Food Microbiology

microorganisms can be _____ & _____

beneficial and destructive

food

an ecosystem for microorganisms

factors affecting growth of microorganisms in food

1. Extrinsic Parameters

2. Intrinsic Parameters

Intrinsic Parameters

1. nutrients

2. pH

3. aw

4. Eh

5. inhibitory substances

organism with the widest pH range

molds

pH range of microorganisms in descending order

1. molds

2. yeasts

3. bacteria

pH range of molds

0.5-11

pH range of yeasts

1.5-8.5

pH range of Alicyclobacillus spp.

2-6

pH range of Salmonella spp.

3.75-9.5

pH range of Acetobacter spp.

4-9.25

pH range of Listeria monocytogenes

4.25-9.75

pH range of E. coli

4.25-9

pH range of Clostridium botulinum

4.5-8.5

pH range of Bacillus cereus

5-9.5

pH range of Campylobacter spp.

5-9

pH range of Shigella spp.

5-9.1

pH range of Vibrio parahaemolyticus

5-11

pH range of Vibrio cholerae

5-9.5

pH range of Clostridium perfringens

5-8.5

Water activity (aw)

• measure of unbound water

• aw = p/p0

  • p = food

  • p0 = water

    • requirements : equilibrium and constant T & P

aw requirement of most spoilage bacteria

0.9

aw requirement of most spoilage yeasts

0.88

aw requirement of most spoilage molds

0.80

aw requirement of Halophilic bacteria

0.75

aw requirement of Xerophilic molds

0.61

aw requirement of Osmophilic yeasts

0.61

Oxidation-Reduction Potential (Eh)

ease of losing or gaining electrons

Eh

Extrinsic Parameters

1. Relative Humidity

2. Temperature

3. Gases

4. Other microorganisms

Food microbiology

scientific study of microorganisms in food and used in food

role of microorganisms in food

• food itself

• used in food production

• spoilage aand decomposition

Microorganisms as Food

• Fusarium venenatum

• Marmite

• Vegemite

• Chlorella

• Arthrospira

Fusarium venenatum

Vegan Quorn

Brewer's Yeast

• Marmite

• Vegemite

Arthrospira

Spirulina Filipina

Microorganisms in food production

Fermentation

• Fungi

• Bacteria

Fermentation

• improve shelf life and organoleptic properties of food

• increase in vitamin content and improve digestibility of raw foods

wine

fungi and fermentation

pale ale

fungi and fermentation

instant dry yeast

fungi and fermentation

bread

fungi and fermentation

cacao seeds

fungi and fermentation

Aspergillus oryzae

koji

miso paste

fungi and fermentation

Sake (?) Tentaka

fungi and fermentation

soy sauce

fungi and fermentation

penicillium

fungi and fermentation

P. camemberti

Cheese

P. roqueforti

blue cheese

gouda cheese

bacteria and fermentation

sour cream

bacteria and fermentation

yogurt

bacteria and fermentation

yakult

bacteria and fermentation

pickles

bacteria and fermentation

salami

bacteria and fermentation

spoilage

• unfitness of food for human consumption

• chemical or biological

microbial spoilage

• growth of microorganisms + action of their enzymes

Foodborne illnesses

• infection

• toxico-infection

• intoxication

infection

• ingestion of food contaminated with pathogens

Salmonellosis

infection inducing pathogen

Campylobacteriosis

infection inducing pathogen

EIEC infections

infection inducing pathogen

Listeriosis

infection inducing pathogen

Norovirus infection

infection inducing pathogen

Hepatitis

infection inducing pathogen

Intoxication

• ingestion of food containing toxins produced by microorganisms

foodborne botulism

intoxication

Staphylococcal food poisoning

intoxication

Emetic syndrome

intoxication

ingestion of mycotoxins

intoxication

toxicoinfection

• infection + intoxication

Perfringes poisoning

toxicoinfection

Diarrheal illness of B. cereus

toxicoinfection

STEC toxicoinfection

toxicoinfection

Cholera

toxicoinfection

food preservation

prevent/delay microbial activity

food preservation strategies

1. direct removal (washing and filtration)

2. keeping out microorganisms (aseptic tech., effective food packaging)

3. killing of microorganisms (heat and chemicals)

4. inhibiting growth (low temp. storage)

hurdle concept

• uses multiple preservation methods (like heat, acidity, drying, or refrigeration) to control microbial growth in food

• each method acts as a "hurdle" that stresses or blocks microbes, making it harder for them to survive or multiply.

food safety

freedom from agents that can cause illnesses

Good Hygiene Practices (GHPS)

best practices that provide guidance and protocols to be followed in food production chain

Hazard Analysis and Critical Control Points (HACCP)

• identifies the steps in food production that are crucial in limiting food safety incidents

Hazard Analysis and Critical Control Points (HACCP)

1960 development by Pilsbury, US Army Lab., and NASA for the space program

1969

First HACCP implementation

7 Principles (HACCP)

1. Hazard analysis

2. Determine Critical Control Points (CCPs)

3. Establish Critical Limits

4. Establish Monitoring Procedures

5. Establish Corrective Actions

6. Establish Verification Procedures

7. Record-keeping and Documentation

Laws about food safety

R.A. No. 10611

Food Safety Act of 2013

quote galing dun sa batas

“protect the public from foodborne and waterborne illnesses and unsanitary, unwholesome, misbranded, or adulterated foods”

home food safety

1. clean

2. separate

3. cook

4. chill

career opportunities

1. industry

2. research

3. diagnostics / biosafety

4. academe