Gram-Negative Bacteria in Refrigerated Catfish Fillets Treated with Lactic Culture and Lactic Acid†

1995 ◽  
Vol 58 (6) ◽  
pp. 639-643 ◽  
Author(s):  
C. R. KIM ◽  
J. O. HEARNSBERGER ◽  
J. B. EUN
Keyword(s):  
Lactic Acid ◽  
Crystal Violet ◽  
Storage Time ◽  
Sensory Quality ◽  
Gram Negative Bacteria ◽  
Treatment Combination ◽  
Tetrazolium Chloride ◽  
Gram Negative ◽  
Catfish Fillets

Catfish fillets were treated with combinations of lactic culture (Lactococcus lactis spp. cremoris ATCC 19257) and lactic acid using a meat tumbler. Fillets were placed individually in Ziploc bags and stored at 4 or 10°C. Counts of gram-negative bacteria on crystal violet tetrazolium chloride agar (CVT), the pH, and the sensory quality of fillets were evaluated after 0, 3, 6, and 9 days of storage time. The combination of 2.5% lactic culture and either 2% lactic acid dip (5 min) or 3% lactic acid dip (1 or 5 min) effectively (P < 0.05) inhibited counts for 9 days. The most effective treatment combination was 2.5% lactic culture incubated for 48 h and 3% lactic acid dip. The pH of samples treated with lactic culture and lactic acid ranged from 5.6 to 6.1 for 9 days at 4 or 10°C Lactic culture and lactic acid combinations extended the refrigerated shelf life of catfish for an additional 3 days at 4 and 10°C and reduced CVT counts by two log cycles over untreated fish. The combination of lactic culture and lactic acid were generally preferred for flavor and odor compared to controls after 6 and 9 days of storage, respectively.

Quality Improvement of the DNA extracted by boiling method in Gram negative bacteria

2017 ◽  
Vol 6 (04) ◽  
pp. 5347 ◽  
Author(s):  
Omar B. Ahmed* ◽  
Anas S. Dablool
Keyword(s):  
Dna Extraction ◽  
Control Method ◽  
Extraction Procedure ◽  
Cost Effective ◽  
High Yield ◽  
Gram Negative Bacteria ◽  
Bacterial Dna ◽  
Gram Negative ◽  
E Coli

Several methods of Deoxyribonucleic acid (DNA) extraction have been applied to extract bacterial DNA. The amount and the quality of the DNA obtained for each one of those methods are variable. The study aimed to evaluate bacterial DNA extraction using conventional boiling method followed by alcohol precipitation. DNA extraction from Gram negative bacilli was extracted and precipitated using boiling method with further precipitation by ethanol. The extraction procedure performed using the boiling method resulted in high DNA yields for both E. coli and K. pneumoniae bacteria in (199.7 and 285.7μg/ml, respectively) which was close to control method (229.3 and 440.3μg/ml). It was concluded that after alcohol precipitation boiling procedure was easy, cost-effective, and applicable for high-yield quality of DNA in Gram-negative bacteria.

In Vitro antibacterial activity of lactic acid bacteria isolated from goat’s raw milk of Mostaganem (West Algeria) against Gram negative bacteria responsible for urinary tract infections

2016 ◽  
Vol 6 (1) ◽  
pp. 15-22
Author(s):  
Zergoug Amina ◽  
Cheriguene Abderrahim ◽  
Chougrani Fadela
Keyword(s):  
Antibacterial Activity ◽  
Lactic Acid ◽  
Urinary Tract ◽  
Lactic Acid Bacteria ◽  
Raw Milk ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Tract Infections ◽  
West Algeria

Urinary tract infections (UTI) are a serious bacterial pathological challenges all over the world, leading to respiratory infections, that’s why new strategies don’t cease to develop. Lactic acid bacteria having shown beneficial effects for years in various areas, may prove to be excellent candidates in medical field. The current research focused on the selection of lactic acid bacteria having the potential of an antibacterial activity against Gram negative bacteria responsible for UTI, for an eventual use as a therapeutic agent. A total of 40 isolates were isolated from goat’s raw milk of Mostaganem (West Algeria). In vitro tests were conducted in order to determine the efficiency of the isolates to produce antibacterial agents in interaction with uropathogens. Among 40 isolates, only 10 isolates identified as Lactobacilli and Lactococci were performant. The Screening showed that the inhibitor agent was proteinaceous substance. Therfore, it is noted that a treatment with presence of LAB is very encouraging as a result of the production of bacteriocin-like substance. On the other hand, LAB can be considered as a good alter-native to the large extent to the antibiotics in the treatment of UTI.

