Microbiology Flashcards

Difference between spoilage bacteria and pathogens

Spoilage bacteria make food smell taste or look bad but are usually not dangerous Pathogens cause illness but don’t always affect appearance.

Infection in terms of foodborne illness

Ingesting live bacteria that multiply in the gut and cause illness e.g. Salmonella.

Intoxication in foodborne illness

Sickness caused by preformed toxins in food not the bacteria themselves e.g. Staph aureus.

Enterotoxin

Toxin released by bacteria after they grow in the gut e.g. E coli O157:H7 Clostridium perfringens.

Populations most susceptible to foodborne pathogens

Infants elderly pregnant women and immunocompromised individuals chemo HIV.

Key features of Staphylococcus aureus

Poor handling hygiene causes intoxication symptoms appear in 1–7 hours.

Key features of Listeria monocytogenes

Found in ready to eat and deli meats infection onset 3–70 days dangerous in pregnancy.

Key features of E coli O157:H7

Found in ground beef enterotoxin onset 3–8 days risk of HUS in children.

Key features of Salmonella

Found in poultry pork eggs infection onset 12–72 hours.

Key features of Clostridium perfringens

Found in buffet lines hot holding foods enterotoxin onset 8–14 hours.

Key features of Campylobacter

Found in poultry infection onset 2–5 days.

Difference between sterilization pasteurization and cooking

Sterilization kills all microorganisms Pasteurization reduces pathogens to safe levels Cooking makes food safe to eat but not sterile.

Effect of ambient temperature on bacterial growth

Higher temperatures equal faster growth.

Bacterial growth phases

Lag phase bacteria adjusting Log phase exponential growth.

Danger zone for bacterial growth

40–140°F.

Modes of transmission for foodborne viruses

Fecal oral contaminated hands water e.g. Norovirus.

Transmission of Trichina

From undercooked pork or wild game bear boar.

Pathogen commonly found in raw oysters

Vibrio parahaemolyticus.

Why meat is an ideal environment for microbes

High water content rich protein near neutral pH plus minerals and some carbohydrates