Behaviour of Listeria monocytogenes during the maturation of naturally and artificially contaminated salami: effect of lactic-acid bacteria starter cultures

1993 ◽  
Vol 20 (3) ◽  
pp. 169-175 ◽  
Author(s):  
Mirella Campanini ◽  
Ilaria Pedrazzoni ◽  
Silvana Barbuti ◽  
P. Baldini
1988 ◽  
Vol 51 (8) ◽  
pp. 600-606 ◽  
Author(s):  
MICHELLE M. SCHAACK ◽  
ELMER H. MARTH

The ability of Listeria monocytogenes to grow and compete with mesophilic lactic acid bacteria was examined. Autoclaved skim milk was inoculated with 103 cells of L. monocytogenes (strain V7 or Ohio)/ml, and with 5.0, 1.0, 0.5 or 0.1% of a milk culture of either Streptococcus cremoris or Streptococcus lactis. Inoculated milks were fermented for 15 h at 21 or 30°C, followed by refrigeration at 4°C. Samples were plated on McBride Listeria Agar to enumerate L. monocytogenes and on either APT Agar or plate count agar to enumerate lactic acid bacteria. L. monocytogenes survived in all fermentations, and commonly also grew to some extent. Incubation at 30°C with 5% S. lactis as inoculum appeared to be the most inhibitory combination for strain V7, causing 100% inhibition in growth based on maximum population attained. S. cremoris at the 5.0% and 0.1% inoculum levels, was slightly less inhibitory to L. monocytogenes at 37°C, but it was slightly more inhibitory to L. monocytogenes at the 1.0% inoculum level than was S. lactis. In general, S. lactis reduced the pH of fermented milks more than did S. cremoris. The population of L. monocytogenes began to decrease before 15 h in only one test combination, which was use of a 5.0% inoculum of S. cremoris and 30°C incubation. In most instances, growth of the pathogen appeared to be completely inhibited when the pH dropped below 4.75.


2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Giusi Macaluso ◽  
Gerlando Fiorenza ◽  
Raimondo Gaglio ◽  
Isabella Mancuso ◽  
Maria Luisa Scatassa

Bacteriocins are antimicrobial proteins produced by bacteria that inhibit with a bactericidal or bacteriostatic mode of action, the growth of other bacteria. Many lactic acid bacteria (LAB) produce a high diversity of different bacteriocins. Bacteriocinogenic LAB are generally recognized as safe (GRAS) and useful to control the frequent development of pathogens and spoilage microorganisms; for this reason they are commonly used as starter cultures in food fermentations. In this study, the authors describe the results of a screening on 699 LAB isolated from wooden vat surfaces, raw milk and traditional Sicilian cheeses, for the production of bacteriocin-like inhibitory substances (BLIS), by comparing two alternative methods. The antagonistic activity of LAB and its proteinaceous nature were evaluated using the <em>spot on the lawn</em> and the <em>well-diffusion assay</em> and the sensitivity to proteolytic (proteinase K, protease B and trypsin), amylolytic (α-amylase) and lipolytic (lipase) enzymes. The indicator strains used were: <em>Listeria monocytogenes</em>, <em>Staphylococcus aureus</em>, <em>E. coli</em>, <em>Salmonella enteritidis</em>. A total of 223 strains (belonged to the species <em>Enterococcus</em> spp., <em>Lactobacillus</em> spp., <em>Pediococcus</em> spp., <em>Streptococcus</em> spp., <em>Leuconostoc</em> spp. and <em>Lactococcus lactis</em>) were found to inhibit the growth of <em>Listeria monocytogenes</em> by using the <em>spot on the lawn</em> method; only 37 of these were confirmed by using the well-diffusion assay. The direct addition of bacteriocin-producing cultures into dairy products can be a more practical and economic option for the improvement of the safety and quality of the final product.


