scholarly journals Antimicrobial activity of the Nisin Z producer Lactococcus lactis subsp. lactis Lc08 against Listeria monocytogenes in skim milk

2013 ◽  
Vol 65 (5) ◽  
pp. 1554-1560 ◽  
Author(s):  
L.M. Perin ◽  
R.O. Miranda ◽  
A.C. Camargo ◽  
M. Colombo ◽  
A.F. Carvalho ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Listeria Monocytogenes ◽  
Lactococcus Lactis ◽  
Food Systems ◽  
Skim Milk ◽  
In Vitro Tests ◽  
Lactococcus Lactis Subsp ◽  
Ph Values ◽  
Nisin Z

The presented study aimed to verify the effect of different pH values, enzyme solutions and heat treatments on the antimicrobial activity of the bacteriocinogenic strain Lactococcus lactis subsp. lactis Lc08 and to test their antimicrobial activity against Listeria monocytogenes in reconstituted skim milk at refrigeration temperatures. This strain was previously described as a nisin Z producer and capable of inhibiting L. monocytogenes growth in in vitro tests. The antimicrobial activity of the bacteriocin cell-free supernatant of Lc08 was sensitive to enzyme treatments (except papain). The pH values and heating (65ºC for 30min, 75ºC for 15s) had no apparent effect on the antimicrobial activity of the bacteriocin produced by Lc08. Only treatment at autoclave conditions result in loss of their antimicrobial activity. Lc08 presented antimicrobial activity against L. monocytogenes in the milk system after 12h at 25ºC. No effect was found at 7ºC. The results show the application viability of the Lc08 in food systems as a biopreservative against L. monocytogenes.

A Foodgrade Preparation of Nisin from Diluted Milk Fermented with Lactococcus lactis W8

2009 ◽  
Vol 72 (12) ◽  
pp. 2615-2617 ◽  
Author(s):  
SURANJITA MITRA ◽  
BIDHAN CHANDRA MUKHOPADHYAY ◽  
SWADESH RANJAN BISWAS
Keyword(s):  
Antimicrobial Activity ◽  
Lactococcus Lactis ◽  
Food Industry ◽  
Skim Milk ◽  
Cost Effective ◽  
Fermented Milk ◽  
Maximum Production ◽  
Nisin Z ◽  
Liquid Part ◽  
Lactis Strain

Lactococcus lactis strain W8, which contains the nisin Z gene in its genome, grew well and produced nisin in cow's milk at temperatures of 30 to 37°C. Maximum production of nisin was achieved at 6 h and was 4,000 activity units (AU) per ml in skim milk and 2,400 AU/ml in 3% fat milk. The organism produced nisin even in 20 times diluted skim milk and 3% fat milk at 1,000 and 600 AU/ml, respectively. Boiling of the fermented milk (pH 4.2) made with this culture allowed the separation of the liquid part (whey) from the curd. When 20 times diluted skim milk was fermented and the whey derived from it was lyophilized, the yield of nisin was 60,000 AU/g. The antimicrobial activity of the nisin preparation was stable for at least 1 year at refrigeration temperature. L. lactis W8 may have significant applications in the food industry for a cost-effective natural nisin preparation.

Effect of pH, Acidulant, Time, and Temperature on the Growth and Survival of Listeria monocytogenes

1989 ◽  
Vol 52 (8) ◽  
pp. 571-573 ◽  
Author(s):  
KENT M. SORRELLS ◽  
DAVIN C. ENIGL ◽  
JOHN R. HATFIELD
Keyword(s):  
Antimicrobial Activity ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Citric Acid ◽  
Hydrochloric Acid ◽  
Malic Acid ◽  
Incubation Temperature ◽  
Growth And Survival ◽  
Ph Values

