Week 9C2 : food safety Flashcards
Wha are the 6 main causes of unsafe food?
- Presence of pathogen
- Presence of natural toxins
- Extraneous matter
- Environmental contaminants
- Harmful additives
- Allergens
What is the cause of the hamburger disease?
Emergence of E.coli O157:H7
What is the percentage of the population affected by food poisoning in the US?
30%
T or F: food microbiology adresses only the microbiological contamination to make the food safe
F it is also because food contamination is the leading cause of food loss/spoilage
What are the microorganisms of concern in food microbiology?
- Bacteria
2. Fungi (molds and yeasts)
T or F : viruses can cause food spoilage
false, but they can cause minor foodborne illnesses because they don’t prolifate in food.
What is the two main goals of food microbiology
- reducing spoilage
2. making food more safe
T or F : the microorganisms can be found equally in and on the tissues of the food
False, they are mostly found on the tissues
bacteria reproduce by ___, resulting in an
exponential rate of growth: population can double every ___ min
Binary fission
20-30
T or F : fungus and bacteria reproduce by binary fission
False, only bacteria does
What is the standard for grade A raw milk prior to pasteurization
100 000 bacteria per milliliter
What are the three shapes of bacteria?
spherical, rod shape and spiral
What are the dimensions of bacteria?
1-4µm
What are the dimension of yeast?
20µm
What are the shapes of yeast?
spherical and ellipsoidal
Which microorganism is mostly used in fermentation
yeast
What is the multicellular form of molds ?
Hyphae
Which of the microorganism is a common spoilage cause?
molds
How does the microorganisms degrade food ?
by excreting enzymes
___ are generally better at growing at lower moisture levels than other microorganisms
Molds
Mesophilic organisms best over a temperature range of ___
20- 45°C
Thermophilic (heat-loving) organisms grow best at temperatures above___ , some are able to grow at temperatures up to __
45°C
82˚C
Psychrophilic (cold-loving) organisms grow best at ___
low temperatures (<10°C)
Psychrotrophic organisms are able to grow at ___
refrigerator temperature (~4°C).
____ grow in the absence of oxygen.
Anaerobes
___ grow in the presence of oxygen.
Aerobes