Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. इंटरनेट मानक “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda “Invent a New India Using Knowledge” “प0रा1 को छोड न’ 5 तरफ” Jawaharlal Nehru “Step Out From the Old to the New” “जान1 का अ+धकार, जी1 का अ+धकार” Mazdoor Kisan Shakti Sangathan “The Right to Information, The Right to Live” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता ह ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” IS 16038 (2012): Green Coffee - Determination of Proportion of Insect-Damaged Beans [FAD 6: Stimulant Foods]
Transcript
Disclosure to Promote the Right To Information
Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.
इंटरनेट मानक
“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda
“Invent a New India Using Knowledge”
“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru
“Step Out From the Old to the New”
“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan
“The Right to Information, The Right to Live”
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”
“Invent a New India Using Knowledge”
है”ह”ह
IS 16038 (2012): Green Coffee - Determination of Proportionof Insect-Damaged Beans [FAD 6: Stimulant Foods]
B U R E A U O F I N D I A N S T A N D A R D SMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
Hkkjrh; ekud
gjh dkWiQh — dhV-{kfrxzLr chal dk vuqikr Kkr djuk
Indian StandardGREEN COFFEE — DETERMINATION OF
PROPORTION OF INSECT-DAMAGED BEANS
ICS 67.140.10
IS 16038 : 2012ISO 6667 : 1985
Stimulant Foods Sectional Committee, FAD 6
NATIONAL FOREWORD
This Indian Standard which is identical with ISO 6667 : 1985 ‘Green coffee — Determination ofproportion of insect-damaged beans’ issued by the International Organization for Standardization(ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Stimulant FoodsSectional Committee and approval of the Food and Agriculture Division Council.
The text of ISO Standard has been approved as suitable for publication as an Indian Standard withoutdeviations. Certain conventions are, however, not identical to those used in Indian Standards. Attentionis particularly drawn to the following:
a) Wherever the words ‘International Standard’ appear referring to this standard, they should beread as ‘Indian Standard’.
b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practiceis to use a point (.) as the decimal marker.
In this adopted standard, reference appears to certain International Standards for which IndianStandards also exist. The corresponding Indian Standards which are to be substituted in their respectiveplaces are listed below along with their degree of equivalence for the editions indicated:
International Standard Corresponding Indian Standard Degree of Equivalence
ISO 3509 : 2005 Coffee and coffeeproducts — VocabularyISO 4072 : 1982 Green coffee in bags— Sampling
IS 7236 : 1974 Glossary of terms forcoffee and its productsIS 10814 : 1984 Method of samplinggreen coffee in bags
Technically Equivalent
do
In reporting the result of a test or analysis made in accordance with this standard, if the final value,observed or calculated is to be rounded off, it shall be done in accordance with IS 2 : 1960 ‘Rules forrounding off numerical values (revised)’.
INTERNATIONAL STANDARD IS0 6667-1985 (E)
Green coffee - Determination of proportion of insect-damaged beans
0 Introduction
The method described in this International Standard is based on experience gained in the inspection of green coffee beans and in the investigation of the most frequent types of damage to the beans and of the insect species responsible for this damage.
Visual examination of the external surface of green coffee beans is the only practical way to identify and separate beans which have been attacked by insects; thus, the method described applies only to external damage caused by insects.
1 Scope and field of application
This International Standard describes the types of damage caused by insects to green coffee beans and specifies a method for the determination of the proportion of insect-damaged beans in a lot of green coffee, together with the statistical use of the result obtained for technical, commercial and arbitration purposes.
The method is applicable to green coffee as defined in IS0 3599.
From the proportion of insect-damaged beans thus determined
- estimation of the confidence limits of the true propor- tion of insect-damaged beans for a given probability
- estimation of the probability that the true proportion of insect-damaged beans will not exceed a given value.
5 Apparatus
5.1 Magnifying glass (recommended)
A magnification of X 5 is suitable for inspection of the surface of beans.
5.2 Sample-holder (optional)
The use of a sample holder having a given number of cavities, each capable of holding a whole coffee bean, facilitates counting and separation of beans.
6 Sampling
See IS0 4072. 2 References
IS0 3509, Coffee and its products - Vocabulary.
IS0 4072, Green coffee in bags - Sampling.
3 Definition
For the purpose of this International Standard, the following definition applies.
insect-damaged bean: A coffee bean damaged externally by insects.
4 Principle
Visual examination of the external surface of green coffee beans to identity those which have been damaged by insects
Determination of the observed proportion, as a percentage, of insect-damaged beans and, if possible, identification of the species of insect responsible for the damage.
7 Damage caused by insects
NOTE - Photographs are useful as a means of illustrating damage caused by insects and other types of damage visible on the external surface of the bean. Some photographic illustrations are given in annex A.
7. I Description
A green coffee bean may show a great variety of damage caused by insects, from minor scars on the surface to a con- siderable number of holes and tunnels. It is usually impossible to distinguish minor damage from damage of mechanical origin and minor breakage.
