Foodborne Infections & Poisons

Question 1

What are the 5 main pathogens for concern when considering Foodborne infections?

Answer 1

Norovirus
Campylobacter spp.
Salmonella spp.
Listeria Monocytogenes
Escherichia Coli

Question 2

What is Norovirus and why is it such a prominent food borne infection?

Answer 2

Single stranded RNA calicivirus
Prominent because it only requires a small infective dose and is highly survivable in the environment

Question 3

How do we get rid of Norovirus on food surfaces?

Answer 3

Cooking past 80 degrees

Question 4

What is Campylobacter spp?
How would we culture it?

Answer 4

Gram negative rod
Culture faecal sample on blood/charcoal agar with antibiotics to supress the growth of non desirable pathogens

Question 5

What do we mean when we say Campylobacter is endemic in animals?

Answer 5

Carried sub clinically by birds and other animals so carcass contamination is very common

Question 6

How do we culture non typhoidal Salmonella?

Answer 6

culture faecal sample using enrichment broth (such as selenite)

Question 7

How do we serum type Salmonella?

Answer 7

Classify salmonella into serovars based on the surface antigens (aka Kauffmann White Scheme)

Question 8

Why does Listeria cause prolonged septicaemia?

Answer 8

It’s a facultative intracellular pathogen that invades and multiplies within mammalian cells- it can also cross the intestinal wall at the Peyer’s patches to enter the bloodstream and cause septicaemia.

Question 9

Which group are more likely to contract Listeriosis?

Answer 9

Pregnant women!

Question 10

What are the two toxins we should be aware of in Foodborne infections?

Answer 10

Staphylococcus aureus
Clostridium perfingens/ botulinum

Question 11

Why are steak burgers more likely to transmit foodborne disease than pieces of steak?

Answer 11

During the butchery process, as large cuts of meat are broken down into smaller portions, bacteria can be transferred along the way through cross-contamination- when meat is ground up, more of its surface area is exposed

Question 12

What is a requirement of a company wishing to sell Raw Milk?

Answer 12

Must register with the food standards agency

Question 13

What is a requirement of the farm wishing to sell raw milk? (3)

Answer 13

Animals must be free from brucellosis and tuberculosis
Farm must be routinely inspected twice a year
Milk must reach microbiological standards

Question 14

What are the microbiological requirements for raw pet food?

Answer 14

Salmonella must be completely absent
Enterobacterales should be below the cut off