Evaluation of Spectrophotometric and Fluorometric Methods for Alkaline Phosphatase Activity Determination in Ewe's Milk

2000 ◽  
Vol 63 (9) ◽  
pp. 1258-1261 ◽  
Author(s):  
M. F. SCINTU ◽  
E. DAGA ◽  
A. LEDDA
Keyword(s):  
Alkaline Phosphatase ◽  
Standard Deviation ◽  
Raw Milk ◽  
Cow’S Milk ◽  
Official Method ◽  
Cow's Milk ◽  
Alp Activity ◽  
Relative Standard ◽  
Ewe's Milk ◽  
European Method

The alkaline phosphatase (ALP) activity test has been used since 1935 to assess the effectiveness of pasteurization. Different analytical methods exist for detecting ALP in milk. Unfortunately, there is little information about ALP activity in ewe's milk. The aim of this study was to assess and compare the official European method (spectrophotometric method) and the Fluorophos method (fluorometric method) regarding their use in ewe's milk. Bulk ewe's milk samples were taken from a flock and from three different dairies. A portion of the original sample was pasteurized at 63°C for 30 min in a circulating bath; another portion was heated to and kept at 95°C for about 2 min, and 0.1% (vol/vol) of raw milk was added. The samples obtained were analyzed in duplicate using the spectrophotometric and fluorometric methods. The relation between ALP activity determined by the two methods was characterized by the following equation: Y = 1.34 + 0.0039X (where Y = ALP in μg of phenol per ml of milk and X = ALP in mU/liter; R2 = 91.5%). Precision parameters (repeatability [r], standard deviation of repeatability [sr], and relative standard deviation of repeatability [RSDr]) for both methods were calculated. The values of RSDr for the Fluorophos method were 4.30 for pasteurized milk and 2.96 for 0.1% raw milk, close to the value indicated by Rocco in whole cow's milk (RSDr = 4.4). The repeatability for the official method (r = 2.16) was close to that indicated for whole cow's milk (r = 2).

Assessment of the Colorimetric and Fluorometric Assays for Alkaline Phosphatase Activity in Cow's, Goat's, and Sheep's Milk

2008 ◽  
Vol 71 (9) ◽  
pp. 1884-1888 ◽  
Author(s):  
V. KLOTZ ◽  
ART HILL ◽  
K. WARRINER ◽  
M. GRIFFITHS ◽  
J. ODUMERU
Keyword(s):  
Alkaline Phosphatase ◽  
Colorimetric Assay ◽  
Residual Activity ◽  
Raw Milk ◽  
The United States ◽  
Cow’S Milk ◽  
Human Pathogens ◽  
Cow's Milk ◽  
Limit Of Quantitation ◽  
Time Required

Raw milk is a well-established vehicle for the carriage of human pathogens, and many regulatory bodies have consequently mandated compulsory pasteurization as a food safety intervention. The residual activity of alkaline phosphatase (ALP) has historically been used to verify the adequacy of pasteurization of cow's milk. However, there is uncertainty on how the current ALP standards and methods of analysis can be applied to sheep's and goat's milk, which naturally contain different levels of the enzyme than that found in cow's milk. The official ALP methods applied in Canada (colorimetric assay; MFO-3) and in the United States (Fluorophos) were assessed for their ability to detect enzyme activity in raw and pasteurized milk derived from cows, sheep, and goats. The detection limit and the limit of quantitation were 0.8 and 2.02 μg/ml phenol, respectively, for the MFO-3 method and 43 and 85 mU/liter, respectively, for the Fluorophos method. The average ALP levels in raw goat's, cow's, and sheep's milk were 165, 1,562, and 3,512 μg/ml phenol, respectively. Raw milk detection limits, which correspond to raw milk phosphatase levels, were 0.051, 0.485, and 0.023% in cow's, goat's, and sheep's milk, respectively, for the MFO-3 method and 0.007, 0.070, and 0.004%, respectively, for the Fluorophos method. Although both methods can be used for ALP determination in cow's, goat's, and sheep's milk, the Fluorophos assay was superior to the colorimetric MFO-3 method based on sensitivity and time required to complete the analysis.