2014 ◽  
Vol 32 (No. 2) ◽  
pp. 145-151 ◽  
Author(s):  
I. Složilová ◽  
S. Purkrtová ◽  
M. Kosová ◽  
M. Mihulová ◽  
E. Šviráková ◽  
...  

Eight individual bacteriocin-producing lactic acid bacteria (LAB) strains and three bacteriocin-non-producing cheese starter cultures were evaluated for their ability to inhibit the growth of six Listeria monocytogenes strains, originating from the guinea-pig lymph nodes, raw cow milk, and manufacturing dairy equipment. Results showed that either live cells or cell-free neutralised supernatant (CFNS) and/or heated CFNS of six individual LAB strains (Lcc. lactis subsp. lactis CCDM 416 and NIZO R5, Lbc. plantarum HV 11 and DC 1246, P. acidilactici HV 12, and Ent. mundtii CCM 1282) and one starter culture (DELVO-ADD<sup>&reg;</sup> 100-X DSF) were effective in the suppression of at least one listeria strain. Neither any individual LAB strain nor starter culture was antagonistic toward all studied L. monocytogenes strains, indicating diverse sensitivity/resistance among L. monocytogenes strains to antimicrobial compounds of LAB. The significant susceptibility of listerias isolated from raw milk and dairy equipment together with the strong antilisterial activity of DELVO-ADD<sup>&reg; </sup>100-X DSF could be applied in dairy technology, where commonly used starter cultures could play both the biopreservative and fermentation role. &nbsp;


2004 ◽  
Vol 67 (10) ◽  
pp. 2189-2194 ◽  
Author(s):  
CINZIA CAGGIA ◽  
CINZIA L. RANDAZZO ◽  
MONIA DI SALVO ◽  
FLORA ROMEO ◽  
PAOLO GIUDICI

Microbiological safety of green table olives from different cultivars, prepared by both the Spanish-style and biological methods and fermented with starter cultures of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus casei, and Lactobacillus pentosus), was investigated. The fermentation process was monitored by measuring pH values, titratable acidities, and growth of lactic acid bacteria over time. During fermentation, lactic acid bacteria and yeasts were major microbial populations. Microbiological safety was evaluated by analysis for Listeria monocytogenes with the use of an enrichment method during storage (from 55 days to 18 months). Results demonstrated that L. monocytogenes can survive and grow in green table olives. L. monocytogenes was found in one of the commercial (thermally treated) samples analyzed and in all samples older than 2 months, irrespective of olive cultivar, lactic acid bacteria starter used, pH and titratable acidity of brine samples, or treatment applied.


2015 ◽  
Vol 6 (3) ◽  
pp. 337-343 ◽  
Author(s):  
M. Garriga ◽  
R. Rubio ◽  
T. Aymerich ◽  
P. Ruas-Madiedo

The capability of five lactic acid bacteria (LAB) to counteract the adhesion of Listeria monocytogenes to the epithelial intestinal cell line HT29 was studied. The highest adhesion ability to HT29 was achieved by the intestinal strain Lactobacillus rhamnosus CTC1679, followed by the meat-derived strains Lactobacillus sakei CTC494 and Enterococcus faecium CTC8005. Surprisingly, the meat strains showed significantly better adhesion to HT29 than two faecal isolates of Lactobacillus casei and even significantly higher than the reference strain L. rhamnosus GG. Additionally, the anti-listerial, bacteriocin-producer starter culture L. sakei CTC494 was able to significantly reduce the adhesion of L. monocytogenes to HT29 in experiments of exclusion, competition and inhibition. The performance was better than the faecal isolate L. rhamnosus CTC1679. Our results reinforce the fact that the ability of LAB to interact with a host epithelium model, as well as to antagonise with foodborne pathogens, is a strain-specific characteristic. Additionally, it is underlined that this trait is not dependent on the origin of the bacterium, since some food LAB behave better than intestinal ones. Therefore, the search for novel strains in food niches is a suitable approach to find those with potential health benefits. These strains are likely pre-adapted to the food environment, which would make their inclusion in the formulation of probiotic foods more feasible.


