Lecture 1. Food Microbiology and Food Related Pathogens Flashcards
What are the three types of food borne disease?
Infection (bacterial, fungal, eukaryotic parasites, viruses)
Intoxication (bacterial and fungal toxins, shellfish toxins, metals, chemicals)
Allergy (usually specific proteins)
What is the causative chain of infection?
Agent → Source → Contamination → Suitability → Growth conditions → Consumption
What can food contamination be?
Biological, physical, chemical or allergen
What are the four sources of food contamination?
Food handler associated
Food processing
Food storage
Food product
How can food handler’s be a source of contamination?
Inadequate personal hygiene, faecal contamination
How can food processing be a source of contamination?
Equipment, packaging, personnel contamination
How can food storage be a source of contamination?
Time and temperature
How can food product be a source of contamination?
Meat and poultry – Contaminated feed, animal-animal transmission
Surface contamination (fur/feathers/hooves)
Fish and Shellfish - contamination sewage/water
Produce contaminated - contaminated irrigation water
Soil contamination
Compromised Seafood
Accumulate high levels of water associated bacteria (Crusataceans/molluscs)
Consumption of contaminated organisms (Crustaceans/fish)
Surface contamination from water related pathogens (Fish)
Susceptible to temperature abuse (retailer and customer)
Compromised meat and poultry
High levels of bacteria naturally found within organism (Poultry)
Cross contamination during processing (ready-to-eat meat and poultry)
High count of contact points in processed meats
Non-thermally treated products (Sausages)
Benefits of using microbes with food
Food enhancement (cheese, meat, wine and beer)
Food additives (food safety and stability, probiotics)
Drawbacks of using microbes with food
Food spoilage (shortened shelf life, failure to meet legal requirements)
Food safety (morbidity, mortalitly)
What is the food factor of Lactobacillus acidophilus?
Pro-biotic, yogurts, kefir, miso, sauerkraut, cheese
What are the four intrinsic treatments that preserve food?
Treatment: water activity, Action: growth inhibition
Treatment: pH - food acidity, Action: growth inhibition
Treatment: antimicrobial chemicals, Action: various
Treatment: biological (competitive mircoflora, bacteriocins, enzymes), Action: vaious
What are the four extrinsic treatments that preserve food?
Treatment: heat treatment, Action: destruction of cells and spores
Treatment: low temperature storage, Action: growth inhibition
Treatment: modified atmosphere packaging, Action: growth inhibition/destruction of cells
Treatment: radiation (UV, microwave, gamma), Action: destruction of bacterial cells
What is hurdle technology?
A number of preservation factors that are combined to improve food safety
What does hurdle technology allow?
Individual measures to be milder; increasing ‘naturalness’ of food
Is hurdle technology more effective than individual processing methods?
Yes
How many hospitalisations occur annually in the UK due to food-borne diseases?
~20,000
How many deaths occur annually in the UK due to food-borne diseases?
~500
What are the four main food-related pathogens?
Salmonella sp.
Campylobacter jejuni
Listeria monocytogenes
Escherichia coli
Where is salmonella found?
In the intestinal tract of birds and other animals
How does human contamination occur due to salmonella?
Through consumption of contaminated animals, animal products or water
What does salmonella result in?
Gastroenteritis or typhoid fever depending upon the type of Salmonella encountered