Collaborative Evaluation of a Fluorometric Method for Measuring Alkaline Phosphatase Activity in Cow's, Sheep's, and Goat's Milk

2005 ◽  
Vol 68 (5) ◽  
pp. 1047-1053 ◽  
Author(s):  
FRANK HARDING ◽  
EILEEN GARRY
Keyword(s):  
Alkaline Phosphatase ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Dairy Products ◽  
Test System ◽  
Plant Performance ◽  
Alp Activity ◽  
Goat’S Milk ◽  
Relative Standard ◽  
Goat's Milk

Pasteurization of raw milk was introduced to extend product shelf life and destroy pathogens. The measurement of alkaline phosphatase (ALP) activity has been used as an indicator of proper pasteurization in dairy products for more than 65 years. This study was undertaken to evaluate six different fluid dairy products at lower phosphatase levels than previously verified using the Fluorophos Test System, a sensitive and precise method for ALP activity detection. Thirteen laboratories participated in this collaborative, international study to evaluate the fluorometric test at 20, 40, 100, 350, and 500 mU/liter and extend the scope of the method to include milk from not only cows but also goats and sheep. Initially, the statutory level of ALP measured fluorometrically was set to equivalent levels of colorimetric test standards (500 mU/liter). The European Union recently announced its intention of lowering the legal limit from 500 to 350 mU/liter and, in addition, setting a target value of 100 mU/liter, which if exceeded would trigger an investigation into the pasteurizer plant performance. At 500 mU/liter of ALP, this trial generated relative standard deviation of repeatability values of 6.48, 5.69, and 1.74% and relative standard deviation of reproducibility values of 14.66, 13.30, and 5.33% for all cow's, sheep's, and goat's milk samples, respectively. Data from this study are comparable to data from previous studies and indicate the suitability of the Fluorophos Test System method for measuring ALP activity in milk from cows, sheep, and goats not only at the current European statutory level of 500 mU/liter but also at much lower levels.

scholarly journals Suppression of Food Allergic Symptoms by Raw Cow’s Milk in Mice is Retained after Skimming but Abolished after Heating the Milk—A Promising Contribution of Alkaline Phosphatase

Nutrients ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1499 ◽  
Author(s):  
Suzanne Abbring ◽  
Joseph Thomas Ryan ◽  
Mara A.P. Diks ◽  
Gert Hols ◽  
Johan Garssen ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Protective Effect ◽  
Raw Milk ◽  
Fat Content ◽  
Cow’S Milk ◽  
Protective Effects ◽  
Pasteurized Milk ◽  
Cow's Milk ◽  
Allergic Symptoms ◽  
Raw Cow’S Milk

Raw cow’s milk was previously shown to suppress allergic symptoms in a murine model for food allergy. In the present study, we investigated the contribution of fat content and heat-sensitive milk components to this allergy-protective effect. In addition, we determined the potency of alkaline phosphatase (ALP), a heat-sensitive raw milk component, to affect the allergic response. C3H/HeOuJ mice were treated with raw milk, pasteurized milk, skimmed raw milk, pasteurized milk spiked with ALP, or phosphate-buffered saline for eight days prior to sensitization and challenge with ovalbumin (OVA). Effects of these milk types on the allergic response were subsequently assessed. Similar to raw milk, skimmed raw milk suppressed food allergic symptoms, demonstrated by a reduced acute allergic skin response and low levels of OVA-specific IgE and Th2-related cytokines. This protective effect was accompanied by an induction of CD103+CD11b+ dendritic cells and TGF-β-producing regulatory T cells in the mesenteric lymph nodes. Pasteurized milk was not protective but adding ALP restored the allergy-protective effect. Not the fat content, but the heat-sensitive components are responsible for the allergy-protective effects of raw cow’s milk. Adding ALP to heat-treated milk might be an interesting alternative to raw cow’s milk consumption, as spiking pasteurized milk with ALP restored the protective effects.

Enumeration and Confirmation of Aeromonas hydrophila, Aeromonas caviae, and Aeromonas sobria Isolated from Raw Milk and Other Milk Products in Northern Greece

1999 ◽  
Vol 62 (5) ◽  
pp. 463-466 ◽  
Author(s):  
DIMITRIOS S. MELAS ◽  
DEMETRIOS K. PAPAGEORGIOU ◽  
ANTONIOS I. MANTIS
Keyword(s):  
Raw Milk ◽  
Cow’S Milk ◽  
Aeromonas Species ◽  
Northern Greece ◽  
Cow's Milk ◽  
Milk Samples ◽  
Aeromonas Sobria ◽  
Aeromonas Caviae ◽  
Feta Cheese ◽  
Ewe's Milk

