scholarly journals Effect of an Italian propolis on the growth of Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus in milk and whey cheese

2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Francesca Pedonese ◽  
Giada Verani ◽  
Beatrice Torracca ◽  
Barbara Turchi ◽  
Antonio Felicioli ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Listeria Monocytogenes ◽  
Bacillus Cereus ◽  
Dairy Products ◽  
Skim Milk ◽  
Cow’S Milk ◽  
Alcoholic Extract ◽  
Cow's Milk

Propolis antimicrobial activity has been limitedly studied in food, particularly in dairy products. We studied the antimicrobial activity of an alcoholic extract of an Italian propolis in sterile skim milk, pasteurized cow’s milk, and cow’s and goat’s whey cheese (ricotta). Following the determination of the minimal inhibitory concentration on Gram+ and Gram- bacteria, the extract was employed at 2 and 5% (P2, P5), using controls with the same ethanol concentrations (E2, E5) and without any addition. In milk trials, Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, and Pseudomonas fluorescens were tested. P2 and P5 samples registered significant decreases of Gram+ bacteria in skim milk. The same was true for P5 in cows’ milk, but only with S. aureus for P2. Ricotta was inoculated with L. monocytogenes, S. aureus and B. cereus and stored at 8.5°C. In cow’s milk ricotta, L. monocytogenes counts in P5 were always lower than control during the storage time, significantly so from the 14th day. In goat’s ricotta, L. monocytogenes counts in P5 were at least one logarithm lower than E5, whereas the extract didn’t show a significant effect on S. aureus and B. cereus. The antimicrobial activity of propolis, particularly on L. monocytogenes, could be employed in ready-to-eat refrigerated dairy products.

The Antimicrobial Activity of Extracts of the Lichen Cetraria aculeata and Its Protolichesterinic Acid Constituent

2003 ◽  
Vol 58 (11-12) ◽  
pp. 850-854 ◽  
Author(s):  
Ayşen Özdemir Türk ◽  
Meral Yılmaz ◽  
Merih Kıvanç ◽  
Hayrettin Türk
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Bacillus Subtilis ◽  
Listeria Monocytogenes ◽  
Bacillus Cereus ◽  
Aeromonas Hydrophila ◽  
Proteus Vulgaris ◽  
Ethanol Extracts

Abstract In this study, the antimicrobial activity of the acetone, diethyl ether and ethanol extracts of the lichen Cetraria aculeata has been investigated. The extracts were tested against twelve bacteria and eight fungi and found active against Escherichia coli, Staphylococcus aureus, Aeromonas hydrophila, Proteus vulgaris, Streptococcus faecalis, Bacillus cereus, Bacillus subtilis, Pseudomonas aeruginosa, Listeria monocytogenes. No antimicrobial activity against the fungi was detected. It was determined that only one substance in the extracts has antimicrobial activity and it was characterized as protolichesterinic acid. The MICs of the extracts and protolichesterinic acid were also determined.

scholarly journals Staphylococcus aureus of raw cow's milk

2021 ◽  
Vol 23 (102) ◽  
pp. 53-59
Author(s):  
M. D. Kukhtyn ◽  
Y. V. Horiuk ◽  
V. Z. Salata ◽  
V. T. Klymyk ◽  
N. M. Vorozhbit ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Raw Milk ◽  
Cow’S Milk ◽  
Cow's Milk ◽  
Milk Samples ◽  
Before And After ◽  
Pure Cultures ◽  
Almost All

