News: Adulteration widespread in olive oil

Producers claim the sale of adulterated or fake products is even more prevalent in Turkey’s olive oil market than in the honey market, in which the problem has attracted attention recently, the Doğan news agency reported yesterday.

“The problem of fake products in the olive oil market is five times bigger than that in the honey market,” Doğan news agency quoted producers as saying. The National Olive and Olive Oil Council has reported 117 complaints to the Food, Agriculture and Livestock Ministry so far.

A board under the Ministry of Customs and Trade recently found that some honey firms were selling non-honey substitute substances as honey. The Turkish Board of Advertising has imposed heavy fines on two honey companies for taking advantage of consumers by using deceptive statements in their commercials.

Such scandals regarding food security have begun to break out since the ministry recently began exposing the names of companies that have been found to sell or produce fake products.

Commenting on the fact that only two firms have been exposed for selling fake honey, Metin Ölken, the head of the Olive Friends Association, said the process of exposing a food company’s wrongdoing is slow. Still, it would be helpful to apply the same process in the olive oil market, he said, adding that “exposing the names of the companies is still not a definite solution. They resurface under different names after laughing all the way to the bank.”

Ölken said large olive oil companies have an interest in allowing the production of fake or adulterated oil to continue. “In fact, they do not want this problem to be solved, because the consumers do not buy olive oil from smaller companies for fear of purchasing fake olive oil.”

Source: http://www.hurriyetdailynews.com/adulteration-widespread-in-olive-oil.aspx?pageID=238&nID=17527&NewsCatID=345

Detection of Honey Adulterations

Bees are sometimes fed with cane sugar. Often glucose syrup is poured over honeycomb from which the honey has been extracted, and the mixture sold as genuine honey. Gelatin may be added to increase the weight or to thicken the more voluble adulterants. The ash of genuine honey is not over 0.3 per cent. Whenever the ash is greater than this it should be tested for calcium sulfate, the presence of a considerable quantity of which is an almost certain proof that starch glucose or invert sugar has been added to the honey. Sulfates may be detected by adding barium chloride to the aqueous solution of the honey and precipitating barium sulfate. If the ash is high and considerable chlorides are present, molasses has quite probably been added to the honey. The presence of chlorides may be determined by the addition of silver nitrate which precipitates silver chloride.

Molasses (sugar and water): A cotton wick dipped in pure honey, when lighted with a match stick, burns. If adulterated, the presence of water will not allow the honey to burn. If it does, it will produce a crackling sound.

Commercial invert sugar (mixture of glucose and fructose) : Fiche’s Test: Mix about 5 gr.of the honey with 10 ml of ether in a mortar, using a pestle. Decant off the ether extract into a chin apish. Repeat twice with more ether and collect all the extract in the same dish. Allow the ether to evaporate off at room temperature. To the remaining residues in the dish, add a large drop of a 1% solution of freshly sublimed resorcinol in concentrated hydrochloric acid. Immediate appearance of a cherry red color indicates commercial sugar.

Cane Sugar: The presence of cane sugar can be detected with certainty only by the use of the polarimeter. Its presence in large quantity gives a high right-handed rotation.

Gelatin: Dilute a portion of the sample and add a solution of tannic acid. A precipitate indicates the presence of gelatin. Treat the sample with alcohol, and gelatin, if present, will be left undissolved, and it will give its characteristic odor on ignition.

Maple Syrup: This is sometimes adulterated with glucose, molasses, golden syrup, and with ordinary white sugar. There are no satisfactory simple chemical tests for these substances. Pure maple syrup should have an ash not lower than 0.35 to 0.40 per cent. A lower ash shows that cane sugar has been added. A higher ash would indicate the presence of molasses or brown sugar stock. These last two adulterants, if present in great abundance, may be detected by taste.

Glucose : This may be detected by the use of the polarimeter. Pure maple s)n*up gives 53.1 to 60 direct, and — 22.2 to — 21.9 after hydrolysis. Maple syrup adulterated with glucose gives 80 to 100 direct and 18.9 to 45.6 after hydrolysis (according to Ogdon).

Detection of Butter and Ghee Adulterations (Basic methods)

Butter is adulteration with Mutton, fat, beet, fat and different oils, potato pulp starch, Jaggery, soft paraffin’s, vegetable oil, hydrogenated fat and margin.

Coal tar dye : Melt the butter in a test tube kept in a hot water bath and continue heating until the fat and water layers completely separate out. Decant off the butter fat from the top into a clean dry test tube. In another test tube, dissolve about 2 mt of' clear fat in ether, add to it 1 to 2 ml of 50% hydrochloric acid, shake and allow to settle. Formation of a pink to wine red colour in the lower acid layer shows coal tar dye.

Vanaspati : Dissolve a pinch of cane sugar in 10 ml concentrated hydrochloric acid taken in a glass stoppered test tube. Add 10 ml of the melted ghee, stopper the bottle and shake vigorously for two minutes. Let it stand till 2 layers separate. If the lower layer turns pink or red, the ghee contains vanaspati.

