scholarly journals Effect of UV-C Irradiation and Lactic Acid Application on the Inactivation of Listeria monocytogenes and Lactic Acid Bacteria in Vacuum-Packaged Beef

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1217
Author(s):  
Giannina Brugnini ◽  
Soledad Rodríguez ◽  
Jesica Rodríguez ◽  
Caterina Rufo
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Quadratic Model ◽  
Meat Color ◽  
Minimal Impact ◽  
Log Reduction ◽  
Combined Application ◽  
Meat Samples ◽  
Uv C

The objective of this study was to test the effect of the combined application of lactic acid (0–5%) (LA) and UV-C light (0–330 mJ/cm2) to reduce Listeria monocytogenes and lactic acid bacteria (LAB) on beef without major meat color (L *, a *, b *) change and its impact over time. A two-factor central composite design with five central points and response surface methodology (RSM) were used to optimize LA concentration and UV-C dose using 21 meat pieces (10 g) inoculated with L. monocytogenes (LM100A1). The optimal conditions were analyzed over 8 weeks. A quadratic model was obtained that predicted the L. monocytogenes log reduction in vacuum-packed beef treated with LA and UV-C. The maximum log reduction for L. monocytogenes (1.55 ± 0.41 log CFU/g) and LAB (1.55 ± 1.15 log CFU/g) with minimal impact on meat color was achieved with 2.6% LA and 330 mJ/cm2 UV-C. These conditions impaired L. monocytogenes growth and delayed LAB growth by 2 weeks in vacuum-packed meat samples throughout 8 weeks at 4 °C. This strategy might contribute to improving the safety and shelf life of vacuum-packed beef with a low impact on meat color.

Use of UV Light for the Inactivation of Listeria monocytogenes and Lactic Acid Bacteria Species in Recirculated Chill Brines

2008 ◽  
Vol 71 (3) ◽  
pp. 629-633 ◽  
Author(s):  
K. M. GAILUNAS ◽  
K. E. MATAK ◽  
R. R. BOYER ◽  
C. Z. ALVARADO ◽  
R. C. WILLIAMS ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Thermal Processing ◽  
Uv Light ◽  
Light Exposure ◽  
Meat Products ◽  
Uv Treatment ◽  
Bacterial Populations ◽  
Log Reduction

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 < 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.

Quantifying Nonthermal Inactivation of Listeria monocytogenes in European Fermented Sausages Using Bacteriocinogenic Lactic Acid Bacteria or Their Bacteriocins: A Case Study for Risk Assessment

2006 ◽  
Vol 69 (11) ◽  
pp. 2648-2663 ◽  
Author(s):  
ELEFTHERIOS H. DROSINOS ◽  
MARIOS MATARAGAS ◽  
SLAVICA VESKOVIĆ-MORAČANIN ◽  
JUDIT GASPARIK-REICHARDT ◽  
MIRZA HADŽIOSMANOVIĆ ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Storage Temperature ◽  
Inactivation Kinetics ◽  
Initial Population ◽  
Log Reduction ◽  
Fermented Sausages

Listeria monocytogenes NCTC10527 was examined with respect to its nonthermal inactivation kinetics in fermented sausages from four European countries: Serbia-Montenegro, Hungary, Croatia, and Bosnia-Herzegovina. The goal was to quantify the effect of fermentation and ripening conditions on L. monocytogenes with the simultaneous presence or absence of bacteriocin-producing lactic acid bacteria (i.e., Lactobacillus sakei). Different models were used to fit the experimental data and to calculate the kinetic parameters. The best model was chosen based on statistical comparisons. The Baranyi model was selected because it fitted the data better in most (73%) of the cases. The results from the challenge experiments and the subsequent statistical analysis indicated that relative to the control condition the addition of L. sakei strains reduced the time required for a 4-log reduction of L. monocytogenes (t4D). In contrast, the addition of the bacteriocins mesenterocin Y and sakacin P decreased the t4D values for only the Serbian product. A case study for risk assessment also was conducted. The data of initial population and t4D collected from all countries were described by a single distribution function. Storage temperature, packaging method, pH, and water activity of the final products were used to calculate the inactivation of L. monocytogenes that might occur during storage of the final product (U.S. Department of Agriculture Pathogen Modeling Program version 7.0). Simulation results indicated that the addition of L. sakei strains significantly decreased the simulated L. monocytogenes concentration of ready-to-eat fermented sausages at the time of consumption.

