Microbiology in Food Safety and Spoilage
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Questions and Answers

What is one way that microorganisms can transform a food's properties positively?

  • By causing foodborne illness
  • Through food spoilage
  • By fermenting food (correct)
  • By introducing pathogens

What is food spoilage primarily caused by?

  • High temperatures during storage
  • Excessive cooking
  • Chemical preservatives
  • Microorganisms using food as a nutrient source (correct)

Which of the following bacteria is known to be commonly found in undercooked poultry?

  • Clostridium perfringens
  • Salmonella (correct)
  • Listeria monocytogenes
  • Escherichia coli

What is the main consequence of food spoilage?

<p>Decreased nutritional value (B)</p> Signup and view all the answers

Which of the following is NOT a characteristic of foodborne illnesses?

<p>Always leads to severe illness (A)</p> Signup and view all the answers

How do microorganisms contribute to the deterioration of food?

<p>By synthesizing new compounds (C)</p> Signup and view all the answers

Which microbe is responsible for producing blue cheese?

<p>Penicillium roqueforti (D)</p> Signup and view all the answers

What negative effect can certain strains of E. coli cause?

<p>Severe diarrhea and abdominal cramps (D)</p> Signup and view all the answers

Which group of microorganisms is typically dominant in the atmosphere?

<p>Gram-positive rods and cocci (D)</p> Signup and view all the answers

What is a common characteristic of airborne fungi like Penicillium and Aspergillus?

<p>They produce large spores resistant to desiccation. (A)</p> Signup and view all the answers

Which of the following is commonly associated with soil microorganisms?

<p>Production of resistant structures (C)</p> Signup and view all the answers

What type of bacteria are often isolated from contaminated ocean waters?

<p>Enterobacteriaceae (B)</p> Signup and view all the answers

Which microorganisms are mentioned as being present on leaf surfaces?

<p>Phylloplane flora (C)</p> Signup and view all the answers

What is the main risk associated with consuming sea life from contaminated waters?

<p>Accumulation of enteric organisms (B)</p> Signup and view all the answers

What types of microorganisms are commonly found in soil?

<p>Bacteria, fungi, protozoa, and algae (D)</p> Signup and view all the answers

Which fungal genus is known for causing food spoilage and is found in both air and water?

<p>Fusarium (B)</p> Signup and view all the answers

Which bacteria are recognized as Gram-negative rods that can affect plants?

<p>Pectobacterium (A)</p> Signup and view all the answers

What is a primary characteristic of the normal skin flora in animals?

<p>Presence of Staphylococcus, Corynebacterium, and Propionibacterium (A)</p> Signup and view all the answers

What kind of conditions can lead to opportunistic infections in the nose and throat?

<p>Extreme temperatures and overcrowding (B)</p> Signup and view all the answers

Which fungus is known to produce the carcinogenic metabolite aflatoxin?

<p>Aspergillus flavus (B)</p> Signup and view all the answers

What is a reason why most foods cannot be considered sterile?

<p>They naturally harbor micro-organisms and acquire transient flora (A)</p> Signup and view all the answers

What type of bacteria is commonly carried in the nose by humans and can produce powerful toxins?

<p>Staphylococcus aureus (B)</p> Signup and view all the answers

Which statement is true regarding the gut of animals?

<p>It supports both specialized and transient micro-organisms (D)</p> Signup and view all the answers

What is one method to ensure food safety and satisfy storage requirements?

<p>Destroy the present micro-organisms (C)</p> Signup and view all the answers

What is one of the intrinsic factors affecting microbial growth in food?

<p>pH level (C)</p> Signup and view all the answers

Which type of microorganisms are specifically studied in relation to food safety and spoilage?

<p>Bacteria, fungi, protozoa, and algae (C)</p> Signup and view all the answers

What percentage of the final grade does the online test account for?

<p>20% (B)</p> Signup and view all the answers

Which of the following describes food intoxication?

<p>Consumption of food contaminated with toxins produced by bacteria (A)</p> Signup and view all the answers

What aspect of microbial quality is justified for food safety?