Author(s):  
P THONART ◽  
P KOUAKOU ◽  
Dora I COULIBALY ◽  
A YAO ◽  
H GHALFI ◽  
...  

Lactic acid bacteria isolated by screening method from traditional food products of African countries were tested for their ability to produce bacteriocin an antimicrobial substances acting against other bacteria. Some of these bacteriocins allow the inhibition of Listeria monocytogenes, a food-bome pathogen responsible for human listeriosis. However, food ingredients caused an inefficient action of bacteriocins produced by several lactic acid bacteria against Listeria monocytogenes achieving the phenomenon of Listeria growth rebound in bacteriocin-supplemented food models. Recently, new starter cultures of lactic acid bacteria with an industrially important functionality are being developed. The latter can contribute to inhibit the rebounding phenomenon of Listeria and offer one or more organoleptic, technological, nutritional, or health advantages.


2000 ◽  
Vol 63 (7) ◽  
pp. 916-920 ◽  
Author(s):  
WAYNE M. PITT ◽  
TERENCE J. HARDEN ◽  
RON R. HULL

The behavior of Listeria monocytogenes in pasteurized milk during fermentation with starter and nonstarter lactic acid bacteria was investigated. Pasteurized milk was co-inoculated with approximately 104 CFU/ml of L. monocytogenes and 106 CFU/ml of Lactococcus lactis, Lactococcus cremoris, Lactobacillus plantarum, Lactobacillus bulgaricus, or Streptococcus thermophilus. Inoculated milks were incubated at 30°C or 37°C for 24 to 72 h. Listeria monocytogenes survived and also grew to some extent during incubation in the presence of all starter cultures; however, inhibition ranged from 83 to 100% based on maximum cell populations. During incubation with L. bulgaricus and L. plantarum, L. monocytogenes was completely inactivated after 20 h and 64 h of incubation at 37°C and 30°C, respectively. The pH of the fermenting milks declined steadily throughout the fermentation periods and was approximately 4.2 at the conclusion of the experimental period regardless both of the starter culture and pathogen combination or the temperature of incubation.


2020 ◽  
Vol 29 (12) ◽  
pp. 59-63
Author(s):  
O.I. Parakhina ◽  
◽  
M.N. Lokachuk ◽  
L.I. Kuznetsova ◽  
E.N. Pavlovskaya ◽  
...  

The research was carried out within the framework of the theme of state assignment № 0593–2019–0008 «To develop theoretical foundations for creating composite mixtures for bakery products using physical methods of exposure that ensure homogeneity, stability of mixtures and bioavailability of nutrients, to optimize diets population of Russia». The data on the species belonging of new strains of lactic acid bacteria and yeast isolated from samples of good quality gluten-free starter cultures are presented. A comparative assessment of the antagonistic and acid-forming activity of strains of lactic acid bacteria and the fermentative activity of yeast was carried out. The composition of microbial compositions from selected strains of LAB and yeast was developed. The influence of the starter culture on the new microbial composition on the physicochemical, organoleptic indicators of the bread quality and resistance to mold and ropy-disease was investigated.


2021 ◽  
pp. 1-7
Author(s):  
Harutoshi Tsuda ◽  
Kana Kodama

Abstract This paper reveals the technological properties of lactic acid bacteria isolated from raw milk (colostrum and mature milk) of Wagyu cattle raised in Okayama Prefecture, Japan. Isolates were identified based on their physiological and biochemical characteristics as well as 16S rDNA sequence analysis. Streptococcus lutetiensis and Lactobacillus plantarum showed high acid and diacetyl-acetoin production in milk after 24 h of incubation at 40 and 30°C, respectively. These strains are thought to have potential for use as starter cultures and adjunct cultures for fermented dairy products.


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