Food microbiology Exam questions
and answers graded A+
Relationship between organisms and shelf life - ANS✅✅the higher number of organisms the lower
the shelf life
Psychrotrops incubation temp - ANS✅✅20 degrees C
Mesophiles incubation temp - ANS✅✅35-37 degrees C
thermophiles - ANS✅✅50 degrees C
4 basic methods to determine the "total" number of microorganism - ANS✅✅1. standard plate
count (SPC)
2. most probable numbers (MPN)
3. Dye reduction Techniques
4. Direct Microscopic counts (DMC)
Steps of Standard Plate Count - ANS✅✅1. blend/homogenize food sample
2. Serial sterile dilution (10-fold)
3.plating (pour or surface)
4. incubation of isolated colonies
5.count colonies
Examples of homogenization of food samples - ANS✅✅1. waring blender
2. **Colwell Stomacher
disadvantages of pour plating method - ANS✅✅-too hot can kill cells
-hard to pick colonies for counting
-can be hard to see colonies
and answers graded A+
Relationship between organisms and shelf life - ANS✅✅the higher number of organisms the lower
the shelf life
Psychrotrops incubation temp - ANS✅✅20 degrees C
Mesophiles incubation temp - ANS✅✅35-37 degrees C
thermophiles - ANS✅✅50 degrees C
4 basic methods to determine the "total" number of microorganism - ANS✅✅1. standard plate
count (SPC)
2. most probable numbers (MPN)
3. Dye reduction Techniques
4. Direct Microscopic counts (DMC)
Steps of Standard Plate Count - ANS✅✅1. blend/homogenize food sample
2. Serial sterile dilution (10-fold)
3.plating (pour or surface)
4. incubation of isolated colonies
5.count colonies
Examples of homogenization of food samples - ANS✅✅1. waring blender
2. **Colwell Stomacher
disadvantages of pour plating method - ANS✅✅-too hot can kill cells
-hard to pick colonies for counting
-can be hard to see colonies