<p>The level of contamination by pathogenic microorganisms (C)</p> Signup and view all the answers

When does the practical component of the course start?

<p>Week 2 (C)</p> Signup and view all the answers

Which of the following best defines food microbiology?

<p>The science of microorganisms as they relate to food production and safety (A)</p> Signup and view all the answers

What is the primary objective of the group presentation in the course?

<p>To demonstrate understanding of microbial growth factors (D)</p> Signup and view all the answers

What is the primary purpose of using food-grade microorganisms in food bioprocessing?

<p>To produce fermented food (D)</p> Signup and view all the answers

How do lactic acid bacteria (LAB) contribute to food biopreservation?

<p>By increasing the acidity in foods (A)</p> Signup and view all the answers

What defines probiotics in food?

<p>Live cells intended to support digestion (A)</p> Signup and view all the answers

What is the role of a starter culture in food processing?

<p>To initiate fermentation rapidly (D)</p> Signup and view all the answers

Where can viable microorganisms typically be found?

<p>In a wide range of habitats, including extreme conditions (B)</p> Signup and view all the answers

Which of the following is NOT a function of probiotics?

<p>Preventing food spoilage (A)</p> Signup and view all the answers

What is a likely outcome of adding Lactobacillus and Bifidus to milk intended for babies?

<p>Improved digestion and immunity (C)</p> Signup and view all the answers

What is a characteristic of food biopreservation?

<p>Utilizing beneficial bacteria to curb spoilage (C)</p> Signup and view all the answers

Flashcards

Food Microbiology

The scientific field that investigates the presence and significance of microorganisms (bacteria, fungi, protozoa, algae) across the entire food production process, from farm to table.

Intrinsic Factors

The factors within the food itself that influence the growth and survival of microorganisms. Examples include pH, moisture content, nutrients, and the presence of antimicrobial compounds.

Extrinsic Factors

Factors outside the food that affect microbial growth, such as temperature, humidity, and the presence of oxygen.

Food Spoilage

The breakdown of food by microorganisms, leading to undesirable changes in taste, smell, texture, and appearance.

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Coliforms

A group of bacteria commonly found in the intestines of humans and animals. Their presence in food indicates potential fecal contamination, which could be harmful.

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Indicator Organisms

Organisms that indicate the presence of potential pathogens in food. Their presence does not necessarily mean that food is harmful, but it suggests increased risk.

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Food-borne Diseases

Illnesses caused by consuming food contaminated with harmful microorganisms. These are usually classified as food infections or food intoxications.

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Microbial Control in Food

Methods used to control the growth and survival of microorganisms in food, including heat treatment, irradiation, and proper storage conditions.

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Food Bioprocessing

Using organisms to make food. Think of bacteria turning milk into yogurt.

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Food Biopreservation

Beneficial microbes fighting off bad microbes to keep food fresh.

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Probiotics

Live microorganisms that improve your health, often found in yogurt or fermented foods.

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Starter Culture

A concentrated preparation of live cells used to speed up fermentation.

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Diversity of Microorganisms

A range of environments where microorganisms can thrive.

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Antimicrobial Metabolites

Substances released by beneficial bacteria to control harmful microbes.

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What are food microorganisms?

Microscopic organisms found on food, originating from the food source or introduced during processing, storage, and distribution.

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What is food spoilage?

Changes in a food's appearance, taste, smell, or texture that make it undesirable to eat, often caused by microorganisms.

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How do microorganisms cause food spoilage?

Microorganisms using the food's nutrients for their own growth, leading to changes in the food compound or production of off-flavors.

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What are foodborne diseases?

Illnesses caused by consuming contaminated food, often due to harmful bacteria or viruses.

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What is Salmonellosis?

A type of foodborne illness caused by the Salmonella bacteria, often found in contaminated poultry.

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What is Campylobacteriosis?

A type of foodborne illness caused by the Campylobacter bacteria, often found in contaminated poultry.

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What is Escherichia coli (E.coli)?

A bacteria species that can cause foodborne illness, often found in contaminated meat.

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What is fermentation?

Process where microorganisms help transform food into something desirable, like cheese, yogurt, or bread.