The presence of Staphylococcus aureus in raw milk is considered a direct danger to consumers. Almost all types of dairy products normalize the amount of Staphylococcus aureus in 1 g (cm3) of product, due to their ability to produce thermostable enterotoxins. The aim of the study was to investigate the role of incision of teats of healthy and sick mastitis cows and milking equipment for irradiation of cow's milk with Staphylococcus aureus. Sanitation of milking equipment in farms was carried out with alkaline detergents based on sodium hypochlorite and acid based on phosphoric acid. Blood agar with 5 % sodium chloride was used to isolate staphylococci from washes and milk. Species identification of pure cultures of staphylococci was performed using RapID Staph Plus kits. At the same time before and after milking the skin of teats with Udder Wash and Udder Forte reduces the incidence of Staphylococcus aureus to 4.1 ± 0.3 % of cases. Quantitative determination of staphylococci, including golden on the skin of the teats revealed a decrease in the latter from 283.5 ± 21.2 to 27.6 ± 2.1 CFU/cm3 flush after milking. It has been established that the number of staphylococci, including golden, on the skin of teats increases sharply under subclinical or clinical ointment. Thus, it was found that in the subclinical form of staphylococcal mastitis from the skin of teats isolated S. aureus in the amount of 790.6 ± 65.4 CFU/cm3 of wash. At the same time, in the clinical form of mastitis, the amount of S. aureus increased, on average to 8 thousand CFU/cm3 of flush. It was found that under the condition of sanitary treatment of milking equipment with alternate use of alkaline and acid detergents and disinfectants, only 25 % of washes were staphylococci, and gold – up to 5 % of samples. It was found that in 43.7 ± 3.9 % of raw milk samples Staphylococcus aureus was not detected in 1 cm3. The number of milk samples containing Staphylococcus aureus up to 100 CFU/cm3 was 39.1 ± 3.3 %, and 17.2 ± 1.4 % of milk samples were contaminated with Staphylococcus aureus in the amount of 101 to 200 CFU/cm3. Therefore, the presence of more than 200 CFU/cm3 in freshly milked Staphylococcus aureus in milk indicates the ineffectiveness of antimastitis measures, skin remediation of teats and sanitation of milking equipment.

scholarly journals Antimicrobial Activity of Six International Artisanal Kefirs against Bacillus cereus, Listeria monocytogenes, Salmonella enterica Serovar Enteritidis, and Staphylococcus aureus

2020 ◽  
Vol 8 (6) ◽  
pp. 849 ◽  
Author(s):  
Abrar Sindi ◽  
Md. Bahadur Badsha ◽  
Barbara Nielsen ◽  
Gülhan Ünlü
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Listeria Monocytogenes ◽  
Bacillus Cereus ◽  
Foodborne Pathogens ◽  
Salmonella Enterica ◽  
Antimicrobial Activities ◽  
Negative Control ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Bacterial Indicator

Kefir, a fermented dairy beverage, exhibits antimicrobial activity due to many metabolic products, including bacteriocins, generated by lactic acid bacteria. In this study, the antimicrobial activities of artisanal kefir products from Fusion Tea (A), Britain (B), Ireland (I), Lithuania (L), the Caucuses region (C), and South Korea (K) were investigated against select foodborne pathogens. Listeria monocytogenes CWD 1198, Salmonella enterica serovar Enteritidis ATCC 13076, Staphylococcus aureus ATCC 25923, and Bacillus cereus ATCC 14579 were inhibited by artisanal kefirs made with kefir grains from diverse origins. Kefirs A, B, and I inhibited all bacterial indicator strains examined at varying levels, except Escherichia coli ATCC 12435 (non-pathogenic, negative control). Kefirs K, L, and C inhibited all indicator strains, except S. aureus ATCC 25923 and E. coli ATCC 12435. Bacteriocins present in artisanal kefirs were determined to be the main antimicrobials in all kefirs examined. Kefir-based antimicrobials are being proposed as promising natural biopreservatives as per the results of the study.

scholarly journals THE DEVELOPMENT OF THE METHOD FOR THE DETERMINATION OF SULFONAMIDES AND TRIMETOPRIM RESIDUAL QUANTITIES IN MILK SAMPLES BY UPLC-MS/MS METHOD AND ITS VERIFICATION THROUGH INTERLABORATORY TESTING

2020 ◽  
Vol 21 (2) ◽  
pp. 170-182
Author(s):  
M. Rydchuk ◽  
S. Plotycya ◽  
D. Yanovych ◽  
Z. Zasadna ◽  
S. Kislova ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Dairy Products ◽  
Milk Powder ◽  
Cow’S Milk ◽  
Cow's Milk ◽  
Milk Samples ◽  
Powder Samples ◽  
Tandem Mass Spectrometric ◽  
Fast Procedure