Mashed potatoes, sweet potato and other starches: The presence of mashed potatoes and sweet potatoes in a sample of butter can easily be detected by adding a drop of tincture of iodine. Iodine which is brownish in color turns to blue if mashed potatoes / sweet potatoes / other starches are present.

Coloring Matter: Martinis Test. — Add 2 parts of carbon bisulfide, a little at a time and with frequent shaking, to 15 parts of alcohol. Shake 25 cc. of this solution with 5 grams of the butter, and let stand for some time. The carbon bisulfide dissolves out the fatty matter and settles to the bottom. The alcohol remains on top and will dissolve out any artificial colors that may be present. If only a little coloring matter is present use more of the butter.

Annatto: Evaporate a portion of the extract to dryness and add sulfuric acid to the residue. If annatto is present a greenish blue color forms. Should a pink tint result the presence of a coal-tar color is to be suspected.

Saffron: When saffron is present, nitric acid colors the alcoholic extract green, and hydrochloric acid colors it red.

Turmeric: Add ammonia to the alcoholic extract, and if it turns brown it indicates the presence of turmeric.

Marigold : Add silver nitrate to the extract, and if it turns black the presence of marigold is indicated.

Detection of Milk Adulterations (Basic methods)

Milk adulteration may be defined as any change caused in the natural level of milk ingredients. These changes may be brought about by addition of some foreign matter to milk or by removing some more valuable ingredients e.g. fat out of it. Milk is the most frequently adulterated food product in developing countries . There are many methods known for detection of adulteration in milk but the methods discussed below are simple but rapid and sensitive methods to detect adulteration.

Possible adulterants:

- Water Reconstituted milk/Recombined milk/Dried milk Whey Mixing of milk of one species with other Cow milk in goat milk/ sheep milk Cow milk in buffalo milk Buffalo milk in Cow milk Thickening agents Starch Cane sugar Gelatin Cellulose

- Preservatives Boric acid/borates Formaldehyde Benzoic acid Salicylic acid Hydrogen peroxide Hypo chloride Neutralizers Lime water Sodium bicarbonate Sodium carbonate Sodium hydroxide

- Fertilizers/Additive Urea Glucose Ammonium sulphate Potassium nitrate Salts

- Coloring matter Annatto Coal tar dies Miscellaneous Adulterants Vegetable oil Soybean Protein Urine Coconut water Dirt QAC Antibiotics Wash water/detergents

I. Detection of Neutralizers in milk

Rosalic acid test (Soda Test)
In milk neutralizers like hydrated lime, sodium hydroxide, sodium carbonate or sodium bicarbonate are added which are generally prohibited.

How to detect?
Take 5 ml of milk in a test tube and add 5 ml alcohol followed by 4-5 drops of rosalic acid. If the colour of milk changes to pinkish red, then it is inferred that the milk is adulterated with sodium carbonate / sodium bicarbonate and hence unfit for human consumption.
This test will be effective only if the neutralizers are present in milk. If the added neutralizers are nullified by the developed acidity, then this test will be negative. In that case, the alkaline condition of the milk for the presence of soda ash has to be estimated.

How to proceed?
Take 20 ml of milk in a silica crucible and then the water is evaporated and the contents are burnt in a muffle furnace. The ash is dispersed in 10 ml distilled water and it is titrated against decinormal (N/10) hydrochloric acid using phenolphthalein as an indicator. If the titre value exceeds 1.2 ml, then it is construed that the milk is adulterated with neutralizers.

II. Test for detection of hydrogen peroxide

Take 5 ml milk in a test tube and then add 5 drops of paraphenylene diamine and shake it well. Change of the colour of milk to blue confirms that the milk is added with hydrogen peroxide.

III. Test for detection of formalin

Formalin (40%) is poisonous though it can preserve milk for a long time.

How to detect?
Take 10 ml of milk in test tube and 5 ml of conc. sulphuric acid is added on the sides of the test tube with out shaking. If a violet or blue ring appears at the intersection of the two layers, then it shows the presence of formalin.

IV. Test for detection of sugar in milk

Generally sugar is mixed in the milk to increase the solids not fat content of milk i.e. to increase the lactometer reading of milk, which was already diluted with water.

How to detect?
Take 10 ml of milk in a test tube and add 5 ml of hydrochloric acid along with 0.1 g of resorcinol. Then shake the test tube well and place the test tube in a boiling water bath for 5 min. Appearance of red colour indicates the presence of added sugar in milk.

V. Test for detection of starch

Addition of starch also increases the SNF content of milk. Apart from the starch, wheat flour, arrowroot, rice flour are also added.

How to detect?
Take 3 ml milk in a test tube and boil it thoroughly. Then milk is cooled to room temperature and added with 2 to 3 drops of 1% iodine solution. Change of colour to blue indicates that the milk is adulterated with starch.

VI. Test for detection of glucose

Usually poor quality glucose is added to milk to increase the lactometer reading. There are two tests available to detect the adulteration of milk with glucose.

How to proceed?
1. Phosphomolybdic or Barford Test

Take 3 ml of milk in a test tube and add 3 ml Barford’s reagent and mix it thoroughly. Then keep it in a boiling water bath for 3 min and then cool it for 2 min by immersing in tap water with out disturbance. Then add 1 ml of phosphomolybdic acid and shake. If blue colour is visible, then glucose is present in the milk sample.