A total of 138 raw cow's and 57 raw ewe's milk samples; 80 pasteurized cow's milk samples; 39 Anthotyros cheese, 36 Manouri cheese, and 23 Feta cheese samples; and 15 rice pudding samples were examined for the presence and any countable population of Aeromonas species. Twenty-two (15.9%) of the 138 cow's milk samples analyzed were contaminated with A. hydrophila. In 13 of these samples, populations of 3.0 × 102 to 5.0 × 103 CFU/ml were counted in starch ampicillin agar (SAA). Eighteen cow's milk samples (13.0%) were contaminated with A. caviae, and in eight of these samples, populations of 2.0 × 102 to 3.0 × 103 CFU/ml were counted in SAA. Five cow's milk samples (3.6%) were contaminated with A. sobria, and in two of these samples, populations of 2.5 × 103 and 5.0 × 103 CFU/ml were counted in SAA. Eleven cow's milk samples (7.9%) were contaminated with other Aeromonas spp. not classified. Eight (14.0%) of the 57 ewe's milk samples analyzed were contaminated with A. hydrophila. In these samples, populations of 5.0 × 102 to 5.0 × 103 CFU/ml were counted in SAA. Six ewe's milk samples (10.5%) were contaminated with A. caviae, and populations of 1.5 × 102 to 1.0 × 103 CFU/ml were counted in SAA. Two ewe's milk samples (3.5%) were contaminated with A. sobria, and populations counted in SAA were 5.0 × 102 and 1.0 × 103 CFU/ml. Four samples (7.0%) were contaminated with other Aeromonas spp. not classified. A. hydrophila was recovered in 4 (10.2%) and 3 (8.3%) of the Anthotyros and Manouri cheese samples analyzed, respectively, but no countable populations were noted in SAA. None of the pasteurized milk, Feta cheese, and rice pudding samples yielded Aeromonas spp. The results of this work indicate that motile Aeromonas are common in raw milk in Greece. Also, the presence of A. hydrophila in the whey cheeses Anthotyros and Manouri indicates that postprocessing contaminations of these products with motile Aeromonas may occur during production.

scholarly journals Indirect and Direct Determination of the Casein Content of Milk by Kjeldahl Nitrogen Analysis: Collaborative Study

1998 ◽  
Vol 81 (4) ◽  
pp. 763-774 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Standard Deviation ◽  
Nitrogen Content ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Direct Determination ◽  
Raw Milk ◽  
Method Performance ◽  
Relative Standard ◽  
Milk Casein

Abstract The classic method for determination of milk casein is based on precipitation of casein at pH 4.6. Precipitated milk casein is removed by filtration and the nitrogen content of either the precipitate (direct casein method) or filtrate (noncasein nitrogen; NCN) is determined by Kjeldahl analysis. For the indirect casein method, milk total nitrogen (TN; Method 991.20) is also determined and casein is calculated as TN minus NCN. Ten laboratories tested 9 pairs of blind duplicate raw milk materials with a casein range of 2.42- 3.05℅ by both the direct and indirect casein methods. Statistical performance expressed in protein equivalents (nitrogen ⨯ 6.38) with invalid and outlier data removed was as follows: NCN method (wt%), mean = 0.762, sr = 0.010, SR = 0.016, repeatability relative standard deviation (RSDr) = 1.287℅, reproducibility relative standard deviation (RSDR) = 2.146%; indirect casein method (wt℅), mean = 2.585, repeatability = 0.015, reproducibility = 0.022, RSDr = 0.560℅, RSDR = 0.841; direct casein method (wt℅), mean = 2.575, sr = 0.015, sR = 0.025, RSDr = 0.597℅, RSDR = 0.988℅. Method performance was acceptable and comparable to similar Kjeldahl methods for determining nitrogen content of milk (Methods 991.20, 991.21,991.22, 991.23). The direct casein, indirect casein, and noncasein nitrogen methods have been adopted by AOAC INTERNATIONAL.

Behaviour ofStreptococcus lactisin heat treated (80 °C for 30 min) or sterilized cow's and ewe's milk

1983 ◽  
Vol 50 (3) ◽  
pp. 357-363 ◽  
Author(s):  
Francisco J. Chavarri ◽  
Jose A. Nuñez ◽  
Manuel Nuñez
Keyword(s):  
Acid Production ◽  
Generation Time ◽  
Buffer Capacity ◽  
Cow’S Milk ◽  
Cow's Milk ◽  
Vitamin Content ◽  
Streptococcus Lactis ◽  
Generation Times ◽  
Heat Treated ◽  
Ewe's Milk

SummaryGeneration times and acid production after 6 and 24 h by 20 strains ofStreptococcus lactisof dairy origin were determined in heat treated (80 °C for 30 min) and sterilized cow's and ewe's milk. Ewe's milk enhanced growth of the streptococci, with significantly (P< 0·001) shorter generation times and higher acid production after 6 h incubation than cow's milk, probably due to its higher vitamin content. The stronger buffer capacity of ewe's milk allowed a higher (P< 0·001) acid production after 24 h than cow's milk. A stimulatory effect of sterilization on generation time and acid production after 24 h was observed in cow's milk. However, the heat treated ewe's milk was shown to be a better substrate than sterilized ewe's milk forStr. lactis.