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Airborne Microflora

Microorganisms, particularly bacteria and fungi, found in the air. They're usually not abundant unless there's been contamination from human or animal sources.

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Dominant Airborne Bacteria

Gram-positive bacteria, like Bacillus and Streptomyces, often dominate the airborne microflora.

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Common Airborne Fungi

Fungi like Penicillium and Aspergillus are notorious for causing food spoilage, and are often found in the air.

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Soil Microflora

Soil is a complex environment teeming with bacteria, fungi, protozoa, and algae. These organisms are often involved in food spoilage due to their ability to break down complex organic matter.

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Resistant Soil Microbes

Bacteria and fungi in soil produce resistant structures to survive harsh conditions like changes in acidity, temperature, and moisture.

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Marine Bacteria

Bacteria isolated from seawater often require salt and are adapted to the low temperatures and nutrient levels of the ocean.

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Contaminated Water Flora

Contamination of water with sewage or other human activities can introduce enteric bacteria, like those found in the Enterobacteriaceae family, into aquatic environments.

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Plant Surface Microbiota

Microorganisms on the surface of leaves (phylloplane) and roots (rhizoplane) include a diverse population of bacteria, fungi, and yeasts.

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Plant Surface Bacteria

Gram-negative rods like Pectobacterium, Erwinia, Pseudomonas and Xanthomonas, well adapted to thriving on plant surfaces.

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Fermented Vegetable Bacteria

Lactobacillus and Leuconostoc are known for their role in the fermentation process, turning veggies into sauerkraut.

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Aspergillus flavus

A fungus capable of producing aflatoxin, a carcinogenic metabolite, potentially infecting crops before and after harvest.

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Animal Microflora

A diverse community of microorganisms that live on animals, some are specialized to the host, while others are temporary.

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Skin Microenvironment

The skin's surface is generally not favorable for most microbes due to its dryness and low pH.

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Dominant Skin Bacteria

Staphylococcus, Corynebacterium and Propionibacterium are dominant Gram-positive bacteria found on the skin.

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Nose and Throat Microbiota

The nose and throat, with their mucous membranes, are home to a distinct group of microorganisms.

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Staphylococcus aureus and Vomiting

Staphylococcus aureus, found in the nose, can produce a toxin that causes vomiting.

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Study Notes

Course Content

  • Week 1: Introduction to food microbiology (Face-to-Face)
  • Week 2: Intrinsic factors affecting microorganism growth and survival in food (Online)
  • Week 3: Extrinsic factors affecting microorganism growth and survival in food (Online)
  • Weeks 4-5: Microbial spoilage of different foods, Coliforms and indicator organisms (Online)
  • Week 6-8: Food-borne diseases (food infection), causative agents, symptoms, prevention (Online, Practical ends Week 6)
  • Weeks 9-10: Food-borne diseases (food intoxication), causative agents, symptoms, prevention (Online)
  • Weeks 11-12: Methods used to control microorganisms in food and food processing (Face-to-Face)
  • Week 13: Group Presentation (Pre-recorded)
  • Week 14: Final Exam

Assessment

  • Online Test: 20%
  • Final Exam: 50%
  • Presentation: 10%
  • Laboratory Assessment: 20%
  • Total: 100%

Outcomes

  • Explain factors affecting microbial growth in food, types of microorganisms influencing food quality, spoilage, and poisoning.
  • Justify appropriate microbial quality in food safety for microorganisms.
  • Explain lab techniques for microbial analysis on microbial quality and food safety.

The Scope of Food Microbiology

  • Microbiology studies the occurrence and significance of bacteria, fungi, protozoa, and algae from the start to the end of the food chain.
  • The food chain describes the processes of food growth, production, sale, and consumption.

Microorganisms and Food

  • All foods contain microorganisms.
  • Microorganisms originate from raw materials, harvesting/slaughter, processing, storage, and distribution.
  • Generally, these microorganisms have no effect on food or humans.
  • Some can cause spoilage.
  • Some can cause foodborne illness.
  • Some can beneficially change food properties, such as in fermentation.

