Methods of assessment: The presence of foreign matters on the surface can be detected by either of the following methods:
Visual inspection: In large tanks/silo proper light arrangement is made to inspect cleanliness status. Remote places could be inspected by focussing powerful light over the surface.
Touching: Touching the cleaned surface with clean & sanitized fingers shall help in knowing the presence of physical/chemical matters. Detergent residue gives whitish appearance over the fingers, whereas presence of milk fat gives oily impression.
Drop test: When clean water is dropped over the inclined/vertical surface, it gives specific flow pattern depending upon the extent of cleanliness. Excessive water-liner breaks could be observed on improperly cleaned surface.
pH test: The most of detergents are alkaline and their presence after rinsing could be detected by checking the pH of the surface. More than 7pH will indicate presence of traces of detergents.
Indicator test: The presence of detergent could also be noticed by applying phenolphthalein indicator over the cleaned/rinsed surface. The trace of detergent will change the colour of the indicator into pink.The sanitary conditions of the cleaned and sanitized surfaces are assessed by the following methods.
Rinse method: The sterilized surfaces are rinsed with distilled water. The result is presented to know the microbial load as colony per litre of rinse. From the rinse collected, a sample of known quantity is tested for counting the colony and the count is multiplied with the either factors of the rinse quantity. Rinse quantity has two factors, one is the sample quantity and other is the quotient of rinse quantity and sample quantity.
Norms for assessing the effectiveness:
Touching: Touching the cleaned surface with clean & sanitized fingers shall help in knowing the presence of physical/chemical matters. Detergent residue gives whitish appearance over the fingers, whereas presence of milk fat gives oily impression.
Drop test: When clean water is dropped over the inclined/vertical surface, it gives specific flow pattern depending upon the extent of cleanliness. Excessive water-liner breaks could be observed on improperly cleaned surface.
pH test: The most of detergents are alkaline and their presence after rinsing could be detected by checking the pH of the surface. More than 7pH will indicate presence of traces of detergents.
Indicator test: The presence of detergent could also be noticed by applying phenolphthalein indicator over the cleaned/rinsed surface. The trace of detergent will change the colour of the indicator into pink.The sanitary conditions of the cleaned and sanitized surfaces are assessed by the following methods.
Rinse method: The sterilized surfaces are rinsed with distilled water. The result is presented to know the microbial load as colony per litre of rinse. From the rinse collected, a sample of known quantity is tested for counting the colony and the count is multiplied with the either factors of the rinse quantity. Rinse quantity has two factors, one is the sample quantity and other is the quotient of rinse quantity and sample quantity.
Norms for assessing the effectiveness:
Swab method: The sanitized surface is wiped with a clean and sanitized cotton and rinsed with the distilled water of known volume. A representative area is properly wiped and rinse is prepared, which is tested for determining microbial load in terms of colonies present in the sample. Actual quantity present in the known rinse will be calculated to find out colony per 900 sq.cm area.
Norms for assessing the effectiveness:
Always neutralize the effect of chlorine in the sample of rinse water by adding 0.05% of sodium thiosulphate to avoid any lethal effects on the viable microorganism.When quaternary ammonium compounds are used as sanitizing chemicals may be neutralized by adding 0.4% lecithin and 1% Tween 20.
Adinosine-triphosphate (ATP) tests provide an indication of viable micro-organism within few seconds and assess the effectiveness of sanitization. This test is useful in correcting the cleaning/sanitizing process well before the commencement of production.
Norms for assessing the effectiveness:
Always neutralize the effect of chlorine in the sample of rinse water by adding 0.05% of sodium thiosulphate to avoid any lethal effects on the viable microorganism.When quaternary ammonium compounds are used as sanitizing chemicals may be neutralized by adding 0.4% lecithin and 1% Tween 20.
Adinosine-triphosphate (ATP) tests provide an indication of viable micro-organism within few seconds and assess the effectiveness of sanitization. This test is useful in correcting the cleaning/sanitizing process well before the commencement of production.
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