Determination of nitrite in cheese and other dairy products

1972 ◽  
Vol 39 (1) ◽  
pp. 89-94 ◽  
Author(s):  
C. G. Rammell ◽  
M. M. Joerin
Keyword(s):  
Uv Irradiation ◽  
Spectrophotometric Method ◽  
Dairy Products ◽  
Raw Milk ◽  
Spectrofluorimetric Method

SummaryDetails are given of a spectrophotometric method for determining nitrite in cheese and other dairy products at levels down to 0·05 μg NO2-N/g and of a spectrofluorimetric method for levels down to 0·003 μg NO2-N/g. Nitrite-N levels in cheese varied from 0·003 μg/g to 0·021 μg/g. These levels increased up to 4-fold after UV irradiation of the cheese extracts. No nitrite (< 0·003 μg/ml) could be detected in raw milk.

Sensitive Colorimetric Determination of Cholesterol in Dairy Products

1976 ◽  
Vol 59 (5) ◽  
pp. 1146-1149 ◽  
Author(s):  
Kermit C Bachman ◽  
Jan-Hai Lin ◽  
Charles J Wilcox
Keyword(s):  
Dairy Products ◽  
Skim Milk ◽  
Raw Milk ◽  
Colorimetric Determination ◽  
Hexane Extraction ◽  
Color Development ◽  
Fat Extraction ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract Cholesterol can be determined colorimetrically in dairy products at levels of ≥10 μg (coefficient of variation = 5.3%) with an o-phthalaldehyde reagent when non-cholesterol lipids arc eliminated prior to color development. Absorbance for 2 mg tripalmitin was found to be equivalent to about 20 μg cholesterol. Saponification followed by hexane extraction removed interfering lipids. Using the described procedure, 238 individual raw milk samples were found to contain 144.4±37.9 μg cholesterol/ml, while their skim milk portions had 26.5±6.4 μg cholesterol/ml (mean ± standard deviation). The o-phthalaldehyde cholesterol estimates agreed with those obtained by a gas-liquid chromatographic procedure when cheese and ice cream were analyzed by the colorimetric procedure with and without prior fat extraction.

Fluorometric Determination of Alkaline Phosphatase in Fluid Dairy Products: Collaborative Study

1990 ◽  
Vol 73 (6) ◽  
pp. 842-849 ◽  
Author(s):  
Richard M Rocco
Keyword(s):  
Alkaline Phosphatase ◽  
Dairy Products ◽  
Collaborative Study ◽  
Skim Milk ◽  
Raw Milk ◽  
Chocolate Milk ◽  
Phenyl Phosphate ◽  
Whole Milk ◽  
Standard Deviations

Abstract Official methods for the measurement of alkaline phosphatase (ALP) in dairy products use either phenyl phosphate or phenolphthaleln monophosphate as substrate. Quantitation of results requires butanol extraction of the Indophenol (Scharer) or 3-h dialysis of the liberated phenolphthaleln (Rutgers). The Advanced Fluorophos® assay Is based on a self-indicating substrate which, when acted upon by ALP, loses a phosphate radical and becomes a highly fluorescent compound. The rate of fluorophore formation Is monitored for 3 mln In a fluorometer and the enzyme activity In mU/L Is calculated. Eight laboratories participated in a collaborative study to evaluate the Fluorophos® assay for determining ALP activity In whole milk, skim milk, chocolate milk, and cream (half and half). The comparative method was the AOAC quantitative phenyl phosphate method, 16.121-16.122 (14th Ed.). Mixed herd raw milk was added to pasteurized samples at 0.05, 0.1, and 0.2% (v/v). Method performance at 0.1% (v/v) added raw milk as measured by repeatability and reproducibility standard deviations (sr and sR) and relative standard deviations (RSDr and RSDR), respectively, were: whole milk, sr = 21.7%, sR = 34.6%, RSDr = 4.4%, RSDR = 7.0%; skim milk, sr = 19.2%, sR = 31.4%, RSDr = 3.8%, RSDR = 6.2%; chocolate milk, sr = 27.6%, sR = 45.8%, RSDr = 5.3%, RSDR = 8.8%. The method has been adopted official first action by AOAC for determination of alkaline phosphatase in whole milk, skim milk, and chocolate milk.

