Pathogenic Bacteria Associated with

Different Categories of Food Products

Venue: Beirut, 2-3 March 2015

TAIEX expert: Dr.sc.ing. Tatiana Marcenkova,

Riga, Latvia, Europe

TAIEX Workshop on shelf-life determination techniques for food

products [AGR 55007] in cooperation with Consumer Protection

Directorate, Ministry of Economy and Trade of Lebanon.

Microbial Hazards 2

Microbial Hazards

Microorganisms are everywhere -- they can

be:

– Pathogens – cause disease

– Spoilers – cause the quality of food to

deteriorate

– Beneficial – used for food production and

present in and on the body

Microbial food poisonings

Intoxications or toxicosis

Bacterial toxicosis

Mycotoxicosis

-ochratoxin A,B,C

-patulin

- mycotoxins A, B...

Toxicoinfections

Potentially pathogenic bacteria:

1) Enterobacteriaceae;

2) Vibrionaceae;

3) Pseudomonadaceae;

4) Streptococcaceae;

5) Bacillaceae (Bacillus, Clostridium)

3

Non-microbiological food poisonings

Poisonous food

Plant origin Animal origin

Poisonous or toxic ingredients

of food

Inorganic Organic Radionuclide's

4

Microbial Hazards 5

Types of Foodborne Illness

Infection – eating food contaminated with pathogens

Intoxication – eating food contaminated with the toxins (poisons)

formed by bacteria

– eating food contaminated with other biological or chemical toxins (poisons)

Toxin-mediated infection – eating food contaminated with pathogens that grow

in the body and form toxins (poisons)

Microbial Hazards 6

Three Microbial Hazards

Three microorganisms

cause most foodborne

illness:

– Bacteria

– Viruses

– Parasites

Microorganisms are:

– naturally present or

– get into the food through

poor handling practices.

Pathogens

Common types of pathogens

What is pathogenic bacteria?

• path·o·gen (păth′ə-jən), noun

An agent that causes disease, especially a virus, bacterium, or fungus.

• path•o•gen (pæθ ə dʒən, -ˌdʒɛn), noun

Any disease-producing agent, esp. a virus, bacterium, or other

microorganism.

Source: http://www.thefreedictionary.com/pathogen

• Pathogens – are disease causing microorganisms, such as bacteria,

fungi, and viruses, found commonly in sewage, hospital waste, run-off

water from farms, and in water used for swimming.

• Most pathogens are parasites (live off the host) and the diseases they

cause are an indirect result of their obtaining food from, or shelter in,

the host. Larger parasites (such as worms) not called pathogens.

Source:

http://www.businessdictionary.com/definition/pathogens.html#ixzz3PMfT7

ozU

RASSF – rapid alert system for food

and feed (regulation 178/2002)

10

11

1 – biological

2 – chemical

3 – physical

(foreign bodies)

http://ec.europa.eu/food/safety/rasff/docs/rasff_annual_report_2013.pdf

RASFF notifications on

microorganisms in food

http://ec.europa.eu/food/safety/rasff/docs/rasff_annual_report_2013.pdf

RASFF notifications on mycotoxins in

food and feed

Source:

http://ec.europa.eu/food/safety/rasff/docs/rasff_annual_report_2013.pdf

Most common zoonoses in EU

Source: http://www.ecdc.europa.eu/en/Pages/home.aspx

Most common zoonoses in EU

Most common zoonoses in EU

Detection of Food-Borne Pathogens

• must be rapid and sensitive

• methods include:

– culture techniques – may be too slow

– immunological techniques - very sensitive

– molecular techniques

• probes used to detect specific DNA or RNA

• sensitive and specific

comparison of PCR and

growth for detection of

Salmonella

nucleic acid can be detected

even when plaque-forming

ability is lost

21

Derīguma termiņa noteikšana

Kvalitātes

pasliktināšanās

Uzglabāšanas laiks noteiktā temperatūrā

Nemikrobioloģiska

kvalitāte

Derīguma

termiņa beigas

Derīguma

termiņa beigas

Mikrobioloģiska

kvalitāte

I781 - 2002-2003 22

4. Overview of hazards in foods

• Definition of a hazard – A physical, chemical or (micro)biological property of a food…

• that may cause it to be unsafe for consumption

• That is reasonably likely to cause illness or injury in the absence of its control (NACMCF)

• Biological hazards – Macrobiological hazards: very uncommon

example: poisonous insect remark: macrobiological organisms may carry microbiological hazards!

– Microbiological hazards:

• Microbiological hazards – Bacteria (see separate detailed overview)

– Viruses: Hepatitis A; small round structured viruses (SRSV),… • particularly in shellfish: concentrate viruses from contaminated water

• Control: hygiene to prevent transmission; heating (pasteurisation) to inactivate

I781 - 2002-2003 23

4. Overview of hazards in foods (2) – Protozoa

• Toxoplasma: meat or milk from (or contact with) infected animals

• Giardia / Cryptosporidium: mainly through fecally contaminated water

• Control: heating (pasteurisation) or chemical disinfection of water to inactivate

– Mycotoxins • Secondary metabolites of some fungi: aflatoxins, patulin, ochratoxin…

• Behave as chemical hazards once they are produced

• Main problem is presence in raw materials, e.g. cereals, nuts

• Can be formed in the field due to fungal infection of crop, or post-harvest when drying is too slow

– Parasites: Flatworms, tapeworms • Mainly in meat and fish

• Control: heating (pasteurisation) or freezing to inactivate

I781 - 2002-2003 24

Heat stability Psychrotroph (growth 4°C)

Infectious Dose (ID)

Toxin producers

Staphylococcus aureus Bacillus cereus - emetic

- diarrhoeal

Clostridium botulinum

- proteolytic

- non-proteolytic

(toxin)

HS (min@100°C)

HS

HL

HL

HL

N

N/Y

N/Y

N

Y

Organism must grow to high numbers (>106) to form

enough toxin to cause disease

Spore formers

B. cereus C. botulinum - proteolytic

- non-proteolytic

C. perfringens

(spores)

Intermediate

12D = 3’@120°C

6D = 10’@90°C

Intermediate

N

~107

Overview of bacterial pathogens

I781 - 2002-2003 25

Heat stability Psychrotroph (growth 4°C)

Infectious Dose (ID)

Low ID infective pathogens

Salmonella Shigella Escherichia coli VTEC (e.g. O157:H7)

Campylobacter

< L. mono < L. mono < L. mono

< L. mono

N

N

N

N

102 or less

102 or less

102 or less

102 or less

High ID infective pathogens

Listeria monocytogenes Yersinia enterocolitica C. perfringens Other E. coli

6D = 2’@70°C

< L. mono sporeformer

< L. mono

Y

Y

N

N

~106 (less for YOPI)

~106

~107

~106

Overview of bacterial pathogens (2)

26

Thank you! Questions?