Biocontrol of Listeria monocytogenes by lactic acid bacteria isolated from brewer's grains used as feedstuff in Argentina

2015 ◽  
Vol 61 ◽  
pp. 27-31 ◽  
Author(s):  
P. Asurmendi ◽  
M.J. García ◽  
L. Pascual ◽  
L. Barberis
2020 ◽  
Vol 65 (No. 1) ◽  
pp. 23-30 ◽  
Author(s):  
Heping Zhao ◽  
Feike Zhang ◽  
Jun Chai ◽  
Jianping Wang

The present study aimed to investigate the effect of probiotic lactic acid bacteria (LAB) addition on Listeria monocytogenes translocation and its toxin listeriolysin O (LLO), proinflammatory factors, immune organ indexes and serum immunoglobulins in farmed rabbits. Five treatments included negative control (NC), positive control (PC) with L. monocytogenes infection and supplemental LAB at 3.0 × 10<sup>6 </sup>(low-LAB, L-LAB), 3.0 × 10<sup>8</sup> (medium-LAB, M-LAB) and 3.0 × 10<sup>10 </sup>(high-LAB, H-LAB) CFU/kg of diet, respectively. The LAB was a mixture of equal amounts of Lactobacillus acidophilus (ACCC11073), Lactobacillus plantarum (CICC21863) and Enterococcus faecium (CICC20430). A total of 180 weaned rabbits (negative for L. monocytogenes) were randomly assigned to 5 groups with 6 replicates of 6 rabbits each in response to the 5 treatments. L. monocytogenes infection occurred on the first day of feeding trial and dietary LAB supplementation lasted for 14 days. The results showed that on days 7 and 14 post administration, L. monocytogenes in caecum, liver, spleen and lymph nodes was reduced in M-LAB and H-LAB compared to PC (P &lt; 0.05), and linear and quadratic reducing trends were found in liver on day 7 (P ≤ 0.002). On day 14, mucosa LLO mRNA expression and serum TNFα, IL1β and IFNγ were reduced in the three LAB treatments (P &lt; 0.05), and linear and quadratic trends were found on TNFα and IL1β (P ≤ 0.025); indexes of thymus and spleen, serum IgA and IgG were increased in the LAB treatments (P &lt; 0.05). It is concluded that LAB can be used to alleviate L. monocytogenes infection and to improve the immune function of farmed animals.


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.


2007 ◽  
Vol 70 (11) ◽  
pp. 2485-2497 ◽  
Author(s):  
OLE MEJLHOLM ◽  
PAW DALGAARD

A cardinal parameter model was developed to predict the effect of diacetate, lactate, CO2, smoke components (phenol), pH, NaCl, temperature, and the interactions between all parameters on the growth of lactic acid bacteria (LAB) in lightly preserved seafood. A product-oriented approach based on careful chemical characterization and growth of bacteria in ready-to-eat seafoods was used to develop this new LAB growth model. Initially, cardinal parameter values for the inhibiting effect of diacetate, lactate, CO2, pH, and NaCl–water activity were determined experimentally for a mixture of LAB isolates or were obtained from the literature. Next, these values and a cardinal parameter model were used to model the effect of temperature (Tmin) and smoke components (Pmax). The cardinal parameter model was fitted to data for growth of LAB (μmax values) in lightly preserved seafood including cold-smoked and marinated products with different concentrations of naturally occurring and added organic acids. Separate product validation studies of the LAB model resulted in average bias and accuracy factor values of 1.2 and 1.5, respectively, for growth of LAB (μmax values) in lightly preserved seafood. Interaction between LAB and Listeria monocytogenes was predicted by combining the developed LAB model and an existing growth and growth boundary model for the pathogen (O. Mejlholm and P. Dalgaard, J. Food Prot. 70:70–84). The performance of the existing L. monocytogenes model was improved by taking into account the effect of microbial interaction with LAB. The observed and predicted maximum population densities of L. monocytogenes in inoculated lightly preserved seafoods were 4.7 and 4.1 log CFU g−1, respectively, whereas for naturally contaminated vacuum-packed cold-smoked salmon the corresponding values were 0.7 and 0.6 log CFU g−1 when a relative lag time of 4.5 was used for the pathogen.


2004 ◽  
Vol 67 (12) ◽  
pp. 2703-2711 ◽  
Author(s):  
KONSTANTINOS P. KOUTSOUMANIS ◽  
LAURA V. ASHTON ◽  
IFIGENIA GEORNARAS ◽  
KEITH E. BELK ◽  
JOHN A. SCANGA ◽  
...  