The Study of Raw Milk Quality Control

2013 ◽  
Vol 411-414 ◽  
pp. 2417-2422
Author(s):  
Yao Li Zhang ◽  
Jing Chen ◽  
Xin Zhong
Keyword(s):  
Dairy Products ◽  
Detection Method ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Test Methods ◽  
Milk Quality ◽  
Living Standard ◽  
Practical Consideration ◽  
Key Points

Now, along with the improvement of people's living standard, more and more people quality safety problems of dairy products by the attention. Milk quality index basically has sensory indexes and physiochemical index, microbiological quality and harmful material residues and pollutants quantity four aspects. Regarding the enterprise, it wants to produce milk, besides should assured teaches defend in production of various indexes; outside the control of raw also cannot be ignored. The key points to control of raw comparison of raw index are to ensure effective method.In recent years, as environmental pollution increasingly heavier, antibiotics, making the wrong use already slowly pollution to harmful material variety of dairy products, in the milk antibiotic and heavy metal content has become the focus of people are indexes. First, in this paper introduces dairy products can exist of antibiotic types and the detection method, then to mercury as example, the paper introduces the current national state currently can several methods of determination of mercury, through the practical consideration, find a relatively simple, efficient, feasibility big test methods.

scholarly journals Comparative analysis of the effectiveness of analytical methods for the determination of aflatoxins in milk and dairy products (review information)

2020 ◽  
pp. 150-157
Author(s):  
S. Senin ◽  
V. Danchuk ◽  
S. Midyk ◽  
V. Ushkalov ◽  
O. Iakubchak
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Sample Preparation ◽  
Analytical Methods ◽  
Dairy Products ◽  
High Performance ◽  
Raw Milk ◽  
Enzyme Linked Immunosorbent Assay ◽  
Milk And Dairy Products

The dairy industry of Ukraine is developing dynamically, its needs for the quality of raw materials are growing significantly. Detection of mycotoxins in raw milk is one of the main indicators of its safety. The high degree of toxicity of mycotoxins is a threat to the health of the lactating animal, so a large number of them are excreted in milk. If we talk about ruminants, the vast majority of mycotoxins are utilized by microorganisms of the pancreas, which does not occur in monogastric animals, so the list of mycotoxins in their milk can be much wider than the secretion of mammalian mammals. To date, the maximum permissible levels (MRLs) of mycotoxins in raw milk and dairy products have been established. Thus, a comprehensive determination of the content of mycotoxins in the secretion of the breast has not only technological but also important diagnostic value. Milk sample preparation is the most important step in the determination of mycotoxins and consists of sampling, extraction and purification from impurities. For the extraction of aflatoxins, the method of liquid extraction with acetonitrile or chloroform is used. Purification of extracts is carried out on immunoaffinity columns, cartridges with special sorbents or using certain manufacturers (MycoSep®).Enzyme-linked immunosorbent assay and high-performance liquid chromatography with fluorescence detection are used to determine aflatoxin B1 and M1 in raw milk of cows. However, all these methods have a number of disadvantages, namely: long and expensive sample preparation and insufficiently high selectivity. Currently, the complex determination of mycotoxins in various matrices by high-performance liquid chromatography with mass spectrometric detection (LC-MS/MS) and the use of modified QuEChERS sample preparation is gaining popularity. The advantage of this technique is the combination of faster and cheaper sample preparation of QuEChERS samples with highly selective LC-MS/MS chromatography. Key words: mycotoxins, raw milk, analytical methods, QuEChERS.

scholarly journals Determination of some metals in the commonly consumed dairy products randomly collected from the market in Alexandria - Egypt, with an emphasis on toxicity, permissible limits and risk assessment

2016 ◽  
Vol 4 (2) ◽  
pp. 133 ◽  
Author(s):  
Sahar Issa ◽  
Doaa Genina ◽  
Maha Al Mazroua ◽  
Safaa Abdel Rahman ◽  
Marwa M Fawzi
Keyword(s):  
Dairy Products ◽  
Inductively Coupled Plasma ◽  
Raw Milk ◽  
Point Of View ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Random Samples ◽  
White Cheese ◽  
Quantitative Analyses

The aim of this research was to evaluate the possible contamination by heavy metals of 30 random samples of raw milk and four other dairy products (pasteurized milk, white cheese, yellow cheese, and yoghurt), that were purchased from the three different regions in Alexandria, Egypt namely; (Eastern, Central and Western Alexandria). Each sample was homogenized, powdered, and mineralized in a microwave oven. Quantitative analyses of Al, Se, Zn, Cd, Cu and Pb were performed using an inductively coupled plasma-mass (ICP-MS) spectrometry. Western Alexandria samples had the highest recorded levels in Pb, Cd and Cu (7.421 ppm, and 0.673 ppm, and 5.013 ppm) consecutively. Highest levels detected for Al and Se were detected in samples collected from Eastern Alexandria (2.74 ppm and 0.093 ppm) successively. Zn (31.64 ppm) showed the highest concentration in a sample purchased from Central Alexandria. Further investigations of the levels of metals in bigger number of milk samples from different zones of Alexandria, Egypt are necessary, both to examine this problem from the toxicological, clinical, and epidemiological point of view and, to assess the exposure risk.