For the purpose of this International Standard, only major damage is considered, i.e. those beans with clearly visible holes which are characteristic of insect damage and which cannot be mistaken for other damage.
If a bean shows several signs of damage, it is considered as a single damaged bean.
Indian StandardGREEN COFFEE — DETERMINATION OF
PROPORTION OF INSECT-DAMAGED BEANS
IS 16038 : 2012ISO 6667 : 1985
1
IS0 66674985 (El
8.3 Determination The two insect species which are most frequently responsible for damaged and infested beans are Hypothenemus (Stephanoderes) hampei (coffee bean borer) and Araecerus fascicula tus ( coffee bean weevil 1.
Operating under good lighting conditions, and preferably using the magnifying glass (5.1), examine the entire surface of each bean in the test portion for the different types of holes characterizing insect damage. The damage caused by these insects to the external surface of
beans is very specific and usually also indicates internal damage. In order to distinguish between a stain or surface defect and a
cavity caused by insects, check with a pin to ascertain whether there is really a hole; such a test is particularly useful along the groove of the bean. Count only those beans which show significant penetration as insect-damaged beans.
7.2 Identification of insects causing the damage
In addition to assessment of the damage, it is sometimes poss- ible, and useful, to identity the species of insect causing the damage. Damage caused by H. hampei and A. fasciculatus is different in appearance and the type of damage can thus be used to identify the insect responsible.
Separate and count the beans which show damage such as that described in 7.21 and 7.22.
9 Expression of results
7.21 Damage caused by H. hampei The observed proportion of as a percentage, is equal to
insect damaged beans, expressed
The damage seen on the bean surface is exit holes, as well as internal cavities.
usually from entry and
; x loo The holes are small (approximately neatly cut and circular..
0,3 to I,5 mm in diameter),
where There area.
is often a blue-green stain a round the damaged surface n is the number of insect-damaged beans;
N is the number of beans examined. H. hampei storage.
only infests coffee beans in the field and not in
10 Statistical interpretation of results
7.2.2 Damage caused by A. fascicufatus 10.1 Estimation damaged beans
of true proportion of insect- The visible damage on the bean surface is usually a bored hole, larger than that of H. hampei (from 1,O to 3,0 mm in diameter) and not as neatly cut. 10.1.1 General
A. fasciculatus can feed on green coffee beans during storage, if conditions are favourable, producing cavities and other exter- nal damage. .
The estimate of the true proportion of insect-damaged beans in the lot is obtained from the observed proportion of insect- damaged beans calculated as described in clause 9. The reliability of the estimate (calculation of confidence limits), for a 90 % probability, is determined by means of figure 1, from the observed proportion of insect-damaged beans and the number of beans examined.
8 Procedure
81 , Preparation of the test sample 10.1.2 Use of figure 1
Carefully mix the laboratory sample (see homogeneity of laboratory samples).
annex B for a test for Find on the abscissa the observed of insect-damaged beans.
proportion , as a percen tage,
From this point, draw a vertical line which bisects both curves corresponding to the number of beans examined (interpolate for test portions comprising a number of beans not shown in figure 1).
8.2 Test portion
Take at random at least 100 whole green coffee beans from the test sample. During counting, replace every broken bean selected by a whole bean taken at random from the test sample. The ordinates at these points of intersection (a for the lower
curve and b for the upper curve) indicate the confidence limits corresponding to the observed proportion of insect-damaged beans. NOTE - Broken beans will cause errors because a damaged bean may
be counted twice or pieces of beans may be counted as whole beans in the total. For this reason, in order to avoid any confusion in the results, the broken beans should be eliminated after being counted and it can be assumed that the proportion of insect-damaged beans subsequently determined on whole beans represents the proportion of insect- damaged beans within the laboratory sample.
It can be stated, with a 90 % probability, that the true propor- tion of insect-damaged beans within the lot is between a and b. [i.e. Pr (a < p < b) = 0,90, wherep is the true proportion of insect-damaged beans. 1
2 2
IS 16038 : 2012ISO 6667 : 1985
10.1.3 Example From this point, draw a vertical line until it intersects the curve corresponding to the observed proportion, as a percentage, of insect-damaged beans (interpolate between the curves for frac- tional values).
Data :
Number of beans examined: 400
Observed proportion of insect-damaged beans: 10 % The ordinate corresponding to the point of intersection gives the probability (confidence level) that the true proportion of insect-damaged beans within the lot is lower than a predeter- mined value, the observed proportion of insect-damaged beans being known.
From figure 1:
a = 7,5 %
b = 12,5 %
Thus :
Pr (7,5 % < p < 12,5 %I = 030 10.2.3 Interpretation of results
If the probability obtained is equal to or greater than the critical probability established by specifications, agreements, etc., the lot shall be considered as containing less insect-damaged beans than the critical level.
i.e. with a probability of 90 %, the proportion of insect- damaged beans within the lot is between 7,5 and 12,5 %.
