Post on 14-Apr-2018
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Microbiological criterion and value ofsampling
Dr. V. Sudershan Rao
National Institute of Nutrition ICMR
Hyderabad
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Microbiolo ical CriteriaMicrobiolo ical CriteriaA microbiological criterion defines the limit above which aA microbiological criterion defines the limit above which afood is considered to be contaminated at an unacceptablefood is considered to be contaminated at an unacceptableeve w t a m croeve w t a m cro--organ sm, ts tox n or meta o te an sorgan sm, ts tox n or meta o te an s
therefore considered to be unsafe for consumption.therefore considered to be unsafe for consumption.A microbiological criterion also contains the followingA microbiological criterion also contains the followingcomponen s:componen s:
the sampling plan (the number of samples of a food that the sampling plan (the number of samples of a food thats ou e ta ens ou e ta en
the laboratory method (the method which should be used the laboratory method (the method which should be usedto test the food)to test the food)
the stage in the food chain where the criterion applies the stage in the food chain where the criterion applies the corrective action to be taken when the criterion is not the corrective action to be taken when the criterion is notmet (the action to be taken when there are unsatisfactorymet (the action to be taken when there are unsatisfactoryresults).results).
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ProcessProcess hygienehygiene criteriacriteria:: TheseThese criteriacriteria indicateindicate if if thetheproductionproduction processprocess isis operatingoperating inin aa hygienichygienic mannermanner.. TheyThey areareapplicableapplicable toto foodstuffsfoodstuffs atat variousvarious stagesstages throughoutthroughout theirtheirproductionproduction processesprocesses..
FoodFood safetsafet criteriacriteria:: TheseThese criteriacriteria definedefine thethe acce tabilitacce tabilit of of aafoodfood inin termsterms ofof itsits microbiologicalmicrobiological safetysafety.. TheyThey areare applicableapplicabletoto foodfood placedplaced onon thethe marketmarket andand throughoutthroughout thethe shelfshelf--lifelife ofofthethe foodfood..
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Microbiological criterion under Indian regulations
Canned meat &meat roducts 2002Total Plate Count 1000cfu/g
E. coli 0/25g
Staph aureus 0/25gClostridum botulinum 0/25g
Clostridium perfringens 0/25g
Frozen mutton, goat, beef &buffalo meat (2002)
Total Plate Count 1,00,000cfu/g
Salmonella 0/25g
E. coli 100cfu/g
Staph aureus 100cfu/g
ostri um otu inum c u g
Clostridium perfringens 30cfu/g
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Microbiological criterion under Indian
u
Spices(2006)
Salmonella 0cfu/25gFrozen prawns, Raw (2005)
Total Plate count Not more than 5,00,000 cfu/g
E. coli ot more than 20 cfu/
Staph aureus Not more than 100 cfu/g
Shigella 0 cfu/25g
Vibro cholerae 0 cfu/25g
Vibro parahaemolyticus 0 cfu/25g
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Frozen prawns, Cooked (2005)
, ,E. coli 0 cfu/25g
Staph aureus 0 cfu/25g
Salmonella 0 cfu/25g
Shigella 0 cfu/25g
Vibro cholerae 0 cfu/25
Vibro parahaemolyticus 0 cfu/25g
,
Fruit beverages (2005)
ota p ate ount ot more t an c u mYeast and Mould count Not more than 2cfu/ml
Coliform 0/100ml
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Yoghurt/Dahi(2006)
Total Plate Count Not more than 10,00,000cfu/g
Coliform Not more than 10cfu/g
E. coli 0cfu/gSalmonella 0cfu/25g
Shigella 0cfu/25g
Yeast & mould Not more than 100cfu/g
naero c pore coun c u g
Listeria monocytogens 0cfu/g
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Components of Microbiological Criteria as per
Codex1. A statement of the organisms of concern and /or their toxins
.
3. A sampling plan, when and where sampling to be taken
4. M cro a m ts cons ere appropr ate to t e oo
5. The number of sample units that should conform to theses limits
What is sampling plan?
It is a statement of the criteria applied to a lot based on appropriate
methods. It should have a sampling procedure and decision
criteria.
