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?