The survival and growth of Listeria monocytogenes and spoilage microflora during storage of fresh beef subjected to different decontamination treatments was studied. Fresh beef inoculated with a five-strain mixture of L. monocytogenes (5.18 log CFU/cm2) was left untreated (control) or was immersed (30 s) in hot water (HW; 75°C), 2% lactic acid (LA; 55°C), hot water followed by lactic acid (HW-LA), or lactic acid followed by hot water (LA-HW) and then stored aerobically at 4, 10, and 25°C for 25, 17, and 5 days, respectively. Initial populations of L. monocytogenes were reduced by 0.82 (HW), 1.43 (LA), 2.73 (HW-LA), and 2.68 (LA-HW) log CFU/cm2. During storage, the pathogen grew at higher rates in HW than in control samples at all storage temperatures. Acid decontamination treatments (LA, HW-LA, and LA-HW) resulted in a weaker inhibition of L. monocytogenes (P &lt; 0.05) at 25°C than at 4 and 10°C. In general, the order of effectiveness of treatments was HW-LA &gt; LA &gt; LA-HW &gt; HW &gt; control at all storage temperatures tested. In untreated samples, the spoilage microflora was dominated by pseudomonads, while lactic acid bacteria, Enterobacteriaceae, and yeasts remained at lower concentrations during storage. Brochothrix thermosphacta was detected periodically in only a limited number of samples. Although decontamination with HW did not affect the above spoilage microbial profile, acid treatments shifted the predominant microflora in the direction of yeasts and gram-positive bacteria (lactic acid bacteria). Overall, the results of the present study indicate that decontamination with LA and combinations of LA and HW could limit growth of L. monocytogenes and inhibit pseudomonads, which are the main spoilage bacteria of fresh beef stored under aerobic conditions. However, to optimize the efficacy of such treatments, they must be applied in the appropriate sequence and followed by effective temperature control.


1990 ◽  
Vol 53 (8) ◽  
pp. 642-647 ◽  
Author(s):  
CURTT M. PERRY ◽  
CATHERINE W. DONNELLY

Silage samples representing approximately 10% of Vermont's dairy farms were tested for the presence of Listeria species. Listeria innocua was isolated from 15.3% of the silage samples, while Listeria monocytogenes was isolated from 2.9% of the examined samples. As silage pH increased, the incidence of Listeria increased concomitantly. Seventy-eight mesophilic lactic acid bacteria, indigenous to silage, were screened for specific and nonspecific antagonism against four L. monocytogenes indicator strains. Most of the silage isolates demonstrated nonspecific inhibition via lactic acid production against the L. monocytogenes indicator strains. None of the indigenous silage isolates tested in this survey demonstrated specific antagonism via production of bacteriocinogenic compounds.


2005 ◽  
Vol 68 (11) ◽  
pp. 2356-2361 ◽  
Author(s):  
JIN KYUNG KIM ◽  
ELAINE M. D'SA ◽  
MARK A. HARRISON ◽  
JUDY A. HARRISON ◽  
ELIZABETH L. ANDRESS

Listeria monocytogenes can survive and grow in refrigerated foods with pH values of approximately 4.0 to 5.0 and salt concentrations of 3 to 4%. Home-fermented refrigerator dill pickles fit this description. Contamination of this product with L. monocytogenes could cause serious problems because these items are not heated prior to consumption. L. monocytogenes survival and growth patterns were investigated in refrigerator dill pickles at 1.3, 3.8, and 7.6% salt concentrations. Pickling cucumbers were dipped into an inoculum of L. monocytogenes, brine mixtures were added, and cucumbers were held at room temperature for 1 week and then refrigerated for up to 3 months. The pH, NaCl percentage, titratable acidity percentage, and total populations of Listeria and aerobic, psychrotrophic, and lactic acid bacteria were measured at the addition of brine, after 2, 4, and 7 days of storage at room temperature, and then weekly during refrigerated storage. The initial Listeria population was 5.4 to 5.6 log CFU/cm2 on cucumber surfaces and 3.9 to 4.6 log CFU/g internally. There was an approximate 0.3- to 1-log increase during room temperature fermentation followed by a population decline during refrigerator storage, with a greater decrease in the brines with the highest NaCl concentration. Up to 49 days, the internal tissue of pickles with 1.3, 3.8, or 7.6% salt concentrations were presumptively positive for L. monocytogenes by the enrichment method, and at 91 days the surfaces of such pickles were still positive for L. monocytogenes. Populations of total aerobes and lactic acid bacteria increased during room temperature storage and decreased gradually during refrigerated storage.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Nathália Parma Augusto Castilho ◽  
Monique Colombo ◽  
Leandro Licursi de Oliveira ◽  
Svetoslav Dimitrov Todorov ◽  
Luís Augusto Nero

2019 ◽  
Vol 8 (3) ◽  
Author(s):  
Erica Tirloni ◽  
Vanessa Di Pietro ◽  
Giuseppe Rizzi ◽  
Francesco Pomilio ◽  
Patrizia Cattaneo ◽  
...  

