Low Salt Soft Cheese; Compositional Quality and Incidence of Aerobic Spore Forming Bacteria

2020 ◽  
Vol 66 (2) ◽  
pp. 48
Author(s):  
Ashraf Nazem ◽  
Sameh Awad ◽  
Eman Shaala
Keyword(s):  
Soft Cheese ◽  
Low Salt ◽  
Compositional Quality ◽  
Spore Forming Bacteria

scholarly journals Application of Natural Antimicrobial Additives and Protective Culture to Control Aerobic Spore Forming Bacteria in Low Salt Soft Cheese

2020 ◽  
Vol 10 (4) ◽  
pp. 609-616
Author(s):  
Eman K. Abo Shaala ◽  
Sameh A. Awad ◽  
Ashraf M. Nazem
Keyword(s):  
Antimicrobial Agents ◽  
Lactobacillus Rhamnosus ◽  
Microbiological Quality ◽  
Storage Period ◽  
Life Extension ◽  
Natural Antimicrobial ◽  
Soft Cheese ◽  
Low Salt ◽  
Protective Culture ◽  
Spore Forming Bacteria

There is an increasing interest in the application of natural antimicrobials instead of chemical ones to enhance the microbiological quality of dairy products. The objective of this study was to assess the effect of some natural antimicrobial additives and protective culture for reducing the usage of chemical preservatives, shelf-life extension, retarding microbial spoilage in low-salt soft cheese. The antimicrobial agents (protective culture, nisin, lysozyme, and natamycin) were studied on the activity of 28 isolates of spore-forming bacteria. Inhibitory effect of different natural antimicrobial additives as protective culture (Lactobacillus rhamnosus, 40 mg kg -1), nisin (25 mg kg -1), lysozyme (100 mg kg -1), combination of nisin and lysozyme (25 mg kg -1/100 mg kg -1), and combination of protective culture and natamycin (40 mg kg -1/25 mg kg -1) were studied on the growth of aerobic spore-forming bacteria in low-salt soft cheese during the storage period (30 days) at 4±1°C. The results revealed that the addition of different natural antibacterial additives with various concentrations had a significant effect on aerobic spore-forming bacteria, compared to other treatments and control. The growth pattern of aerobic spore-forming bacteria gradually decreased in all treatments along the storage period with variable reduction percentages in comparison with control cheese which was in continuous increment. The application of a combination of nisin and lysozyme had the most significant reduction of aerobic spore-forming bacteria, compared to control and other treatments.

scholarly journals Inhibitory activity of some functional cultures toward common microbial contaminants in soft cheese manufactured from raw milk

2020 ◽  
Vol 6 (10) ◽  
pp. 43-49
Author(s):  
Ahmed M. M. Mabrouk
Keyword(s):  
Inhibitory Activity ◽  
Storage Period ◽  
Raw Milk ◽  
Fecal Coliforms ◽  
Control Treatment ◽  
Total Coliforms ◽  
Soft Cheese ◽  
Microbial Contaminants ◽  
Microbial Groups ◽  
Spore Forming Bacteria

The inhibitory activity of Lb. plantarum NRC AM10, Lb. curvatus NBIMCC 3452, Lb. paracasei NRRL B-4560 and Lb. gasseri NRRL B-14168 were investigated against the microbial contaminants in raw milk soft cheese. Cultures were added at the level of 5 % in T1, T2, T3 and T4 respectively, and the control treatment made without starters. Microbial counts in raw milk sample showed 10.25, 6.85, 5.89, 4.76, 4.42, 4.44, 3.77, 3.64 and 3.46 log cfu/ml for total viable count, total coliforms, Staphylococci, moulds and yeasts, Enterococci, fecal coliforms, spore forming bacteria, psychrotrophic and Salmonella respectively. Some of microbial groups in control cheese were increased in the first 5 days of storage and others were increased until 10 days then all microbial groups were gradually decreased with extending storage period. Staphylococci reached to the lowest counts 3.11 log cfu/ml after 20 days, on contrast moulds and yeasts reached to the highest count 5.22 log cfu/ml at the end of storage period. The inhibition rate % (IR) were influenced by the variety of strain added in cheese treatments and the highest IR 32.58 and 33.96 % against total coliforms and Enterococci were recorded in the treatment containing Lb. plantarum NRC AM10 while the highest IR 25.84 % against fecal coliforms was recorded in the treatment containing Lb. curvatus NBIMCC 3452. Meanwhile, the IR 35.19 and 15.84 % were recorded against Salmonella and spore forming bacteria with strain Lb. gasseri NRRL B-14168. The strain Lb. paracasei NRRL B-4560 showed IR 42.23 and 44.4 % against Staphylococci and psychrotrophic respectively. Moulds and yeasts talked a revers trend of IR because of increasing the counts by acidity development. In conclusion, the only addition of functional cultures to control the growth and survival of pathogens in raw milk products is not enough to produce safe product. Use of pasteurized milk, good hygienic and good manufacturing practices are essential to reduce the risk of microbial contamination and health hazards in dairy products.

scholarly journals Nigella sativa oil: A promising prospective antifungal agent in the manufacture of low-salt soft cheese