The effect of different acids, pH, incubation time, and incubation temperature on the growth and survival of four strains of Listeria monocytogenes in tryptic soy broth was compared. Hydrochloric acid (HCl), acetic acid (AA), lactic acid (LA), malic acid (MA), and citric acid (CA) were used to acidify tryptic soy broth to pH values 4.4, 4.6, 4.8, 5.0, and 5.2 pH. Incubation times were 1, 3, 7, 14, and 28 d at 10, 25, and 35°C. The inhibition of L. monocytogenes in the presence of high acidity appears to be a function of acid and incubation temperature. Based on equal pH values, the antimicrobial activity is AA > LA > CA ≥ MA > HCl at all incubation times and temperatures. When based on equal molar concentration, the activity appeared to be CA ≥ MA > LA ≥ AA > HCl at 35 and 25°C, and MA > CA > AA ≥ LA > HCl at 10°C. Greatest antimicrobial activity occurred at 35°C. Greatest survival occurred at 10°C and greatest growth occurred at 25°C. Final pH of the medium was as low as 3.8 in HCl at 28 d. All strains grew well at pH values lower than the minimum previously reported (5.5–5.6).

Identification and Characteristics of Nisin Z-Producing Lactococcus lactis subsp. lactis Isolated from Kimchi

2003 ◽  
Vol 46 (5) ◽  
pp. 385-388 ◽  
Author(s):  
Sang-Hee Park ◽  
Kikuji Itoh ◽  
Eisaku Kikuchi ◽  
Hidekazu Niwa ◽  
Tomohiko Fujisawa
Keyword(s):  
Lactococcus Lactis ◽  
Lactococcus Lactis Subsp ◽  
Nisin Z

Inhibition of a Methicillin-Resistant Staphylococcus aureus Strain in Afuega'l Pitu Cheese by the Nisin Z–Producing Strain Lactococcus lactis subsp. lactis IPLA 729

2004 ◽  
Vol 67 (5) ◽  
pp. 928-933 ◽  
Author(s):  
NATALIA RILLA ◽  
BEATRIZ MARTÍNEZ ◽  
ANA RODRÍGUEZ
Keyword(s):  
Staphylococcus Aureus ◽  
Lactococcus Lactis ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Aureus Strain ◽  
Northern Spain ◽  
Potential Threat ◽  
Methicillin Resistant ◽  
Initial Inoculum ◽  
Lactococcus Lactis Subsp ◽  
Nisin Z

Methicillin-resistant Staphylococcus aureus strains are a potential threat for food safety because foodborne illness caused by methicillin-resistant Staphylococcus aureus has been reported even though these strains were only associated with nosocomial infections until recently. This article focuses on the inhibitory effect of the nisin Z–producing strain Lactococcus lactis subsp. lactis IPLA 729 on the growth of Staphylococcus aureus CECT 4013, a methicillin-resistant strain. S. aureus was inhibited by the presence of the nisin producer IPLA 729 in buffered Trypticase soy broth, milk, and Afuega'l Pitu cheese, an acid-coagulated cheese manufactured in Asturias, Northern Spain. A reduction of 3.66 log units was observed in Trypticase soy broth at the end of the incubation period. In milk, viable counts of S. aureus were undetectable or were reduced by 2.16 log units in 24 h depending on the initial inoculum (1.8 × 104 and 7.2 × 106 CFU/ml). The staphylococcal strain was also undetected in test cheeses in which the nisin Z producer was present whereas 2 log units were detected in control cheeses at the end of ripening.

scholarly journals Complete Genome Sequence of Lactococcus lactis subsp. lactis Strain 14B4, Which Inhibits the Growth of Salmonella enterica Serotype Poona In Vitro

2018 ◽  
Vol 7 (19) ◽  
Author(s):  
Thao D. Tran ◽  
Steven Huynh ◽  
Craig T. Parker ◽  
Ruyang Han ◽  
Robert Hnasko ◽  
...  
Keyword(s):  
Lactococcus Lactis ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Salmonella Enterica ◽  
Complete Genome ◽  
Northern California ◽  
Content Type ◽  
Lactococcus Lactis Subsp ◽  
Lactis Strain

We present here the complete genome sequence of Lactococcus lactis strain 14B4, isolated from almond drupes in northern California. This strain was observed to inhibit the growth of Salmonella enterica serotype Poona strain RM3363 in vitro.

