Negative impact on microbial growth Flashcards
what chemoorganotrophic microbes
oxidise chemical compounds as a source of energy and carbon
perfect media is food
classification of food
perishable -short shelf life
semi-perishable
non-perishable - long shelf life
Define food borne disease
disease that is infectious or toxic in nature caused by agents that enter the body through ingestion of food
what is the largest food borne microbe causing death in UK
listeria Monocytogenes
tell statistic in UK of food borne illnesses
1 million/year suffer
22.000 are hospitalised
500 death
UK cost 1.5 billion pounds
what is an outbreak in statistic
2 or more people are affected by the same organism in the same location
what does the infection depend on
on host susceptibility and pathogenicity/virulence of microbe
what is virulence
pathogen’s ability to damage host
Food poisoning is a result of ….
consuming toxins the microbe has produced or toxins it has been injected with
Describe exotoxins
Toxins released extracellulary
enterotoxins- affect intestinal mucosa causing diarrhoea (Salmonella, prefringens, and E.coli )
cytotoxins- pathogen kills its own host ( E.coli and clostridium pref)
neurotoxins- interfere with normal neural transmission( botulinum)
describe endotoxins
lipopolysaccharide toxin, released from the outer membrane of gram - cell envelope by lysis
produced by salmonella and shigella
what is the difference between gram- and gram +
gram - has extra cell membrane for protection and stain remains purple when washed with alcohol
describe pre-formed toxins
when organism grows in the food itself- toxin inside the food
does not require person to person spread
short incubation time
Ex: staphylococcus aureus and bacillus serum - emetic syndrom( rice)
Describe Non Invasive infection
colonises intestinal lumen , mainly small intestine
attaches via fimbriae
E.coli, perfringes
Invasive infection
invade cells in intestinal epithelium, remain there and pass to epithelial cells through lamina proprio
Salmonella