This manuscript presents the results of development and adoption of the confirmatory UPLC- MS/MS method for determination of sulfonamides and trimethoprim residues in whole and powdered cow's milk samples. Sample preparation includes a recovery with water (in the case of milk powder), separation of milk fat by centrifugation at 4 °C, proteins precipitation with acetonitrile using ultrasonic intensification, extraction of analytes with a two-component mixture of organic solvents from weak acidic phosphate buffer solution, concentration of obtained extracts, degreasing and reconstitution with the mobile phase. The use of tandem-mass spectrometric detector in multiple reaction monitoring mode provides high specificity for all ten sulfonamides, which molecules contain the same structural elements, and trimethoprim, as three ion transitions were used for each of the target analytes. The approach of matrix matched calibration on the milk matrix was applied, and it allowed us to disregard taking into consideration the absolute extraction of analytes during sample preparation, as well as the influence of sample matrix components on analytes ionization. The main advantages of the developed technique are simplicity, rapidity and cost effective sample preparation, fast procedure of sample analysis (the time of chromatographic separation is 2.0 min), high selectivity, and sensitivity at the level of ≤ 0.5 μg/kg (as compared with the maximum residues level of sulfonamides in dairy products, viz. 100 μg/kg). According to the European Commission Decision 2002/657/EC, the values of CCα and CCβ for sulfonamides and trimethoprim in milk were calculated. The capability of the method was confirmed on the basis of the established validation parameters, using spiked milk samples and "added – found" approach. The method was tested during the analysis of spiked samples of whole and powdered cow's milk (CV ~ 20%). The developed technique was verified by interlaboratory comparative testing of milk powder samples for sulfonamides content. The UPLC-MS/MS method for the determination of sulfonamides and trimethoprim residues in whole and milk powder samples can be used both for routine laboratory analysis of dairy products and for the examination of suspicious or questionable samples.

Determination of Bisphenol A in Milk and Dairy Products by High-Performance Liquid Chromatography with Fluorescence Detection

2003 ◽  
Vol 66 (8) ◽  
pp. 1439-1443 ◽  
Author(s):  
JEONG-HUN KANG ◽  
FUSAO KONDO
Keyword(s):  
Bisphenol A ◽  
Dairy Products ◽  
High Performance ◽  
Solid Phase ◽  
Skim Milk ◽  
The European Union ◽  
Condensed Milk ◽  
Oasis Hlb ◽  
Milk And Dairy Products

This study was conducted to develop a selective and sensitive method for the determination of bisphenol A (BPA) levels in milk and dairy products. A method based on solvent extraction with acetonitrile and solid-phase extraction (SPE) was developed for the analysis of BPA in milk, yogurt, cream, butter, pudding, condensed milk, and flavored milk, and a method using two SPE cartridges (OASIS HLB and Florisil cartridge) for skim milk was also developed. The developed methods showed good recovery levels (77 to 102%) together with low detection limits (1 μg/liter for milk, yogurt, pudding, condensed milk, flavored milk, and skim milk and 3 μg/liter for cream and butter). These methods are simple, sensitive, and suitable for the analysis of BPA in milk and dairy products. When 40 milk and dairy products were analyzed by the proposed methods, BPA was not identified in noncanned products, but its levels ranged from 21 to 43 μg/kg in canned products, levels that were 60- to 140-fold lower than the migration limits in the European Union and Japan.

Determination of the minimum suppressive concentration of photosensitizers of the second generation in relation to sanitaryindicative microorganisms

2021 ◽  
Vol 1 (11) ◽  
pp. 42-46
Author(s):  
Vadim Yu. Shlenskiy ◽  
◽  
Tatiana I. Pashnik ◽  
Svetlana Yu. Pigina ◽  
◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Salmonella Enteritidis ◽  
Second Generation ◽  
Research Work ◽  
Protoporphyrin Ix ◽  
Bactericidal Effect ◽  
Disodium Salt ◽  
Bacterial Cultures

In the studies described in the article, the presence of antimicrobial activity in photosensitizers in experiments on bacterial cultures was confirmed. In the experiments, photosensitizers of the second generation were used: «Photoditazine», the active substance of which is dimeglumin chloride E6, and «Dimegin», which includes a derivative of protoporphyrin IX-2,4-di(1-methoxyethyl)- deuteroporphyrin IX disodium salt. In the described research work, the minimum concentrations of the studied drugs were determined by the method of sequential tenfold dilutions to obtain a bactericidal effect on strains of sanitary-indicative microorganisms Enterococcus faecalis, Staphylococcus aureus, Salmonella enteritidis.

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