2021 ◽  
Vol 10 (4) ◽  
Author(s):  
Eman F. Abdel-Latif ◽  
Khaled A. Abbas ◽  
Hani S. Abdelmontaleb ◽  
Shaimaa M. Hamdy
Keyword(s):  
Candida Albicans ◽  
Antifungal Activity ◽  
Physicochemical Properties ◽  
Aspergillus Parasiticus ◽  
Nigella Sativa ◽  
Nigella Sativa Oil ◽  
Soft Cheese ◽  
Low Salt ◽  
Sensorial Evaluation

The current work studied the in-vivo antifungal activity of Nigella sativa oil (NSO) in ultrafiltered low-salt soft cheese as a proposed replacement for the synthetic preservatives which become unacceptable by consumers. Four different concentrations of NSO were examined during the manufacture of the cheese (0.3, 0.5, 1, and 3 % w/w). The effect of NSO supplementation was examined in 3 parallel lines; a ninepoint hedonic scale was used in the sensorial evaluation of soft cheese free of the fungal inoculum, the physicochemical properties of soft cheese were determined during storage as well as anti-fungal effects of different concentrations of NSO on inoculated cheese with different species of fungi: Candida albicans (104 cfu/ml) and Aspergillus parasiticus (102 cfu/ml) before coagulation. The Nigella sativa oil expressed an antifungal activity by using different levels of NSO which significantly reduced and inhibited the growth of the fungal counts (1.4 log cfu/g for Candida albicans and 2.30 log cfu/g for Aspergillus parasiticus) started from 0.5% concentration of NSO on the 14th day of the storage. In addition, it exhibited different physicochemical properties of soft cheese depending on the level of used NSO. However, the Sensory evaluation of cheese samples revealed the acceptance of soft cheese samples with 0.3% and 0.5% of NSO.

Ultrastructural localization of specific nucleoprotein fractions

1978 ◽  
Vol 36 (2) ◽  
pp. 204-205
Author(s):  
G. L. Brown
Keyword(s):  
Gel Electrophoresis ◽  
Mouse Liver ◽  
Polyacrylamide Gel Electrophoresis ◽  
Ultrastructural Localization ◽  
Polyacrylamide Gel ◽  
Acid Extraction ◽  
Acid Solutions ◽  
Low Salt ◽  
Liver Nuclei ◽  
Phosphate Groups

Bismuth (Bi) stains nucleoproteins (NPs) by interacting with available amino and primary phosphate groups. These two staining mechanisms are distinguishable by glutaraldehyde crosslinking (Fig. 1,2).Isolated mouse liver nuclei, extracted with salt and acid solutions, fixed in either formaldehyde (form.) or gl utaraldehyde (glut.) and stained with Bi, were viewed to determine the effect of the extractions on Bi stainina. Solubilized NPs were analyzed by SDS-polyacrylamide gel electrophoresis.Extraction with 0.14 M salt does not change the Bi staining characteristics (Fig. 3). 0.34 M salt reduces nucleolar (Nu) staining but has no effect on interchromatinic (IC) staining (Fig. 4). Proteins responsible for Nu and glut.- insensitive IC staining are removed when nuclei are extracted with 0.6 M salt (Fig. 5, 6). Low salt and acid extraction prevents Bi-Nu staining but has no effect on IC staining (Fig. 7). When nuclei are extracted with 0.6 M salt followed by low salt and acid, all Bi-staining components are removed (Fig. 8).

Surfactant Impurities Can Explain the Jones-Ray Effect

2018 ◽  
Author(s):  
Timothy Duignan ◽  
Marcel Baer ◽  
Christopher Mundy
Keyword(s):  
Surface Tension ◽  
Electrostatic Potential ◽  
Driving Forces ◽  
Salt Water ◽  
Fundamental Property ◽  
Apparent Contradiction ◽  
Low Salt ◽  
Air Water Interface ◽  
Added Salt ◽  
Effect Of Surface

<div> <p> </p><div> <div> <div> <p>The surface tension of dilute salt water is a fundamental property that is crucial to understanding the complexity of many aqueous phase processes. Small ions are known to be repelled from the air-water surface leading to an increase in the surface tension in accordance with the Gibbs adsorption isotherm. The Jones-Ray effect refers to the observation that at extremely low salt concentration the surface tension decreases in apparent contradiction with thermodynamics. Determining the mechanism that is responsible for this Jones-Ray effect is important for theoretically predicting the distribution of ions near surfaces. Here we show that this surface tension decrease can be explained by surfactant impurities in water that create a substantial negative electrostatic potential at the air-water interface. This potential strongly attracts positive cations in water to the interface lowering the surface tension and thus explaining the signature of the Jones-Ray effect. At higher salt concentrations, this electrostatic potential is screened by the added salt reducing the magnitude of this effect. The effect of surface curvature on this behavior is also examined and the implications for unexplained bubble phenomena is discussed. This work suggests that the purity standards for water may be inadequate and that the interactions between ions with background impurities are important to incorporate into our understanding of the driving forces that give rise to the speciation of ions at interfaces. </p> </div> </div> </div> </div>

Soft cheese from the mixture of cow and goat milks with addition of nut flour.

2018 ◽  
pp. 30-32
Author(s):  
A.Yu. Chechetkina ◽  
◽  
L.A. Zabodalova ◽  
Keyword(s):  
Soft Cheese
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