biological hazards (microbioligcal)

microflora

- the community of microscopic organisms, such as bacteria, fungi, and protozoa, that live in a specific environment - like the human body, soil, or water

bacteria

- the primary microorganisms

- binary fission

binary fission

- a type of asexual reproduction where a single organism splits into two identical organisms

- commonly occurs in bacteria and other single-celled organisms

lag phase

- initial period of microbial growth curve

- when microorganisms are introduced to a food product and are adapting to the new environment

log phase

- second stage of the microbial growth curve

- where microorganisms undergo rapid, geometric multiplication

stationary phase

- third stage of microbial growth curve

- represents a period where the total # of living microorganisms remains relatively constant

- # of death - # of microorganisms multiply

death phase

- final stage of microbial growth curve

- characterized by an exponential decrease in the number of living organisms

- decline

- toxicity

factors affecting microbial growth

- intrinsic

- extrinsic

- implicit

intrinsic

- inherent physical, chemical, and biological properties of the food itself that influence microbial growth and spoilage

- food properties

- what is the pH?

- what is the water activity?

- how much nitrogen is present?

- are there enough minerals and vitamins?

extrinsic

- the environmental conditions surrounding the food that significantly influence the growth of microorganisms (bacteria, yeasts, molds, and the overall rate of spoilage)

- environmental

- what is the humidity of the storage area?

- what's the temperature of storage?

- is the oxygen present?

implicit

- the biological properties and interactions of the microorganisms themselves that affect their growth in food

- microorganisms and microbial interactions

nutrient content

- the chemical composition of a food item, specifically the amounts of essential substances it contains that are required fro life, growth, and health in both humans and mircoorganisms

- intrinsic factor

- how many nutrients are present int he food material?

- organic compounds = carbs, proteins, lipid, vitamins, minerals

pH

- pertains to the amount/concentration of hydrogens

- -log CH3O+ -> hydronium ion

- <7 = acidc

- >7 = basic

- 7 is neutral

- intrinsic factor

oxygen

- obligate aerobes

- facultative anaerobic

- anaerobic

- extrinsic

- obligate aerobes

- requires oxygen and pseudomonas

facultative anaerobic

- tolerates oxygen anaerobes and lactobacillus

anaerobic

- absence of oxygen clostridium (ex: canned foods)

water activity

- quantifies the free or unbound water available in a food product to support microbial growth and chemical reactions

- available for microbial growth

- bacteria (>0.90)

- yeasts/mold (<0.90) -> tolerate it

staphylococcus aureus ~ 0.86

- intrinsic

temperature

- extrinsic

- topt = optimal temperature

- temps in which they can grow is divided into 3 groups

- thermophiles

- mesophiles

- psychrophiles

thermophiles

- high temp

- >45 celsius

- lactobacillus (helps prevent infections from fermented dairy and vegetable products)

mesophiles

- moderate temo

- 20-45 celsius

- E. Coli

psychrophiles

- cold temp

- 20-45 celsius

- pseudomonas

implicit facts

- properties of microorganisms and their associations with eriche others

- antagonistic (antibiotics - can kill pathogens)

- synergisms/symbiotic (SCOBY - symbiotic culture/community of bacteria and yeasts)