Effect of the electro-dialysis treatment temperature on the microflora of skim milk permeate

Pasteurized whole, 2%, and skim milk were inoculated with Listeria monocytogenes Scott A and treated with high-voltage pulsed electric field (PEF). The effects of milk composition (fat content) and PEF parameters (electric field strength, treatment time, and treatment temperature) on the inactivation of the bacterium were studied. No significant differences were observed in the inactivation of L. monocytogenes Scott A in three types of milk by PEF treatment. With treatment at 25°C, 1- to 3-log reductions of L. monocytogenes were observed. PEF lethal effect was a function of field strength and treatment time. Higher field strength or longer treatment time resulted in a greater reduction of viable cells. A 4-log reduction of the bacterium was obtained by increasing the treatment temperature to 50°C. Results indicate that the use of a high-voltage PEF is a promising technology for inactivation of foodborne pathogens.

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Modelling formation and removal of biofilms in secondary dairy raw materials

Foods and raw materials ◽

10.21603/2308-4057-2021-1-59-68 ◽

2020 ◽

pp. 59-68

Author(s):

Svetlana Ryabtseva ◽

Yulia Tabakova ◽

Andrey Khramtsov ◽

Georgy Anisimov ◽

Vitalii Kravtsov

Keyword(s):

Glass Surface ◽

Raw Materials ◽

Dairy Industry ◽

Skim Milk ◽

Whey Permeate ◽

Biofilm Growth ◽

Sweet Whey ◽

Acid Whey ◽

Skimmed Milk ◽

Milk Permeate

Introduction. Microorganisms of dairy raw materials tend to adhere to the surfaces of processing equipment and form sustainable biofilms, which is a serious issue in the dairy industry. The goal of the present work was to investigate formation of biofilms on a glass surface in static model conditions, and removal of such biofilms by cleaning. Study objects and methods. The study objects were the permeates of skim milk, sweet whey and acid whey, as well as the biofilms formed and washings from glass slides. Biofilms were removed from the glass with detergents used in the dairy industry. Standard methods of determining microbiological and physicochemical properties were used to characterize the permeates. The biofilm structure and morphology of microorganisms participating in biofilm formation were investigated with a light spectroscopy. The efficiency of biofilm removal in a cleaning process was quantified with optical density of washings. Results and discussion. Biofilms in whey permeates formed slower compared to those in skimmed milk permeate during the first 24 h. Yeasts contributed significantly to the biofilm microflora in acid whey permeate throughout 5 days of biofilm growth. Well adhered biofilm layers were the most stable in skimmed milk permeate. The highest growth of both well and poorly adhered biofilm layers was observed in sweet whey permeate after 3–5 days. It was established that the primary attachment of microorganisms to a glass surface occurred within 8 h, mature multicultural biofilms formed within 48 h, and their partial destruction occurred within 72 h. Conclusion. The research results can be used to improve the cleaning equipment procedures in processing secondary dairy raw materials.

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The use of skim milk permeate in the preparation of spray dried beverages II. Beverage based on Strawberry

European Food Research and Technology ◽

10.1007/bf02425583 ◽

1985 ◽

Vol 181 (3) ◽

pp. 223-225 ◽

Cited By ~ 1

Author(s):

S. El-Shibiny ◽

M. H. Abd El-Salam ◽

M. B. Mahfouz ◽

H. El-Etriby

Keyword(s):

Skim Milk ◽

Milk Permeate ◽

Spray Dried

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Inactivation of Pseudomonas fluorescens in Skim Milk by Combinations of Pulsed Electric Fields and Organic Acids

Journal of Food Protection ◽

10.4315/0362-028x-68.6.1232 ◽

2005 ◽

Vol 68 (6) ◽

pp. 1232-1235 ◽

Cited By ~ 16

Author(s):

JUAN J. FERNÁNDEZ-MOLINA ◽

BILGE ALTUNAKAR ◽

DANIELA BERMÚDEZ-AGUIRRE ◽

BARRY G. SWANSON ◽

GUSTAVO V. BARBOSA-CÁNOVAS

Keyword(s):

Acetic Acid ◽

Organic Acids ◽

Pseudomonas Fluorescens ◽

Propionic Acid ◽

Electric Fields ◽

Skim Milk ◽

Pulsed Electric Fields ◽

Treatment Temperature ◽

Initial Concentration ◽

Ph Range

Pseudomonas fluorescens suspended in skim milk was inactivated by application of pulsed electric fields (PEF) either alone or in combination with acetic or propionic acid. The initial concentration of microorganisms ranged from 105 to 106 CFU/ml. Addition of acetic acid and propionic acid to skim milk inactivated 0.24 and 0.48 log CFU/ml P. fluorescens, respectively. Sets of 10, 20, and 30 pulses were applied to the skim milk using exponentially decaying pulses with pulse lengths of 2 μs and pulse frequencies of 3 Hz. Treatment temperature was maintained between 16 and 20°C. In the absence of organic acids, PEF treatment of skim milk at field intensities of 31 and 38 kV/cm reduced P. fluorescens populations by 1.0 to 1.8 and by 1.2 to 1.9 log CFU/ml, respectively. Additions of acetic and propionic acid to the skim milk in a pH range of 5.0 to 5.3 and PEF treatment at 31, 33, and 34 kV/cm, and 36, 37, and 38 kV/cm reduced the population of P. fluorescens by 1.4 and 1.8 log CFU/ml, respectively. No synergistic effect resulted from the combination of PEF with acetic or propionic acid.