Aim of the present study was the evaluation of the growth potential of Listeria spp. inoculated in the typical North Italian dry fermented sausage “Bergamasco” salami during its production. As it was necessary to carry out the challenge test in the production line of the industry, according to the guidelines of the European Reference Laboratory for Listeria monocytogenes, a non-pathogenic “surrogate” microorganism was used: for the inoculum, two strains of Listeria innocua (1 ATCC, 1 strain isolated from a similar substrate) were used. The inoculation of the samples occurred during grinding and mixing of the sausage mass, before the filling. To avoid cross-contamination, the control samples were produced before the contaminated ones. After the dripping, salamis were subjected to the normal production process (drying and maturation in five steps at specific temperatures and humidity rates). The inoculated products were subjected to the enumeration of Listeria spp. at T0 (day of inoculation) and at T4 (post-drying), and every 10 days during curing (T10, T20, T30, T40, T50, T60, T70, T80 and T90), as this salami is generally sold as whole piece with varying levels of curing (from T20 to T90). Since the product may be cut in half and vacuumpacked, at each of the times starting from T20, half salami was vacuum-packed and stored for 30 days at 12°C, at the end of the which Listeria spp. enumeration was performed again. At all times and for each type of samples of each of the three batches, the enumeration of the natural microflora (Total Viable Count, lactic acid bacteria, Pseudomonas spp., Enterobacteriaceae) and the determination of water activity and pH were performed on control samples. The product was characterized by a high concentration of microflora (8-8.5 Log UFC/g), consisting mainly of lactic acid bacteria, added to the mixture at the beginning of the production process. The pH showed a decrease over time, expected for this type of products, due to the development of lactic acid bacteria (final pH: 5.42-5.55). The water activity reached values able to inhibit the development of Listeria spp. (final aw: 0.826-0.863). Listeria counts in the tested batches of “Bergamasco” salami showed the absence of significant growth in the product with a reduction of loads if compared to T0, between -0.59 and -1.04 Log CFU/g. Even in the samples subjected to vacuum packaging and storage at 12°C, the absence of significant increase of lactic acid bacteria in the product was highlighted with further decrease of bacterial loads (-0.70/-0.79 Log CFU/g if compared to T20). Considering the worst case scenario (thus the batch with the highest growth potential), in the products stored in the curing room at 14-16°C, at humidity of 80% and in the samples stored at 12°C and vacuum packaged, the threshold indicated by the EURL Lm guidelines (+0.5 Log CFU/g) for the growth of Listeria spp. was not reached, allowing to classify “Bergamasco” salami in the category 1.3 of the EC Reg. 2073/2005 as “Ready-to-eat food unable to support the growth of Listeria monocytogenes”.


2008 ◽  
Vol 71 (3) ◽  
pp. 629-633 ◽  
Author(s):  
K. M. GAILUNAS ◽  
K. E. MATAK ◽  
R. R. BOYER ◽  
C. Z. ALVARADO ◽  
R. C. WILLIAMS ◽  
...  

Ready-to-eat meat products have been implicated in several foodborne listeriosis outbreaks. Microbial contamination of these products can occur after thermal processing when products are chilled in salt brines. The objective of this study was to evaluate UV radiation on the inactivation of Listeria monocytogenes and lactic acid bacteria in a model brine chiller system. Two concentrations of brine (7.9% [wt/wt] or 13.2% [wt/wt]) were inoculated with a ~6.0 log CFU/ml cocktail of L. monocytogenes or lactic acid bacteria and passed through a UV treatment system for 60 min. Three replications of each bacteria-and-brine combination were performed and resulted in at least a 4.5-log reduction in microbial numbers in all treated brines after exposure to UV light. Bacterial populations were significantly reduced after 5 min of exposure to UV light in the model brine chiller compared with the control, which received no UV light exposure (P &lt; 0.05). The maximum rate of inactivation for both microorganisms in treated brines occurred between minutes 1 and 15 of UV exposure. Results indicate that in-line treatment of chill brines with UV light reduces the number of L. monocytogenes and lactic acid bacteria.


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