10.1 A Reducing the two-sided confidence interval
If the probability obtained proceed as follows.
is less than the critical probability, If it is wished to teed as follows.
reduce the two-sided confidence interval, pro-
Take a second test portion of at least 200 beans and proceed as described in 8.3 (if the second test portion appears to be dif- ferent from the first, check the homogeneity of the laboratory sample by the method described in annex B).
Take a second test portion of at least 200 beans and repeat the operations specified in 8.3 (if the second portion appears to be different from the first, check the homogeneity of the laboratory sample by the method specified in annex B).
Add together the numbers of insect-damaged beans from the first and second test portions and the numbers of beans ex- amined in both test portions.
Add together the numbers of damaged beans from the first and second test portions and the numbers of beans examined in both test portions.
Calculate the new proportion of insect-damaged beans and proceed as indicated in 10.1.2 to determine the new confidence limits.
Calculate the new observed proportion beans and proceed as specified in 10.2.2.
of insect-damaged
10.2.4 Examples
10.2 Determination of the probability that the true proportion of insect-damaged beans does not exceed a given value
Data : Example 1 Example 2
Number of beans examined 400 350 Observed proportion of 9% 5% insect-damaged beans Selected value 10 % 7,5 % From : (refer to (refer to
figure 4) figure 5) Probability 73 % 97 %
10.2.1 General
The probability that the true proportion of insect-damaged beans in a lot does not exceed a given value is obtained from the observed proportion of insect-damaged beans in the test portion (see clause 9 and figures 2 to 6).
Figures 2 to 6, which are based on the assumption that the distribution is fundamentally binomial, indicate the probability that the true proportion of insect-damaged beans in a lot does not exceed a predetermined value, once the proportion of insect-damaged beans in a sample of n beans is established.
Thus :
a) in the case of example 1, there is a 73 % probability that the true proportion of insect-damaged beans in the lot is less than 10 %;
b) in the case of example 2, there is a 97 % probability that the true proportion of insect-damaged beans is less than 7,5 %.
When testing a lot of coffee, a critical probability (confidence level) should be selected to become one of the factors in the decision process. A probability of 90 % is suggested as being appropriate for the use of this method. However, since the method is a general one, other probabilities may be chosen. 11 Test report
The test report shall show the method used and the results ob- tained. It shall also mention any operating details not specified in this international Standard, or regarded as optional, together with details of any incidents likely to have influenced the resurts.
10.2.2 Use of figures 2 to 6
Select the figure corresponding to the which should not be exceeded.
predetermined value
Find on the abscissa the number of beans examined. If more than one test portion was examined, take the number of beans examined as the sum for all the test portions.
The test report shall conta the complete identifi cation
i n all the information of the sample.
necessary for
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IS 16038 : 2012ISO 6667 : 1985
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IS 16038 : 2012ISO 6667 : 1985
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Annex A
Illustrations of damaged beans
A.1 Beans damaged by H. hampei
A.2 Beans damaged by A. fascicu/at/s
,..::.. : _: .,::.
..i. . .
10
IS 16038 : 2012ISO 6667 : 1985
ns damaged by causes other than insects
IS 16038 : 2012ISO 6667 : 1985
5
IS 16038 : 2012ISO 6667 : 1985
1
IS 16038 : 2012ISO 6667 : 1985
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Annex B
Test for homogeneity of the laboratory sample
The following statistical test can be used to determine whether the hypothesis of laboratory sample homogeneity should be re- jected. The test should be applied whenever there is a “suspiciously” large difference between the observed propor- tions of insect-damaged beans in the first and second test por- tions.
Let
5, be the observed proportion, as a percentage, of insect- damaged beans in test portion 1, divided by 100;
& be the observed proportion, as a percentage, of insect- damaged beans in test portion 2, divided by 100;
fi be the sum of the numbers of insect-damaged beans in test portions 1 and 2, divided by the total number of beans examined for test portions 1 and 2;
*1 be the number of beans examined in test portion 1;
n2 be the number of beans examined in test portion 2.
Then
Z= 5, - &
J$ (1 -j) Wnl + l/*2)
For a 90 % significance test, if/Z1 > 1,645, the labora sample should be considered to be inhomogeneous.
tory
For a 95 % significance test, if /ZI > 1,96, the laboratory sample should be considered to be inhomogeneous.
If the hypothesis of laboratory sample homogeneity is rejected, a new laboratory sample should be taken from the bulk sample.
12
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IS 16038 : 2012ISO 6667 : 1985
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Review of Indian Standards
Amendments are issued to standards as the need arises on the basis of comments. Standards are alsoreviewed periodically; a standard along with amendments is reaffirmed when such review indicates thatno changes are needed; if the review indicates that changes are needed, it is taken up for revision. Usersof Indian Standards should ascertain that they are in possession of the latest amendments or edition byreferring to the latest issue of ‘BIS Catalogue’ and ‘Standards: Monthly Additions’.
This Indian Standard has been developed from Doc No.: FAD 6 (2020).
Amendments Issued Since Publication______________________________________________________________________________________
Amendment No. Date of Issue Text Affected______________________________________________________________________________________