Evaluation of Inhibitors for Rapid Enumeration of Psychrotrophic Bacteria

1979 ◽  
Vol 42 (2) ◽  
pp. 158-160 ◽  
Author(s):  
TERRANCE L. SMITH ◽  
L. D. WITTER
Keyword(s):  
Crystal Violet ◽  
Gram Negative Bacteria ◽  
Basic Fuchsin ◽  
Gram Positive ◽  
Gram Negative ◽  
Psychrotrophic Bacteria ◽  
Gram Positive Bacteria ◽  
Rapid Enumeration

Two inhibitors of the 17 tested inhibited growth of gram positive bacteria without causing inhibition of gram negative bacteria. These were crystal violet at 2 mg/1 and neotetrazolium chloride at 2 mg/1. In addition, basic fuchsin at 6 mg/1 produced only marginal reduction in counts of gram negative bacteria. These inhibitors might find further use in developing a test for psychrotrophic bacteria in the presence of non-psychrotrophic bacteria.

Influence of Modified Atmosphere Packaging on the Microflora and Quality of Fresh Bell Peppers

1990 ◽  
Vol 53 (3) ◽  
pp. 255-257 ◽  
Author(s):  
R. E. BRACKETT
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Sensory Quality ◽  
Modified Atmosphere Packaging ◽  
Modified Atmosphere ◽  
Surface Ph ◽  
Color Changes ◽  
Bell Peppers ◽  
Yeasts And Molds

Fresh bell peppers were individually shrink-wrapped in film (SW), sealed in gas-flushed (5% O2, 10% CO2, 85% N2) film (GP) pouches, or stored unpackaged in cardboard packing crates (CN). All samples were stored at 13°C and changes in populations of total aerobic microorganisms, yeasts and molds, members of Enterobacteriaceae, and lactic acid bacteria were determined. In addition, overall sensory quality, color changes, and surface pH were monitored. SW peppers developed higher populations of total aerobic microorganisms, yeasts and molds, and Enterobacteriaceae than did CN peppers, but populations of other groups of microorganisms were similar. Color and surface pH of peppers did not differ in any of the treatments. SW and GP peppers remained unspoiled at least 6 weeks, whereas CN peppers spoiled in 3 weeks.

Method of Applying Sanitizers and Sample Preparation Affects Recovery of Native Microflora and Salmonella on Whole Cantaloupe Surfaces†

2004 ◽  
Vol 67 (5) ◽  
pp. 999-1004 ◽  
Author(s):  
DIKE O. UKUKU ◽  
WILLIAM F. FETT
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Treatment Method ◽  
Microbial Populations ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Selective Media ◽  
Selective Agar ◽  
Agar Media ◽  
Native Microflora

Standardized methods for applying sanitizer treatments to cantaloupes and for recovering surviving native microflora or Salmonella on inoculated cantaloupe after sanitizing are lacking. Accordingly, the objectives of this study were to compare four methods for applying sanitizers (dipping, dipping with rotation, dipping with agitation, and dipping with rubbing) using 200 ppm of chlorine or 5% H2O2, two recovery methods (homogenization of rind plugs in a stomacher or blender), and five selective recovery media for Salmonella. Whole cantaloupes were submerged in a cocktail of five strains of Salmonella (each at approximately 2 × 108 CFU/ml) for 10 min and allowed to dry for 1 h inside a biosafety cabinet and stored at 20° C for approximately 23 h before sanitizing. The recovery of Salmonella from whole cantaloupe without sanitizing averaged 5.09 log CFU/cm2 by blending and 4.30 log CFU/cm2 by homogenization in a stomacher for the five selective agar media. Microbial populations ( Salmonella or the indigenous aerobic mesophilic bacteria, gram-negative bacteria, lactic acid bacteria, Pseudomonas spp., and yeast and mold) were not significantly (P > 0.05) reduced by treating with water regardless of the treatment method used. Sanitizing with chlorine or H2O2 by dipping, with or without rotation for 2 min, also did not reduce microbial populations. However, populations of all classes of native microflora and Salmonella were significantly (P < 0.05) reduced by sanitizer treatments (2 min) applied with agitation or by rubbing. In general, sanitizer treatments applied by rubbing resulted in greater log reductions (by up to 1.7 log unit) than for treatments applied with agitation. Populations of native microflora and Salmonella recovered from cantaloupe were higher (by up to 1.8 log unit) by blending compared to homogenization in a stomacher. In most instances, selective media used did not differ significantly (P > 0.05) for recovery of Salmonella after washing treatments.

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