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The impact of protein standardisation with liquid or powdered milk permeate on the rheological properties of skim milk concentrates

International Dairy Journal ◽

10.1016/j.idairyj.2021.104982 ◽

2021 ◽

pp. 104982

Author(s):

Paraskevi Tsermoula ◽

Kamil P. Drapala ◽

Aoife M. Joyce ◽

Kate Hoare ◽

Shane V. Crowley ◽

...

Keyword(s):

Rheological Properties ◽

Skim Milk ◽

Powdered Milk ◽

Milk Permeate ◽

The Impact

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Heat Resistance of Bacillus cereus Spores: Effects of Milk Constituents and Stabilizing Additives

Journal of Food Protection ◽

10.4315/0362-028x-62.4.410 ◽

1999 ◽

Vol 62 (4) ◽

pp. 410-413 ◽

Cited By ~ 16

Author(s):

MARGARITA MAZAS ◽

MERCEDES LÓPEZ ◽

SIDONIA MARTÍNEZ ◽

ANA BERNARDO ◽

ROBERTO MARTIN

Keyword(s):

Heat Resistance ◽

Bacillus Cereus ◽

Sodium Citrate ◽

Ph Effect ◽

Skim Milk ◽

Milk Composition ◽

Treatment Temperature ◽

Monopotassium Phosphate ◽

The Difference ◽

D Values

Heat resistance of Bacillus cereus spores (ATCC 7004, 4342, and 9818) heated in different types of milk (skim, whole, and concentrated skim milk), skim milk containing stabilizing additives (sodium citrate, monopotassium phosphate, or disodium phosphate, 0.1%), and cream was investigated. Thermal resistance experiments were performed at temperatures within the range of 92 to 115°C under continuous monitoring of pH. For strain 4342 no significant differences (P < 0.05) in D values were detected in any case. For strains 7004 and 9818 higher D values of about 20% were obtained in whole and concentrated skim milk than those calculated in skim milk. From all stabilizing additives tested, only sodium citrate and sodium phosphate increased the heat resistance for strain 9818. However, when the menstruum pH was measured at the treatment temperature, different pH values were found between the heating media. The differences in heat resistance observed could be due to a pH effect rather than to the difference in the substrates in which spores were heated. In contrast, when cream (fat content 20%) was used, lower D values were obtained, especially for strains 7004 and 9818. z values were not significantly modified by the milk composition, with an average z value of 7.95 ± 0.20°C for strain 7004, 7.88 ± 0.10°C for strain 4342, and 9.13 ± 0.16°C for strain 9818.

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Compositional and Functional Characteristics of Feta-Type Cheese Made from Micellar Casein Concentrate

Foods ◽

10.3390/foods11010024 ◽

2021 ◽

Vol 11 (1) ◽

pp. 24

Author(s):

Ahmed R. A. Hammam ◽

Rohit Kapoor ◽

Prafulla Salunke ◽

Lloyd E. Metzger

Keyword(s):

Protein Content ◽

Whey Proteins ◽

Skim Milk ◽

Compositional Analysis ◽

Sodium Chloride Solutions ◽

Whole Milk ◽

Soft Cheese ◽

Micellar Casein ◽

Milk Permeate ◽

Mixing Water

Micellar casein concentrate (MCC) is a high protein ingredient (obtained by microfiltration of skim milk) with an elevated level of casein as a percentage of total protein (TP) compared to skim milk. It can be used as an ingredient in cheese making. Feta-type cheese is a brined soft cheese with a salty taste and acid flavor. We theorize that Feta-type cheese can be produced from MCC instead of milk, which can improve the efficiency of manufacture and allow for the removal of whey proteins before manufacturing Feta-type cheese. The objectives of this study were to develop a process of producing Feta-type cheese from MCC and to determine the optimum protein content in MCC to make Feta-type cheese. MCC solutions with 3% (MCC-3), 6% (MCC-6), and 9% (MCC-9) protein were prepared and standardized by mixing water, MCC powder, milk permeate, and cream to produce a solution with 14.7% total solids (TS) and 3.3% fat. Thermophilic cultures were added at a rate of 0.4% to MCC solutions and incubated at 35 °C for 3 h to get a pH of 6.1. Subsequently, calcium chloride and rennet were added to set the curd in 20 min at 35 °C. The curd was then cut into cubes, drained for 20 h followed by brining in 23% sodium chloride solutions for 24 h. Compositional analysis of MCC solutions and cheese was carried out. The yield, color, textural, and rheological measurements of Feta-type cheese were evaluated. Feta-type cheese was also made from whole milk as a control. This experiment was repeated three times. The yield and adjusted yield of Feta-type cheese increased from 19.0 to 54.8 and 21.4 to 56.5, respectively, with increasing the protein content in MCC from 3% to 9%. However, increasing the protein content in MCC did not show significant differences in the hardness (9.2–9.7 kg) of Feta-type cheese. The color of Feta-type cheese was less white with increasing the protein content in MCC. While the yellowish and greenish colors were high in Feta-type cheese made from MCC with 3% and 6% protein, no visible differences were found in the overall cheese color. The rheological characteristics were improved in Feta-type cheese made from MCC with 6% protein. We conclude that MCC with different levels of protein can be utilized in the manufacture of Feta-type cheese.

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