Metabiotic Effects of Fusarium spp. on Escherichia coli O157:H7 and Listeria monocytogenes on Raw Portioned Tomatoes

2008 ◽  
Vol 71 (7) ◽  
pp. 1366-1371 ◽  
Author(s):  
ANTONIO BEVILACQUA ◽  
FRANCESCA CIBELLI ◽  
DANIELA CARDILLO ◽  
CLELIA ALTIERI ◽  
MILENA SINIGAGLIA
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Fruits And Vegetables ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Log Reduction ◽  
Death Time ◽  
Storage Temperatures

The metabiotic effects of Fusarium proliferatum, F. avenaceum, and F. oxysporum on Escherichia coli O157:H7 and Listeria monocytogenes in fresh tomatoes were investigated. Tomatoes were preinoculated with the molds and incubated at 15°C for 7 days; then they were inoculated separately with the pathogens, packaged in air and modified atmosphere (5% O2, 30% CO2, and 65% N2), and stored at 4, 8, and 12°C for 9 days. The cell loads of pathogens and lactic acid bacteria and the pH were evaluated periodically. The data were modeled through some different mathematical models to assess the shoulder length, i.e., the time before the beginning of the exponential death phase, the 1-log reduction time (δ), and the pathogen death time (δstand). The preinoculation of tomatoes with the molds enhanced the survival of E. coli O157:H7 by prolonging shoulder length and δ parameters; this effect, however, was not observed for L. monocytogenes. pH values did not undergo significant changes within the storage time, and the lactic acid bacteria increased from 5 to 7 log CFU/g, without significant differences among the storage temperatures or the packaging atmospheres. The results of this research showed that the use of fresh tomatoes colonized by fusaria (even if the contamination is not visible) could increase significantly the risk of outbreaks due to some pathogens that could be on the surface of fruits and vegetables as a result of cross-contamination at home or incorrect postharvest operations.

scholarly journals Effect of lactic acid bacteria on Listeria monocytogenes infection and innate immunity in rabbits

2020 ◽  
Vol 65 (No. 1) ◽  
pp. 23-30 ◽  
Author(s):  
Heping Zhao ◽  
Feike Zhang ◽  
Jun Chai ◽  
Jianping Wang
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Positive Control ◽  
Negative Control ◽  
Listeriolysin O ◽  
Serum Iga ◽  
Probiotic Lactic Acid Bacteria ◽  
Spleen And Lymph Nodes ◽  
Proinflammatory Factors

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.

Inactivation of Escherichia coli O157:H7, Salmonella enterica Serotype Enteritidis, and Listeria monocytogenes on Lettuce by Hydrogen Peroxide and Lactic Acid and by Hydrogen Peroxide with Mild Heat

2002 ◽  
Vol 65 (8) ◽  
pp. 1215-1220 ◽  
Author(s):  
CHIA-MIN LIN ◽  
SARAH S. MOON ◽  
MICHAEL P. DOYLE ◽  
KAY H. McWATTERS
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Sensory Characteristics ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Log Reduction

Iceberg lettuce is a major component in vegetable salad and has been associated with many outbreaks of foodborne illnesses. In this study, several combinations of lactic acid and hydrogen peroxide were tested to obtain effective antibacterial activity without adverse effects on sensory characteristics. A five-strain mixture of Escherichia coli O157:H7, Salmonella enterica serotype Enteritidis, and Listeria monocytogenes was inoculated separately onto fresh-cut lettuce leaves, which were later treated with 1.5% lactic acid plus 1.5% hydrogen peroxide (H2O2) at 40°C for 15 min, 1.5% lactic acid plus 2% H2O2 at 22°C for 5 min, and 2% H2O2 at 50°C for 60 or 90 s. Control lettuce leaves were treated with deionized water under the same conditions. A 4-log reduction was obtained for lettuce treated with the combinations of lactic acid and H2O2 for E. coli O157:H7 and Salmonella Enteritidis, and a 3-log reduction was obtained for L. monocytogenes. However, the sensory characteristics of lettuce were compromised by these treatments. The treatment of lettuce leaves with 2% H2O2 at 50°C was effective not only in reducing pathogenic bacteria but also in maintaining good sensory quality for up to 15 days. A ≤4-log reduction of E. coli O157:H7 and Salmonella Enteritidis was achieved with the 2% H2O2 treatment, whereas a 3-log reduction of L. monocytogenes was obtained. There was no significant difference (P &gt; 0.05) between pathogen population reductions obtained with 2% H2O2 with 60- and 90-s exposure times. Hydrogen peroxide residue was undetectable (the minimum level of sensitivity was 2 ppm) on lettuce surfaces after the treated lettuce was rinsed with cold water and centrifuged with a salad spinner. Hence, the treatment of lettuce with 2% H2O2 at 50°C for 60 s is effective in initially reducing substantial populations of foodborne pathogens and maintaining high product quality.

scholarly journals Viability of lactic acid bacteria in different components of Ogi with anti diarrhoeagenic E. coli activities

2019 ◽  
Vol 3 (6) ◽  
pp. 206-213
Author(s):  
Roseline Eleojo Kwasi ◽  
Iyanuoluwa Gladys Aremu ◽  
Qudus Olamide Dosunmu ◽  
Funmilola A. Ayeni
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Antimicrobial Properties ◽  
Culture Method ◽  
Antimicrobial Activities ◽  
Drying Methods ◽  
Bacterial Strains ◽  
E Coli ◽  
Log Reduction ◽  
Freeze Dried

