a functional strain of Lactobacillus plantarum (strain 178). First, acidification in a meat model medium and bioactivity towards Staphylococcus aureus, Salmonella sp., Listeria monocytogenes, and Escherichia coli were assessed; the performances of Lb. plantarum 178 were compared to those of a commercial Lb. sakei and a probiotic Lb. casei. Lb. plantarum 178 inhibited the pathogens and experienced a higher acidification at 15 °C. Lb. casei and Lb. plantarum were used for an industrial fermentation of traditional Italian sausages. The strains assured the correct course of fermentation and inhibited pathogens and enterobacteria. This study represents the scaling up and the validation of a promising strain at industrial level and shows the possibility of performing the fermentation of traditional Italian sausage through functional starter cultures, combining the benefit of a controlled fermentation and possible health benefits.