Determination of bovine lactoferrin in lactoferrin-supplemented dairy products and raw milk by an automated latex assay

2006 ◽  
Vol 74 (1) ◽  
pp. 100-105 ◽  
Author(s):  
Takashi Soejima ◽  
Koji Yamauchi ◽  
Tomoko Yamamoto ◽  
Yasuko Ohara ◽  
Eiji Nagao ◽  
...  
Keyword(s):  
Infant Formula ◽  
Dairy Products ◽  
Standard Addition ◽  
Raw Milk ◽  
Bovine Lactoferrin ◽  
Addition Method ◽  
Intermediate Precision ◽  
Uht Milk ◽  
Agglutination Method

Latex immune agglutination method with a multipurpose auto-analyser (the automated latex assay) was validated for determination of bovine lactoferrin (BLF) in various dairy products. Reproducibility-within-laboratory (intermediate precision) due to day for infant formula, UHT milk and yogurt supplemented with BLF at 50 mg/100 g for infant formula and UHT milk, and at 100 mg/100 g for yogurt were 1·62 to 3·10 mg/100 g. Reproducibility-within-laboratory due to analysis (morning, noon, and evening) for raw milk was 1·59 mg/100 g. Trueness, accuracy in determining known amounts added for BLF-supplemented dairy products was −4·7 to −2·0 mg/100 g. BLF concentration in raw milks was 20·3 to 21·8 mg/100 g. Although interference by the matrixes took place in infant formula and raw milk, BLF assays were accurately carried out by 2000-fold dilution or standard-addition method. Automated latex assay for BLF is simple, rapid, precise and accurate enough for a routine method in various dairy products containing BLF.

Spectrophotometric and spectrofluorimetric determination of mesna, acetylcysteine and timonacic acid through the reaction with acetoxymercuri fluorescein

2016 ◽  
Vol 8 (11) ◽  
pp. 2479-2493 ◽  
Author(s):  
Rim S. Haggag ◽  
Dina A. Gawad ◽  
Saeid F. Belal ◽  
Hadil M. Elbardisy
Keyword(s):  
Spectrophotometric Method ◽  
Spectrofluorimetric Method ◽  
Spectrofluorimetric Determination ◽  
Sulfur Containing ◽  
Timonacic Acid

Simple, sensitive and specific spectrophotometric (Method I) and spectrofluorimetric (Method II) methods were developed for the determination of three sulfur-containing drugs: mesna (MSN), acetylcysteine (ACT) and timonacic acid (TMN).

Collaborative Study of a Spectrophotometry Method for the Determination of Sorbic Acid in Fresh Dairy Products

1974 ◽  
Vol 57 (3) ◽  
pp. 675-677 ◽  
Author(s):  
George Wilamowski
Keyword(s):  
Spectrophotometric Method ◽  
Dairy Products ◽  
Sorbic Acid ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Extraction Procedure ◽  
Mozzarella Cheese ◽  
Metaphosphoric Acid ◽  
Cold Pack

Abstract A collaborative study has been completed on the determination of sorbic acid in 2 dairy products by a spectrophotometric method. Mozzarella cheese and cold pack cheese food were analyzed for sorbic acid. The sorbic acid was extracted from the dairy products with metaphosphoric acid and partitioned into a petroleum ether-anhydrous ether mixture. The concentration of sorbic acid was determined from its absorbance at 250 nm and its presence was confirmed by the disappearance of this absorbance maximum after shaking the ether solution with aqueous permanganate. The results obtained in the 10 collaborators’ laboratories were statistically evaluated. The average per cent recovery of sorbic acid in mozzarella cheese was 93.6—95.6 and in cold pack cheese food 90.7—101.9. A comparison was also made between the extraction procedure and the AOAC colorimetric method for sorbic acid in cold pack cheese food. The AOAC method had lower variability and higher per cent recovery for this product. The spectrophotometric method has been adopted as official first action as a screening procedure for sorbic acid in fresh dairy products.

The determination of plasmin and plasminogen-derived activity in turbid samples from various dairy products using an optimised spectrophotometric method

2014 ◽  
Vol 38 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Valentin M. Rauh ◽  
Mette Bakman ◽  
Richard Ipsen ◽  
Marie Paulsson ◽  
Alan L. Kelly ◽  
...  
Keyword(s):  
Spectrophotometric Method ◽  
Dairy Products

Determination of Phosphatase in Dairy Products by Dialysis

1965 ◽  
Vol 48 (4) ◽  
pp. 811-815
Author(s):  
Sam H Perlmutter ◽  
Lossie M Lewis
Keyword(s):  
Dairy Products ◽  
Raw Milk ◽  
Dialysis Technique

Abstract A method for determination of phosphatase, the enzyme naturally present in raw milk, hascd on a dialysis technique, was evaluated by a collahorative test among seven laboratories. Results indicate that the method is accurate and reproducible, and it was adopted as official, first action.

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