FH1 mt 1

Question 1

What is the effect of increasing NaCl concentration on water activity ?

• It has no effect on water activity
• It is increasing the water activity
• It is decreasing the water activity
• The effect on water activity is not linear

Answer 1

• It is decreasing the water activity

Question 2

Which group of these microorganisms can multiply at the highest water activity level ?

• Gram positive bacteria
• Gram negative bacteria
• Yeasts
• Moulds

Answer 2

• Gram negative bacteria

Question 3

Choose the correct statement !
- Except infants, the botulinum toxin is produced in the food
- The botulinum toxin is produced in the GI tract of the
consumer
- The exotoxin of Clostridium perfringens is produced in the food
- The exotoxin of Staphylococcus aureus is produced in the GI tract of the consumer

Answer 3

• Except infants, the botulinum toxin is produced in the food

Question 4

Choose the correct statement!
- Beta-agonists are banned substances in the veterinary
medicine
- Androgens are banned substances in the veterinary
medicine
- Beta-agonists are banned for growth promotion, but can be
used for treatment of animals
- Nitrofurans are banned for growth promotion, but can be
used for treatment of animals

Answer 4

• Beta-agonists are banned for growth promotion, but can be

used for treatment of animals

Question 5

Which test is positive for Salmonella?

• Lactose fermentation
• Hemolysis
• Antigen-antibody reaction
• Coagulation

Answer 5

• Antigen-antibody reaction

Question 6

Which European regulation describes the microbiological criteria of foodstuffs ?

• 852/2004 EC
• 2033/2017 EC
• 2073/2005 EC
• 2033/2003 EC

Answer 6

• 2073/2005 EC

Question 7

Which sugar(s) can be fermented by Salmonella spp.?

• Glucose
• Lactose
• Sucrose
• None of the above

Answer 7

• Glucose

Question 8

Which of these steps is necessary during the creation of a 10- fold serial dilution ?

• Mixing the tubes with the vortex before pipetting from them
• Changing the pipette tip between each dilution
• All of the above
• None of the above

Answer 8

• All of the above

Question 9

What happens to the redox potential of the medium during the bacteria’s multiplication ?

• It always increases
• It always decreases
• It usually decreases, but some obligate anaerobes increase it
• It usually increases, but some obligate aerobes decrease it

Answer 9

• It always decreases

Question 10

Choose the correct statement!

• Endotoxins produced by microorganisms in the food cause food infection
• Endotoxins produced by microorganisms in the food cause food poisoning
• Exotoxins produced by microorganisms in the food cause food infection
• Exotoxins produced by microorganisms in the food cause food poisoning

Answer 10

• Exotoxins produced by microorganisms in the food cause food poisoning
  (Endotoxins are not released until the bacteria are killed
  by the immune system)

Question 11

Choose the correct statement !

• Salmonellae are psychrophilic bacteria
• Campylobacter jejuni is a psychrophilic bacterium
• Listeria monocytogenes is a psychrophilic bacterium
• Staphylococcus aureus is a psychrophilic bacterium

Answer 11

• Listeria monocytogenes is a psychrophilic bacterium

Question 12

Which bacterium should we use for the positive CAMP-test of Listeria monocytogenes ? (several answers)

• Staphylococcus aureus
• Rhodococcus equii
• Listeria ivanovii
• Escherichia coli

Answer 12

• Staphylococcus aureus

Question 13

What is the lowest pH for the growth of Salmonella enterica?

• 7.8
• 5.8
• 3.8
• 1.8

Answer 13

• 3.8

Question 14

Which group of microorganisms were proved to be inhibited by sorbic acid at pH 4.5 during our practice?

• Bacteria
• Yeasts
• Moulds
• None of them

Answer 14

• Yeasts

Question 15

What parameter is affecting the dissociation level of organic acids used for preservation the most?

• Temperature
• Osmotic pressure
• Humidity
• pH

Answer 15

• pH

Question 16

Which test is negative for Escherichia coli?

• Indole
• Methyl red
• Citrate
• None of the above

Answer 16

• Citrate

Question 17

What could be a valid key number for the MNP method? - 333320

• 320
• 3.2
• 10-3

Answer 17

• 320

Question 18

Choose the correct statement!
- The main target organ of aflatoxins is the liver
- The main target organ of aflatoxins is the kidney
- The main target organ of aflatoxins is the cardiac muscle - The main target organ of aflatoxins is the central nervous
system

Answer 18

• The main target organ of aflatoxins is the liver

carcinogenic

Question 19

Choose the correct statement!
- Paralytic shellfish poison is a biotoxin produced by
bacteria
- Paralytic shellfish poison is a biotoxin produced by
microscopic algae
- Paralytic shellfish poison is a mycotoxin produced by
bacteria
- Paralytic shellfish poison is a mycotoxin produced by
microscopic algae

Answer 19

• Paralytic shellfish poison is a biotoxin produced by

microscopic algae

Question 20

Choose the correct statement! - Foodborne disease caused by Campylobacter jejuni are
diseases characterised by extraintestinal signs
- Foodborne disease caused by Salmonella enteritidis are
characterised by extraintestinal signs
- Foodborne disease caused by Yersinia enterocolitica are
characterised by extraintestinal signs
- Foodborne disease caused by Listeria monocytogenes are characterised by extraintestinal signs

Answer 20

• Foodborne disease caused by Listeria monocytogenes are characterised by extraintestinal signs

Question 21

Choose the correct statement!

• The exotoxin produced by Staphylococcus aureus is heat stable
• The botulinum toxin is heat stable
• The diarrhoeic toxin of Bacillus cereus is heat stable
• The exotoxin of Clostridium perfringens is heat stable

Answer 21

????

Question 22

Which bacterium can be detected with the Baird Parker plate ?

• Salmonella enterica
• Escherichia coli
• Enterococcus faecalis
• Staphylococcus aureus

Answer 22

• Staphylococcus aureus

Question 23

What is the basis of CAMP test in the Listeria monocytogenes confirmation?

• Agglutination
• Coagulation
• Haemolysis
• pH decrease

Answer 23

• Haemolysis

Question 24

Which ion makes the color reaction with the protein traces during the Biuret reaction?

• Chrome
• Magnesium
• Iron
• Copper

Answer 24

• Copper

Question 25

Which one is NOT a chapter of the 2073/2005 EC regulation? - Food safety criteria

• Process hygiene criteria
• Hazard analysis criteria
• Rules for sampling and preparation of test samples

Answer 25

• Hazard analysis criteria

Question 26

What can we detect with the Limulus-test ?

• Gram + bacterium enzymes
• Lipopolysaccharide of Gram positive bacteria
• Lipopolysaccharide of Gram negative bacteria
• Chilia proteins

Answer 26

• Lipopolysaccharide of Gram negative bacteria

Question 27

Choose the correct statement!
- Food hygiene is the basic system of requirements and
tools guaranteeing food safety
- Food hygiene is the basic system of requirements and
tools guaranteeing food quality
- Food safety is the basic system of requirements and tools
guaranteeing food hygiene
- Food quality is the basic system of requirements and tools
guaranteeing food hygiene

Answer 27

• Food hygiene is the basic system of requirements and

tools guaranteeing food safety

Question 28

Choose the correct statement!

• D value is the temperature increase needed for a decrease of the live cell count by one order of magnitude
• D value is the time needed for a decrease of live cell count by one order of magnitude
• Z value is the time needed for a decrease of live cell count by one order of magnitude
• Z value is the temperature reduction needed for a decrease of live cell count by one order of magnitude

Answer 28

• D value is the temperature increase needed for a decrease of the live cell count by one order of magnitude