The antibacterial activity expressed in vitro and in vivo by Lactococcus lactis subsp. lactis CNRZ 1427 against Salmonella sp.

2015 ◽  
Vol 4 (5) ◽  
pp. 240-246
Author(s):  
Menad Najett ◽  
Chougrani Fadelaa ◽  
Moghtet Snoussi ◽  
Cheriguene Abderrahim
Keyword(s):  
Antibacterial Activity ◽  
Lactococcus Lactis ◽  
Bile Salts ◽  
Therapeutic Agent ◽  
Lactococcus Lactis Subsp ◽  
Beneficial Effects ◽  
Gastrointestinal Conditions ◽  
Therapeutic Possibilities

  The present study focused on the beneficial effects of Lactococcus lactis subsp lactis CNRZ 1427 with possible use as a therapeutic agent against Sal-monella sp.; also we have proposed different therapeutic possibilities of our situation against a pathogen Salmonella sp. We have conducted two tests In Vitro and In Vivo; where it is noted that treatment in the presence of this lac-tic strain is effective since it causes a remarkable decrease of the pathogen agent. At the end, the effectiveness of this lactic strain was confirmed by testing for resistance to gastrointestinal conditions (pH, bile salts and diges-tive enzymes).

Behavior of Listeria monocytogenes at 4 and 22°C in Whey and Skim Milk Containing 6 or 12% Sodium Chloride

1989 ◽  
Vol 52 (9) ◽  
pp. 625-630 ◽  
Author(s):  
DEMETRIOS K. PAPAGEORGIOU ◽  
ELMER H. MARTH
Keyword(s):  
Listeria Monocytogenes ◽  
Sodium Chloride ◽  
Skim Milk ◽  
Salt Tolerant ◽  
Ph Values ◽  
Generation Times ◽  
Order Of Magnitude ◽  
Entire Experiment

Autoclaved samples of skim milk and deproteinated whey were fortified with 6 or 12% NaCl, inoculated with Listeria monocytogenes strains Scott A or California (CA), to contain ca. 1.0 × 103 cfu/ml (in the products with 6% salt) or ca. 5.0 × 103 cfu/ml (in the products with 12% salt) and incubated at 4 and 22°C. The pH values of the 6% salted whey, 6% salted skim milk, 12% salted whey, and 12% salted skim milk were 5.65, 6.20, 5.50, and 6.00 respectively. These values remained relatively constant during the entire experiment. Listeria counts were obtained by surface-plating appropriate dilutions and/or undiluted samples on Trypticase Agar (TA). Samples in which L. monocytogenes was not detected, were re-examined after 2, 4, 6 and 8 weeks of cold-enrichment. Generation times of L. monocytogenes in 6% salted whey at 22°C (3.67 h and 3.56 h for strains Scott A and CA, respectively) were significantly shorter than those in 6% salted skim milk at 22°C (4.31 and 4.42 h for the two strains, respectively). Generation times in 6% salted products at 4°C ranged between 37.49 h and 49.43 h. Maximum populations reached at 22 and 4°C ranged from 7.58 to 8.10 Log10 cfu/ml, and were significantly higher in 6% salted whey than in 6% salted skim milk. In 12% salted whey and skim milk incubated at 22°C, L. monocytogenes gradually decreased in numbers. Strain CA was inactivated within 85 d in 12% salted skim milk or within 110 d in 12% salted whey, and was significantly less salt tolerant than strain Scott A which survived for more than 130 d under the same conditions. Loss of viability by both strains was similar in 12% salted whey and skim milk after 130 d of storage at 4°C, and the decreases in population were less than 0.7 order of magnitude.

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