PP 1

Question 1

The following storage temperature is recommended for samples of technological swabs awaiting microbiological testing:

Answer 1

1-4*C

Question 2

The name of culture medium designed to separate microorganisms from a solid test product into a liquid phase and/or to reduce their concentration without any multiplication or inhibition during the time of contact is:

Answer 2

Suspension medium

Question 3

To detect the presence of abscence of Salmonella, the initial suspension is prepared by mixing:

Answer 3

25 grams of the test portion with 225 mL of buffered peptone water

Question 4

The enumeration of Enterobacteriaceae using the most probable number (MPN) is applicable when the expected number of Enterobacteriaceae is:

Answer 4

Below 10 CFU/mL of the test sample

Question 5

To determine the total count of psychrotrophs, the inoculated PCA plates are incubated:

Answer 5

At 5*C for 10 days

Question 6

The following apparatus is used to prepare further decimal dilutions from the initial suspension:

Answer 6

Vortex mixer

Question 7

In the microbiological laboratory, sterilization of glassware and materials prior to use is preferably done by:

Answer 7

Dry heat in a sterilizing oven at 170*C for at least 1 hour

Question 8

The culture medium TBX contains the following selective agent:

Answer 8

X-glucuronide

Question 9

When enumeration of beta-glucuronidase positive Escherichia coli in the food samples, inoculated plates are incubated:

Answer 9

At 44*C for 18-24 hours

Question 10

Microorganisms who represent a high risk to the individual but low risk to the community belong to:

Answer 10

Risk category 3

Question 11

The name of culture medium used for enumeration of yeasts and moulds in food products with water activity greater than 0.95 is:

Answer 11

DRBC

Question 12

In terms of food safety, Staphylococcus aureus is:

Answer 12

A toxinogenic bacterium

Question 13

The following quantity of the test sample is used for preparation of the initial suspension during quantitative microbiological examination:

Answer 13

1 gram (with 9 gram peptone salt solution)

Question 14

A positive result of PREMI test (the presence of residues of inhibitory substances in food samples) is manifested by:

Answer 14

Blue/violet colouration of the tube content (inactive bacteria)

Question 15

Negative PREMI test:

Answer 15

Yellow colouration of the tube content (active bacteria)

Question 16

Based on optimum growth temperature, Listeria monocytogenes belongs to:

Answer 16

Psychrotrophs

Question 17

The typical colonies of Staphylococci on the surface of Baird-Parker agar are:

Answer 17

Black or grey surrounded by a clear zone which may be partially opaque, sometimes an oppalescent ring immediately in contact with the colonies may appear in this clear zone