Background: Ogi constitutes a rich source of lactic acid bacteria (LAB) with associated health benefits to humans through antimicrobial activities. However, the high viability of LAB in Ogi and its supernatant (Omidun) is essential. Aims: This study was carried out to assess the viability of LAB in various forms of modified and natural Ogi and the antimicrobial properties of Omidun against diarrhoeagenic E coli. Methods and Material: The viability of LAB was assessed in fermented Ogi slurry and Omidun for one month and also freeze-dried Ogi with and without added bacterial strains for two months. A further 10 days viability study of modified Omidun, refrigerated Omidun, and normal Ogi was performed. The antimicrobial effects of modified Omidun against five selected strains of diarrhoeagenic E. coli (DEC) were evaluated by the co-culture method. Results: Both drying methods significantly affected carotenoids and phenolic compounds. The Ogi slurry had viable LAB only for 10 days after which, there was a succession of fungi and yeast. Omidun showed 2 log10cfu/ml reduction of LAB count each week and the freeze-dried Ogi showed progressive reduction in viability. Refrigerated Omidun has little viable LAB, while higher viability was seen in modified Omidun (≥2 log cfu/ml) than normal Omidun. Modified Omidun intervention led to 2-4 log reduction in diarrhoeagenic E. coli strains and total inactivation of shigella-toxin producing E. coli H66D strain in co-culture. Conclusions: The consumption of Ogi should be within 10 days of milling using modified Omidun. There are practical potentials of consumption of Omidun in destroying E. coli strains implicated in diarrhea. Keywords: Ogi, Omidun, lactic acid bacteria, diarrhoeagenic Escherichia coli strains, Viability.

Behavior of Listeria monocytogenes in Skim Milk during Fermentation with Mesophilic Lactic Starter Cultures

1988 ◽  
Vol 51 (8) ◽  
pp. 600-606 ◽  
Author(s):  
MICHELLE M. SCHAACK ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Skim Milk ◽  
Starter Cultures ◽  
Plate Count ◽  
Inoculum Level ◽  
Plate Count Agar ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris

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.

Microbial Safety and Quality Evaluation of UV-Treated, Cold-Pressed Colored and Turbid Juices and Beverages

2018 ◽  
Vol 81 (9) ◽  
pp. 1549-1556 ◽  
Author(s):  
JESSIE USAGA ◽  
RANDY W. WOROBO
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Uv Light ◽  
Processing Unit ◽  
Fruit And Vegetable ◽  
Processing Technologies ◽  
Constant Flow Rate ◽  
Log Reduction ◽  
Nonthermal Processing ◽  
Cold Pressed

ABSTRACT The growing demand for fruit and vegetable juice blends, with improved nutritional and sensory attributes, has prompted the industrial adoption of nonthermal processing technologies, including UV light. Limited studies have explored conditions to overcome the well-known limitations of UV when treating liquid foods with a high content of particles that absorb or scatter UV light. This study addressed the effectiveness of the application of UV light, using a commercial processing unit, to inactivate pathogenic Escherichia coli O157:H7, Salmonella enterica (hereafter Salmonella), and Listeria monocytogenes, as well as spoilage microorganisms, in colored and turbid juices and beverages. The inactivation of cocktails of five strains (or serotypes) of E. coli O157:H7, Salmonella, and L. monocytogenes isolated from fruit- and vegetable-derived products linked to outbreaks was determined in seven colored and turbid cold-pressed juices and beverages. Juices and beverages were UV treated at a constant flow rate of 150 L/h through multiple consecutive passes. The inactivation of aerobic mesophilic bacteria, molds and yeasts, and lactic acid bacteria was also assessed at the cumulative dose that guaranteed a 5-log reduction of the most UV-tolerant pathogen for each product. A 5-log reduction of the three pathogens was achieved in all juices and beverages at a maximum cumulative UV dose of 12.0 ± 0.6 mJ/cm2. The dose required to ensure the targeted reduction varied depending on the tested product and the inoculated pathogen. The reduction of aerobic mesophiles, molds and yeasts, and lactic acid bacteria varied from 0.5 to 3.6, from 0.2 to 2.0, and from 0.5 to 3.6 log CFU/mL, respectively. Thus, the proposed treatment represents a suitable processing alternative to ensure the safety and extend the shelf life of colored and turbid cold-pressed juices and beverages.

Modeling and Predicting the Growth of Lactic Acid Bacteria in Lightly Preserved Seafood and Their Inhibiting Effect on Listeria monocytogenes

2007 ◽  
Vol 70 (11) ◽  
pp. 2485-2497 ◽  
Author(s):  
OLE MEJLHOLM ◽  
PAW DALGAARD
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Chemical Characterization ◽  
Effect Of Temperature ◽  
Inhibiting Effect ◽  
Smoked Salmon ◽  
Boundary Model ◽  
Parameter Values ◽  
Separate Product

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.

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