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USFDA refusals on account of presence of
Salmonella
AugustAugust 77
JulyJuly 2626
JuneJune 2424MayMay 99
AprilApril 1717
MarchMarch 1515
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False negative at the time of shipping and positive
Could it be due to
- error n samp ng
- Improper laboratory methods used ?
Impact
- Food safety objective is defeated
- Economic loss to the countr
- Effect on the image of the country
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A well designed sampling plan
can define the robabilit of detectin
microorganism in lot
particular organism
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Choice of plan to should take into account
1.Risks to ublic health associated with hazard
. uscep y o e arge group o consumers
3.Heterogeneity of distribution of micro
organisms when variable plans are employed
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Decision Tree for Sampling plan
Organism of Concern
Presence or absence tests No
Yes Measure y count
-
-
No Acce t the resence of this or anism?
Yes
C= 0 C> 0
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Essential elements of sampling plan
1.The microbe or rou of microbes of concern or interest2. Number of samples tested (n)
.
4. Microbiological limit (s),
. Accepta e (< m)
. Marginally acceptable (>m andM)
5. Number of samples which fall into each category of
microbiological limits( ie acceptable /marginal/unacceptable)
plan
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Types of Sampling
Two class attributes plan
One limit
Two attributes Less than or equivalent
More than the limit
Three class attributes plan
Three attributes Less than or equivalent GMP limit
ore an u ess an azar ous m
More than hazardous limits
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Too Big: Too small:
Requires Wont do
too many
resources
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Binomial probability of detecting defective units with
defectives
Probability of detecting defective units
No of samplesNo of samples
testedtested
00 11 22
55 0.860.86 0.1330.133 0.0080.008
1010 0.740.74 0.2280.228 0.0320.032
2020 0.540.54 0.3360.336 0.0990.099
5050 0.220.22 0.3370.337 0.2560.256
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Calculation of sample number based on expected levels of
Binomial distribution: CI 95%, RP=20%
15%15% 544544
25%25% 288288
35%35% 178178
40%40% 144144
45%45% 117117
50%50% 9696
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Ref: Dahms S, Mitt.Lebensm, Hyg, 95, 32-44 (2004)
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Ref: Dahms S, Mitt.Lebensm, Hyg, 95, 32-44 (2004)
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Sampling Plan for Salmonella (USFDA)
Food Cate or I :- This includes the foods that would not normall besubjected to a process lethal to Salmonella between the time of samplingand consumption. they are intended for consumption by the aged, the infirm,and infants.
Food Category II :- This includes the foods that would not normally besubjected to a process lethal to Salmonella between the time of sampling
Food Category III :- Food that would normally be subjected to a process
lethal to salmonella between the time of sampling and consumption
Sam le size Cate or I 60 units
Category II 30 units
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Category I &II All High risk foods, nuts and nut products, oils,
coffee-tea candies and prepared salads
Cate or III Processed rains , fresh ve etables, ve etable
oils and food additives
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a mone a n ee
n=20 c=0 m=0
All the samples must be negative
If one sam le is ositive, entire lot is re ected
To make more effective sampling plan increase the
number
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Sampling Plans
Microbiological limit in foods
nn cc mm MM
APCAPC 55 33 1010 1010
S.aureusS.aureus 55 11 101022 101044
E.coliE.coli 55 22 1010 101022
SalmonellaSalmonella 1010 00 00 00
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Market samples of Poultry products in Hyderabad
FoodFood nn 101066 101044 101022
Levels ofStaphylococcus aureus contamination
ChickenChickenfried ricefried rice
9494 88 22 77
ChickenChicken
noodlesnoodles
9494 1212 33 55
eve s o a mone a con am na on
FoodFood nn 101066 101044 101022
ChickenChicken
fried ricefried rice
9494 00 00 00
ChickenChicken
noodlesnoodles
9494 11 00 00
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Plan stringency in relation to degree of health hazard and
conditions of use
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Ref: Modern Food Microbiology, Seventh edition, 2005
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Example of effective use of Microbiological
criteria and sampling design of ICMSF with
HACCP
Rutgers Food Service Program
17 years experience30 million meals
1600 food samples (1983-89)
.
No foodborne illness
Ref : James Jay . Modern Food Microbiology 2005
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Thank you for your kind attention