The composition of milk. Part II: Variation in the percentage of mineral constituents in cow’s milk, and their relationship with the solids not fat and protein content

1927 ◽  
Vol 17 (1) ◽  
pp. 72-93 ◽  
Author(s):  
H. T. Cranfield ◽  
D. G. Griffiths ◽  
E. R. Ling
Keyword(s):  
Standard Deviation ◽  
Phosphoric Acid ◽  
Protein Content ◽  
Ash Content ◽  
Probable Error ◽  
Cow’S Milk ◽  
Frequency Distributions ◽  
Cow's Milk ◽  
Mineral Constituents

1. 670 samples of the mixed milk from 15 herds were analysed, and the average percentages of total ash, soluble ash, insoluble ash, lime and phosphoric acid are given.2. Tables showing frequency distributions are also given, with the standard deviation, mean and probable error of mean for each constituent determined.3. Various correlations of these constituents with solids not fat and protein have been prepared, and these correlations are illustrated by graphs.It is observed that the total ash falls with the solids not fat until low values of solids not fat are reached, when the ash content appears to rise. This variation is confirmed by a curve illustrating the variation in ash content of samples of individual cow’s milk. Soluble ash rises as the solids not fat falls, but the insoluble ash shows a reverse variation. Lime and phosphoric acid both fall with the solids not fat.

scholarly journals Evaluation of the Physicochemical Quality of Raw Bovine and Goat Milk Marketed in the Steppic Region of Djelfa (Algeria)

2019 ◽  
Vol 76 (1) ◽  
pp. 55
Author(s):  
Mourad HAMIROUNE ◽  
Sounia DAHMANI ◽  
Zineb KASMI ◽  
Abdelhamid FOUGHALIA ◽  
Mahmoud DJEMAL
Keyword(s):  
Freezing Point ◽  
Bovine Milk ◽  
Goat Milk ◽  
Raw Milk ◽  
Cow’S Milk ◽  
Physicochemical Quality ◽  
Cow's Milk ◽  
Goat’S Milk ◽  
Disciplinary Procedures ◽  
Goat's Milk

This research was conducted to study the key physicochemical parameters of samples of raw bovine and goat milk collected in the steppic region of Djelfa. One hundred and six samples of raw milk were collected from April 2018 to May 2018, at points of sale and analyzed. The results showed that cow’s milk had 3.66±0.89% fat, 11.4±1.56% solid not fat, 4.35±0.61% protein, 6.35±0.89% lactose and a density of 1.0360±0.0056 with a freezing point of -0.380±0.053 °C. While goat’s milk had 3.43±0.65% fat, 10.2±0.92% solid not fat, 3.88±0.36% protein, 5.66±0.52% lactose and a density of 1.0317±0.0035 with a freezing point of -0.348±0.044 °C. This proves that cow’s milk has a slightly higher physicochemical quality than goat’s milk. In addition, the present study showed that 100% raw goat milk is wet against 97.1% raw bovine milk. This indicates the presence of cases of fraud requiring disciplinary procedures. Moreover, in the majority of the cases, the storage temperatures of the milk far exceed the values recommended by the Algerian standards (+6°C). It is necessary to establish a program of control and popularization of all the actors of the sector in order to improve the quality and the quantity of raw milk produced.

scholarly journals The influence of different kind of milk on quality of Sjenica cheese and Sjenica type cheeses made by autohthonous technology

2004 ◽  
Vol 20 (1-2) ◽  
pp. 109-118 ◽  
Author(s):  
Ognjen Macej ◽  
Snezana Jovanovic ◽  
Miroljub Barac
Keyword(s):  
Geographic Origin ◽  
Cow Milk ◽  
Cow’S Milk ◽  
Coagulation Time ◽  
Cow's Milk ◽  
Whole Milk ◽  
Technology Process ◽  
Ewe's Milk ◽  
Cheese Production

In this paper, influence of the composition of autohtonous Sjenica cheese and composition of cheese made from cow milk in the type of Sjenica cheese were comparatively investigated. Autohtonous Sjenica cheese, made from ewe's milk and Sjenica type cheese made from cow's milk both had high content of moisture (53.46% and 59.56% respectively), which is the result of production process (coagulation time, curd processing, drying and salting). According to moisture content in fat free basis - MFFB (73.51% and 73.38% respectively) both cheeses belong to soft cheeses group, and according to fat in total solids - FTS (58.66% and 46.75% respectively) they belong to a group of whole milk cheeses. Ripening coefficient of Sjenica cheese made from ewe's milk (21.42%) was larger than ripening coefficient of Sjenica type cheese made from cow's milk (20.41%). Big differences in chemical composition of both cheeses are due to non-uniformly technology, which imposes need to assimilate technology process of Sjenica cheese production and fulfill geographic origin protection of Sjenica cheese as autohthonous cheese characteristic for wider area of Sjenicko-pesterska plateau.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

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