Listeria monocytogenes Survival in Refrigerator Dill Pickles

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
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Room Temperature ◽  
Population Decline ◽  
Titratable Acidity ◽  
Growth Patterns ◽  
Refrigerated Storage ◽  
Nacl Concentration ◽  
Pickling Cucumbers

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.

scholarly journals Survival of selected lactic acid bacteria isolated from pineapple waste in refrigerated pineapple juices

2018 ◽  
Author(s):  
Jannette Wen Fang Wu ◽  
Lidieth Uribe ◽  
Rodolfo WingChing-Jones ◽  
Jessie Usaga ◽  
Natalia Barboza
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Organic Acids ◽  
Bile Salts ◽  
Titratable Acidity ◽  
Probiotic Properties ◽  
Refrigerated Storage ◽  
Pineapple Juice ◽  
Pineapple Waste ◽  
Solids Content

ABSTRACTThe aim of this research was to isolate and identify lactic acid bacteria (LAB) from pineapple waste. The survival in refrigerated pineapple juices, of a selected isolate with potential probiotic properties, was also studied. The 16S rRNA andpheSpartial genes were used to identify LAB, multilocus sequence typing (MLST) genes were used in order to separate strains grouping withLactobacillus caseiandL. paracaseiphylogenetically. Tests for survival at pH 2.0, resistance to lysozyme and tolerance to bile salts were used to screen the strains for potential probiotic properties. AL. fermentumisolate was used for the survival study. Three types of pineapple juice made from pulp, a blend of pulp and peel (80:20), and peel extract were inoculated to approximately 106CFU/mL withL. fermentumand stored at 4 °C for up to six weeks. The physicochemical composition of juices, including concentration of fermentable sugars and organic acids, total solids content, soluble solids content, titratable acidity and pH, was determined during the survival study. Two genera and five species were identified. Pineapple juices supported the survival ofL. fermentumduring refrigerated storage but the population of the bacteria decreased over time regardless of the juice type. Juice made from pulp was a more suitable vehicle for the survival of the selected LAB. Some of the juice physicochemical properties, including sugars and organic acids content, pH and titratable acidity, varied significantly (P<0.05) during storage. Further sensory studies are necessary to evaluate consumer acceptance of juices containing the selected isolate.IMPORTANCELactic acid bacteria (LAB), isolated from pineapple waste, were phylogenetically analyzed and characterized in regards to their tolerance to pH 2.0, lysozyme and bile salts; showing their potential as probiotic strains, if health benefits associated to their ingestion are eventually confirmed. Moreover, pineapple juice supported the survival ofLactobacillus fermentum, isolated from the same food matrix, during refrigerated storage at 4 °C. Among the three pineapple juices tested (pulp, pulp + peel and peel),L. fermentumsurvived better in juice made from pulp. However, significant variations were observed overtime in some of the physicochemical properties of the juices including sugars and organic acids content, pH and total titratable acidity.

Effect of Pullulan on Physicochemical, Microbiological, and Sensory Quality of Yogurts

2019 ◽  
Vol 20 (6) ◽  
pp. 489-496 ◽  
Author(s):  
Anna Chlebowska-Śmigiel ◽  
Katarzyna Kycia ◽  
Katarzyna Neffe-Skocińska ◽  
Marek Kieliszek ◽  
Małgorzata Gniewosz ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Sensory Quality ◽  
Culture Medium ◽  
Titratable Acidity ◽  
Refrigerated Storage ◽  
Ph Change ◽  
Fermentation Capacity ◽  
Dietetic Food