Food Spoilage

  • Spoilage involves food becoming unsuitable for consumption.
  • Microorganisms in food use food nutrients for growth.
  • Decomposition and deterioration are important aspects of spoilage.
  • Food industry seeks to extend food shelf life for economic reasons.

How Microorganisms Cause Food Deterioration

  • Microorganisms utilize food nutrients.
  • These processes involve synthesis of new compounds.
  • Examples include food spoilage and the production of grape alcohol or other compounds.
  • Enzymatic changes and product breakdown lead to off-flavors

Food Safety

  • Diseases related to food are called foodborne illnesses
  • Examples include Salmonellosis (Salmonella bacteria), Campylobacteriosis (Campylobacter bacteria) and Escherichia coli (E. coli) infections.

Fermentation

  • Microorganisms can positively influence food.
  • Examples include cheesemaking using Penicillium roqueforti mold to produce blue cheese.

Importance of Microorganisms in Food

  • Good (desirable): Food bioprocessing, food preservation, and probiotics
  • Bad (undesirable): Foodborne diseases and food spoilage

Good (Desirable) Food Bioprocessing

  • Food bioprocessing uses biological processes employing microorganisms to produce various fermented foods.
  • These include starter cultures using raw materials from animal and plant sources.
  • Starter cultures are concentrated preparations of live cells added to the material for rapid fermentation initiation.

Food Biopreservation

  • Food biopreservation uses antimicrobial metabolites from certain microorganisms to control spoilage and/or pathogenic microorganisms in food.
  • Lactic acid bacteria (LAB) are commonly used since they result in useful antimicrobials such as lactic and acetic acids, and hydrogen peroxide

Probiotics

  • Probiotics are beneficial live bacteria cells taken orally.
  • They are used to promote and improve bodily health.
  • Examples include Lactobacillus acidophilus and bifidus bacteria in milk, yogurt using Lactobacillus bulgaricus and Streptococcus thermophilus, and lactobacillus and in cheese

Sources of Microorganisms

  • Microorganisms are found across diverse environments: brines, cold ponds, hot springs, air, soil, water, plants, and animals.

Atmosphere Microorganisms

  • Airborne microorganisms like bacteria (e.g., Bacillus, Streptococcus) and fungi (e.g. Penicillium, Aspergillus) are found in the air and can spoil food.
  • Fungi produce spores that are resistant to environmental damage, such as desiccation and light.

Soil Microorganisms

  • Soil is a source of microorganisms, including bacteria (e.g., Bacillus, Clostridium) and fungi.
  • These microorganisms can degrade complex organic materials.
  • Soil conditions such as acidity, pH, moisture, and temperature affect microbial growth and presence.

Water Microorganisms

  • Water can host various microorganisms like bacteria from the Enterobacteriaceae family (e.g., Escherichia coli, Staphylococcus, and Vibrio)
  • Many water-borne microorganisms are adapted to specific water conditions and can spoil foods

Plant Microorganisms

  • Microorganisms exist on plant surfaces and in the roots (e.g., Rhizoplane).
  • Examples include Cladosporium (black yeast), Aureobasidium, bacteria (Pectobacterium, Erwinia, Pseudomonas, and Xanthomonas).
  • Certain microorganisms can be responsible for food spoilage.
  • Microorganisms can influence food production, such as in fermented vegetables.

Animal Origin Microorganisms

  • Skin and internal linings (e.g. the nose and throat) harbor a diverse array microorganisms.
  • Skin organisms are normally Gram-positive bacteria like Staphylococcus, Corynebacterium, Propionibacterium.
  • Several strains can cause harm.

Conclusion

  • Most foods contain naturally present microorganisms.
  • Ensuring food safety and storage requires preventing microbial growth or destroying existing microorganisms
  • Environmental and nutritional factors are important influences on microbial growth and survival

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Description

Explore the role of microorganisms in food safety, spoilage, and the transformation of food properties. This quiz covers various bacteria, their effects on food, and foodborne illnesses that arise from contamination. Test your knowledge of the crucial relationship between microbiology and food quality.

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