Microbiologia
Páginas: 3 (643 palabras)
Publicado: 1 de marzo de 2013
MICROBIOLOGICAL ANALYSES OF MICOCIN II TREATED MEAT PRODUCTS
Total Plate counts:
TPC should be performed according to standard protocol for the specific meat product.
Surface counts:
1.Prepare plate count agar (PCA) and dispense in appropriate quantities. Sterilize.
2. Prepare sterile 0.1% peptone water diluent.
3. Clean surface of working area with a suitable disinfectant.
4.Clearly label the duplicate Petri plates.
5. Aseptically open the 500 gram product package.
6. Empty the contents of the package into a pre-sterilized Nalgene plastic bottle or sample bag.
7.Transfer 500 ml of sterile 0.1% peptone water diluent to the empty package to rinse out the contents of the package.
8. Transfer the 500 ml of diluent to the pre-sterilized Nalgene plastic bottle orsample bag.
9. Prepare succeeding decimal dilutions as required, using a separate sterile pipette for making each transfer. For Week 1 prepare decimal dilutions from 10-1 to 10-5.
10. Shake alldilutions immediately prior to making transfers to ensure uniform distribution of the microorganisms present.
11. Agitate each dilution bottle to re-suspend material that may have settled out duringpreparation.
12. Pipette 1 mL of the required dilutions to appropriately marked duplicate Petri plates.
13. Pour 12-15 mL of tempered Plate Count Agar into each plate, and mix by rotating andtilting. Allow to solidify. Plates should be poured not more than 15 min after preparation of dilutions.
14. Incubate plates in the inverted position for 48 h ± 4 h. Incubate at 25oC
15. Countcolonies promptly after the incubation period.
16. If possible, select plates with 20-200 colonies (including pinpoint colonies). If counts do not fall within this range select plates that fall nearest tothe 20-200 range.
17. If plates contain colonies which spread, select a representative portion of the plates free from spreaders, if possible, and count the colonies in this area. The total count...
Total Plate counts:
TPC should be performed according to standard protocol for the specific meat product.
Surface counts:
1.Prepare plate count agar (PCA) and dispense in appropriate quantities. Sterilize.
2. Prepare sterile 0.1% peptone water diluent.
3. Clean surface of working area with a suitable disinfectant.
4.Clearly label the duplicate Petri plates.
5. Aseptically open the 500 gram product package.
6. Empty the contents of the package into a pre-sterilized Nalgene plastic bottle or sample bag.
7.Transfer 500 ml of sterile 0.1% peptone water diluent to the empty package to rinse out the contents of the package.
8. Transfer the 500 ml of diluent to the pre-sterilized Nalgene plastic bottle orsample bag.
9. Prepare succeeding decimal dilutions as required, using a separate sterile pipette for making each transfer. For Week 1 prepare decimal dilutions from 10-1 to 10-5.
10. Shake alldilutions immediately prior to making transfers to ensure uniform distribution of the microorganisms present.
11. Agitate each dilution bottle to re-suspend material that may have settled out duringpreparation.
12. Pipette 1 mL of the required dilutions to appropriately marked duplicate Petri plates.
13. Pour 12-15 mL of tempered Plate Count Agar into each plate, and mix by rotating andtilting. Allow to solidify. Plates should be poured not more than 15 min after preparation of dilutions.
14. Incubate plates in the inverted position for 48 h ± 4 h. Incubate at 25oC
15. Countcolonies promptly after the incubation period.
16. If possible, select plates with 20-200 colonies (including pinpoint colonies). If counts do not fall within this range select plates that fall nearest tothe 20-200 range.
17. If plates contain colonies which spread, select a representative portion of the plates free from spreaders, if possible, and count the colonies in this area. The total count...
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