Background: Pullulan can partially or completely replace starch or fat, thanks to which it can be used for the production of dietetic food. It allows you to maintain the desired consistency, and increases the viscosity of the product. Objective: Therefore, an attempt was made to produce yogurts with pullulan addition and determine the effect of its presence on the number of LAB, pH change, titratable acidity, and sensory quality of yogurts during storage at 4°C for 28 days. Method: The effect of addition of 0; 1.0 and 2.0 % w/v pullulan as a yogurt ingredient on the changes in pH, acidity, LAB number, and sensory quality of yogurt during storage at 4°C for 28 days was examined. Results: Pullulan did not affect yogurt pH, but the addition of 2.0 % w/v pullulan increased the acidity of yogurt as compared to that of the control yogurt. A statistically significantly higher total number of Lactobacillus, by approximately 1 logarithmic cycle, was found in yogurts with pullulan than in the control yogurt on the 28th day of storage. The yogurt with 1.0% w/v pullulan addition showed better sensory characteristics than that with 2.0% pullulan w/v addition. Conclusion: The conducted research proved that the presence of pullulan in the culture medium stimulates the growth of selected lactic acid bacteria and influences their fermentation capacity. The use of 1.0 % w/v pullulan during the production of yogurts allowed to obtain a sensorically acceptable product, it had a protective effect on the number of lactic acid bacteria during 28 days of refrigerated storage of yogurt.

scholarly journals Microbiological dynamics involved in cereal-porridge production using maize and sorghum

2022 ◽  
Vol 18 (1) ◽  
pp. 014-026
Author(s):  
Mercy M Umokaso ◽  
Bernard JO Efiuvwevwere ◽  
Francis S Ire
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Ph Value ◽  
Titratable Acidity ◽  
Bacterial Count ◽  
Growth Patterns ◽  
Lactobacillus Fermentum ◽  
Coliform Bacteria ◽  
Spontaneous Fermentation ◽  
Candida Sp

Cereal-porridge(‘ogi’) was produced by spontaneous fermentation using maize and sorghum substrates. The microbiological dynamics involved were monitored over a period of 48h fermentation. Bacteria, yeasts and moulds were isolated. Based on the morphological, cultural and biochemical test results, the aerobic bacterial isolates were identified as Proteus vulgaris, Proteus mirabilis, Klebsiella sp, Staphylococcus aureus, Lactobacillus sp, Pseudomonas sp, Citrobacter sp, Bacillus sp, Proteus sp, Shigella sp, and Escherichia coli. The Lactic acid bacteria were Lactococcus sp, Enterococcus sp, Lactobacillus fermentum, Lactobacillus sp. The yeast isolates were 2 strains of Saccharomyces cerevisiae, one other Saccharomyces sp and a Candida sp. The moulds were Aspergillus niger, Aspergillus flavus, Rhizopus sp and Penicillium sp. The lactic acid bacteria (LAB) isolated were 2 strains of Lactococcus lactis, 2 Enterobacter spp, 5 strains of Lactobacillus fermentum and 1 other Lactobacillus sp. The initial total viable aerobic bacterial count at 0h in maize, sorghum and maize-sorghum blend were 4.6 × 104, 7.3 × 104 and 2.4 × 105cfu/ml respectively. The growths rose to peaks of 6.5 × 107 and 3.9 × 107cfu/ml at 24h in maize and maize-sorghum blend, respectively. A Peak of 4.7 x 107cfu/ml was attained at 36h in sorghum. Coliform bacteria and moulds growths in the three samples attained peaks of growth at 12h and reduced till there was no growth by 48h. Lactic acid bacteria and yeasts increased in numbers till the end of fermentation. The initial pH value at 0h was lowest in maize-sorghum blend sample (5.43) and highest in maize (5.75). Final values at 48h were 3.76, 3.78 and 3.75 in maize, sorghum and maize-sorghum blend samples respectively. There were no significant differences between the microbial growth patterns, changes in pH, total titratable acidity (TTA) and amylase enzymatic activities in maize, sorghum and maize-sorghum blend samples during fermentation.

Occurrence of Listeria monocytogenes in Green Table Olives

2004 ◽  
Vol 67 (10) ◽  
pp. 2189-2194 ◽  
Author(s):  
CINZIA CAGGIA ◽  
CINZIA L. RANDAZZO ◽  
MONIA DI SALVO ◽  
FLORA ROMEO ◽  
PAOLO GIUDICI
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Titratable Acidity ◽  
Starter Cultures ◽  
Table Olives ◽  
Olive Cultivar ◽  
Lactobacillus Pentosus ◽  
Microbiological Safety ◽  
Biological Methods

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.

