FSC-342 Quiz #1: Lecture 2 - The Trajectory of Food Microbiology

What is microbiology?

The study of microscopic organisms.

What is food microbiology?

A subdivision of microbiology that studies microbes that grow or survive in food and how food environments affect them.

What are the three major areas of food microbiology?

Foodborne disease, Food spoilage, and Food fermentation.

How has the number of recognized foodborne pathogens changed in the past 20 years?

It has doubled.

What historical events led to the development of HACCP?

The presence of foodborne pathogens and the need to prevent contamination.

What U.S. act introduced hazard analysis and risk-based preventive controls for food safety?

The Food Safety Modernization Act (FSMA).

Why is food microbiology described as being "at the beginning"?

Because more pathogens are expected to emerge, and preparedness is essential.

What are the main activities of food microbiologists?

Detection, prediction, product creation, manipulation, and development of microbes.

What does detection and quantification involve for food microbiologists?

Detecting, identifying, and quantifying microorganisms in food.

What does prediction involve for food microbiologists?

Predicting the growth and survival of microbes based on food’s intrinsic and extrinsic parameters.

How can food microbiologists create foods that microbes “don’t like”?

By lowering water activity or using thermal treatments.

How do food microbiologists manipulate microbes?

By enhancing beneficial microbial growth (fermentation) or eliminating pathogens using physical, chemical, or biological methods.

What do food microbiologists develop for healthy food production?

New microbes or probiotic strains.

What was approve for pathogen control in meat and poultry?

Irradiation.

What was approved for pathogen control in shell eggs, lettuce, and spinach?

Irradiation and High Pressure Processing (HPP).

What are the three main areas of current and future food microbiology research?

Food spoilage, Food fermentation, and Foodborne pathogens.

What causes food spoilage?

Spoilage organisms that can grow at refrigeration temperatures.

How much of the world’s food is lost to spoilage?

About one-third.

What are future goals in food spoilage research?

Identifying and controlling spoilage microbes, reducing spoilage in refrigerated foods, and analyzing microbial communities.

What causes food fermentations?

Beneficial bacteria and some molds.

What is food biopreservation?

The use of food-grade microbes and their antimicrobial metabolites to preserve food.

What are foodborne pathogens?

Harmful microbes that cause illness (e.g., Salmonella, Listeria, Hepatitis A virus).

What are viruses?

Non-cellular infectious agents that infect humans, animals, plants, insects, and bacteria.

Can viruses replicate outside a host?

No, they require a host to replicate.

What are the main shapes of viruses?

Helical, Polyhedral, and Complex.

Give three examples of foodborne viruses.

Hepatitis A, Astrovirus, Rotavirus.

What are bacteria?

Small, generally unicellular prokaryotic microorganisms 0.4–1.5 µm in size.

Why are bacteria considered prokaryotic?

They lack a nuclear membrane, mitochondria, and other organelles.

What are the main components of a bacterial cell wall and membrane?

Cell wall: protein, lipid, and peptidoglycan; Cell membrane: lipid bilayer for respiration.

What nutrients do bacteria require for growth?

Carbohydrates, carbon, nitrogen, vitamins, minerals, sulfur, and phosphorous.

What physical factors affect bacterial growth?

Water activity, temperature, and pH.

What is the Gram stain reaction?

A method that classifies bacteria as Gram-positive (purple) or Gram-negative (pink).

What causes the difference in Gram stain results?

Differences in bacterial cell wall structure.

What are the main bacterial shapes (morphology)?

Rod-shaped and spherical.

What are bacterial spores?

Resilient structures formed by some bacteria; can be central, terminal, or subterminal.

What are the two major pathogenic spore-forming genera?

Bacillus and Clostridium.

What are flagella and their types?

Structures used for movement; can be polar or peritrichous.

Name a Gram-positive rod that is non-spore forming.

Listeria monocytogenes.

Name Gram-positive spore formers.

Aerobic: Bacillus cereus; Anaerobic: Clostridium perfringens, Clostridium botulinum.

Name a Gram-positive coccus that causes food poisoning.

Staphylococcus aureus.

Name examples of Gram-negative rods (Enterobacteriaceae).

Salmonella spp., Shigella spp., Escherichia coli, Yersinia spp.

Name two examples of Gram-negative non-Enterobacteriaceae.

Vibrio spp. and Campylobacter spp.

What are characteristics of Vibrio spp.?

Aerobic, curved rod with polar flagella; examples include V. cholera and V. parahaemolyticus.

What are characteristics of Campylobacter spp.?

Microaerobic, curved rod with polar flagella; examples include C. jejuni and C. coli.

What are fungi?

Eukaryotic organisms with a nucleus and organelles.

What distinguishes fungi from bacteria?

Fungi are eukaryotic with a nuclear membrane; bacteria are prokaryotic without one.

What harmful compounds can some fungi produce?

Mycotoxins.

What are the two main types of fungi?

Molds (multicellular) and Yeasts (unicellular).

Name two beneficial molds used in cheese production.

Penicillium roqueforti (blue cheese) and Penicillium camemberti (Camembert).

Name some foods commonly spoiled by molds.

Cheese, fruits, vegetables, grains, baked goods, jams, and jellies.

What are parasites?

Intracellular pathogens larger than bacteria that do not proliferate in food.

Are parasites culturable in foods?

No, they are non-culturable.

Name three protozoan parasites that cause foodborne illness.

Cryptosporidium parvum, Cyclospora cayetanensis, Giardia lamblia.