2. Diacetic test

Take a strip of diacetic strip and dip it in the milk for 30 sec to 1 min. If the strip changes colour, then it shows that the sample of milk contains glucose. If there is no change in the colour of the strip, then glucose is absent. In this method the presence of glucose in milk can be quantified by comparing the colour developed with the chart strip.

VII. Test for detection of urea

1. Urea is generally added in the preparation of synthetic milk to raise the SNF value.
Five ml of milk is mixed well with 5 ml paradimethyl amino benzaldehyde (16%). If the solution turns yellow in colour, then the given sample of milk is added with urea.

2. Take 5 ml of milk in a test tube and add 0.2 ml of urease (20 mg / ml). Shake well at room temperature and then add 0.1 ml of bromothymol blue solution (0.5%). Appearance of blue colour after 10-15 min indicates the adulteration milk with urea.

VIII. Test for detection of ammonium sulphate

The presence of sulphate in milk increases the lactometer reading.

How to proceed?
5 ml of hot milk is taken in a test tube and added with a suitable acid for e.g. citric acid and the whey thus separated is filtered. Collect the whey in another test tube and add 0.5 ml of 5% barium chloride. Appearance of precipitate indicates the presence of ammonium sulphate in milk.

IX. Test for detection of salt

Addition of salt in milk is mainly resorted to with the aim of increasing the corrected lactometer reading.

How to detect?
Five ml of silver nitrate (0.8%) is taken in a test tube and added with 2 to 3 drops of 1% potassium dichromate and 1 ml of milk and thoroughly mixed. If the contents of the test tube turn yellow in colour, then milk contains salt in it. If it is chocolate coloured, then the milk is free from salt.

X. Test for detection of pulverized soap

Take 10 ml of milk in a test tube and dilute it with equal quantity of hot water and then add 1 – 2 drops of phenolphthalein indicator. Development of pink colour indicates that the milk is adulterated with soap.

XI. Detection of detergents in milk

Take 5 ml of milk in a test tube and add 0.1 ml of bromocresol purple solution. Appearance of violet colour indicates the presence of detergent in milk. Unadulterated milk samples show a faint violet colour.

XII. Detection of water in milk

Though the adulteration of milk with water can be checked by lactometer reading, other adulterations too affect the lactometer reading. Hence freezing point depression, recognized by AOAC, is usually adopted.
Percentage of water added = (Normal freezing point – Observed freezing point)X 100 / (Normal freezing point)
Normal freezing point of milk is taken as –0.55°C. A tolerance level of 3% is given which is equivalent to specifying a minimum freezing point depression for authentic milk of –0.55°C.

XIII. Detection of skim milk powder in milk

If the addition of nitric acid drop by drop in to the test milk sample results in the development of orange colour, it indicates the milk is adulterated with skim milk powder. Samples with out skim milk powder shows yellow colour.

XIV. Detection of vegetable fat in milk

The characteristic feature of milk is its fatty acid composition, which mainly consists of short chain fatty acids such as butyric, caproic, caprylic acid; whereas the vegetable fats consist mainly of long chain fatty acids and hence adulteration of vegetable fat in milk can be easily found out by analyzing the fatty acid profile by gas chromatography.

XV. Detection of buffalo milk in cow milk

The presence of buffalo milk in cow milk is tested by Hansa test. It is based on immunological assay. One ml of milk is diluted with 4 ml of water and then it is treated with 1 ml of antiserum. The characteristic precipitation reaction indicates the presence of buffalo milk in the sample taken. (The antiserum is developed by injecting buffalo milk proteins into rabbits).

XVI. Detection of benzoic and salicylic acid in milk

Five ml of milk is taken in a test tube and acidified with concentrated sulphuric acid. 0.5% ferric chloride solution is added drop by drop and mixed well. Development of buff colour indicates presence of benzoic acid and violet colour indicates salicylic acid.

XVII. Detection of borax and boric acid in milk

Five ml of milk is taken in a test tube to which 1 ml of concentrated hydrochloric acid is added and mixed well. Tip of a turmeric paper is dipped into the acidified milk and it is dried in a watch glass at 100°C or over a small flame. If the turmeric paper turns red, it indicates the presence of borax or boric acid.
Confirmation can be made by adding a drop of ammonia solution on the turmeric paper and if the red colour changes to green, it shows the presence of boric acid.

XVIII. Detection of limewater in milk

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XIX. Detection of Water in milk

The lactometer reading should not ordinarily be less than 1.026

XX. Detection of formaldehyde in milk

( Hechner Test) Take 10 ml of milk in a test tube. Add 0.5 ml of ferric chloride solution and mix well. Add concentrated sulphuric acid slowly from the side so that it forms separate layer at the bottom without mixing with milk.Development of violet ring at the junction of two layers indicates presence of formaldehyde. Leach Test Take 5 ml of milk in a test tube & add equal volume of Hcl containing ferric chloride. Heat over a small flame for 5 min. Break the curd by rotating the tube & observe for the colour. Violet colour in the curd indicates presence.