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.

Physicochemical, microbiological, and sensory characteristics of probiotic Bulgarian yoghurts obtained by ultrafiltration of goat’s milk

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mariya Dushkova ◽  
Siyka Kodinova ◽  
Zapryana Denkova ◽  
Velichka Yanakieva ◽  
Nikolay Dimitrov Menkov
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Acidophilus ◽  
Dry Matter ◽  
Titratable Acidity ◽  
Bifidobacterium Bifidum ◽  
Sensory Characteristics ◽  
Viable Cells ◽  
Goat’S Milk ◽  
Goat's Milk

Abstract The purpose of this study was to investigate the microbiological (number of viable lactic acid bacteria and bifidobacteria), physicochemical (dry matter, protein and fat contents, titratable acidity, and pH), and sensory characteristics (appearance of coagulum, taste and aroma, structure at cutting, color, and consistency at shattering) of probiotic Bulgarian yoghurts obtained by ultrafiltration of goat’s milk. These yoghurts were obtained using volume reduction ratios of 2 and 3 with the probiotic starters MZ2f, MZ2f + Bifidobacterium bifidum BB – 87, and MZ2f + Lactobacillus acidophilus LAB – 8. The increase in the level of the concentration by ultrafiltration led to an increase in the dry matter, protein and fat contents of the yoghurts, in the number of lactic acid bacteria and titratable acidity, and to a decrease in the pH. The twofold concentration by ultrafiltration resulted in a higher number of lactic acid bacteria in comparison with yoghurts made without ultrafiltration, and with better sensory characteristics compared to yoghurts without and with threefold ultrafiltration. The higher number of viable cells and better sensory characteristics were obtained for yoghurts with MZ2f + Bifidobacterium bifidum BB – 87 and MZ2f + Lactobacillus acidophilus LAB – 8 in comparison with MZ2f alone.

scholarly journals Production of Nigerian Yoghurt Using Lactic Acid Bacteria as Starter Cultures

2020 ◽  
pp. 32-42
Author(s):  
S. Aforijiku ◽  
S. M. Wakil ◽  
A. A. Onilude
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Proximate Composition ◽  
Room Temperature ◽  
Starter Cultures ◽  
Cow Milk ◽  
Spontaneous Fermentation ◽  
Overall Acceptability ◽  
Fermentation Control ◽  
Better Than

Aim: This work was carried out to investigate the influence of Lactic Acid Bacteria (LAB) on organoleptic quality and proximate composition of yoghurt, and viability of starter cultures in yoghurt. Methods: The LAB starter cultures were selected based on their ability to produce diacetyl and lactic acid. Results: Lactobacillus caseiN1 produced the highest quantity (2.72 g/L) of diacetyl at 48 hrs of incubation while Pediococcus acidilacticiG1 had the lowest amount (0.50 g/L). The pH of produced yoghurt ranged between 4.40 and 5.58 while the corresponding lactic acid contents ranged between 0.70 and 0.96 g/L. Yoghurt produced with cow milk inoculated with L. PlantarumN24 and L. BrevisN10 had the lowest pH (4.40) at significant level of P≤0.05. Yoghurt with mixed culture of L. PlantarumN24 and L. PlantarumN17 had the highest protein content (5.13%) while spontaneous fermentation (control) produced the least (0.48%). Yoghurt produced from cow milk inoculated with L. PlantarumN24 and L. PlantarumN17 was rated best with overall acceptability (9.0) during first day of storage while the commercial yoghurt (5.8) and spontaneous fermentation (6.8) had least overall acceptability at P≤0.05. Conclusion: Yoghurt samples stored in refrigerator had more viable LAB counts for a period of 21 days while the samples stored at room temperature had a day count except for yoghurt produced with cow milk inoculated with L. plantarumN24 which retained its viability at the second day. The yoghurt produced with selected LAB starters are better than commercial yoghurt in terms of sensory properties, proximate composition, pH and 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.

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