Food Safety: Spoilage and Preservation
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Which type of food is least likely to spoil quickly due to microbial growth?

  • Fresh vegetables
  • Sugar (correct)
  • Potatoes
  • Meats

    • What characteristic of food is NOT typically associated with its spoilage?

  • pH level
  • Nutrient content
  • Color (correct)
  • Moisture level

    • Which of the following statements about food spoilage microorganisms is accurate?

  • They can only grow at high temperatures.
  • They typically require high moisture foods.
  • They are psychrotolerant and can grow in refrigeration. (correct)
  • They thrive in non-perishable foods.

    • Which method is NOT commonly used for food preservation?

    <p>Increasing nutrient levels</p> Signup and view all the answers

    Which of the following foods is classified as semi-perishable?

    <p>Nuts</p> Signup and view all the answers

    Which factor does NOT directly affect the time required for microbial spoilage?

    <p>Type of packaging used</p> Signup and view all the answers

    Which category of food is most susceptible to microbial spoilage?

    <p>Fruits</p> Signup and view all the answers

    Food preservation strategies often do NOT include which of the following?

    <p>Increasing food temperature</p> Signup and view all the answers

    Which food preservation technique involves the removal of water through freeze drying?

    <p>Desiccation</p> Signup and view all the answers

    What is the primary benefit of fermentation in food preservation?

    <p>It creates a high level of organic acids or alcohol.</p> Signup and view all the answers

    Which bacteria are primarily involved in the production of organic acids in fermented foods?

    <p>Lactic acid bacteria</p> Signup and view all the answers

    In foodborne diseases, what distinguishes food poisoning from food infection?

    <p>Food infection requires sufficient quantities of viable pathogens.</p> Signup and view all the answers

    Which of the following fermentation processes involves the use of Saccharomyces cerevisiae?

    <p>Production of alcoholic beverages</p> Signup and view all the answers

    What type of chemical is often added to foods during preservation to inhibit microbial growth?

    <p>Antimicrobial chemicals</p> Signup and view all the answers

    High-pressure preservation, also known as pascalization, primarily aims to achieve what?

    <p>Reduce microbial load</p> Signup and view all the answers

    Which of the following correctly describes nonfermented pickles?

    <p>Cucumbers marinated in vinegar</p> Signup and view all the answers

    Which bacterium is primarily responsible for Staphylococcal food poisoning?

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

    What is the most common cause of foodborne illness?

    <p>norovirus</p> Signup and view all the answers

    Which factor does NOT lead to food poisoning?

    <p>Consuming pasteurized dairy</p> Signup and view all the answers

    What temperature should hot food be maintained above to prevent food poisoning?

    <p>63ºC</p> Signup and view all the answers

    What are common food sources of Clostridium perfringens?

    <p>Improperly heated gravy</p> Signup and view all the answers

    What is the typical onset time for symptoms of Staphylococcal food poisoning?

    <p>1 - 6 hours</p> Signup and view all the answers

    Which symptom is NOT typically associated with Clostridial food poisoning?

    <p>Severe vomiting</p> Signup and view all the answers

    What is the recommended treatment for Staphylococcal food poisoning?

    <p>Fluids and antinausea drugs</p> Signup and view all the answers

    What is the main source of botulinum toxin responsible for Clostridial food poisoning?

    <p>Inadequately processed canned foods.</p> Signup and view all the answers

    Which symptom is specifically associated with botulism caused by Clostridium botulinum?

    <p>Flaccid paralysis.</p> Signup and view all the answers

    What is the treatment approach for botulism if diagnosed early?

    <p>Administration of botulinum antitoxin.</p> Signup and view all the answers

    How does food infection differ from food poisoning?

    <p>Food infection arises from viable pathogens multiplying in the body.</p> Signup and view all the answers

    What type of food infection produces enterotoxins within the intestinal tract?

    <p>Enterotoxigenic type.</p> Signup and view all the answers

    Which organism is primarily responsible for salmonellosis?

    <p>Salmonella enterica.</p> Signup and view all the answers

    What is a recommended prevention measure to avoid botulism from canned foods?

    <p>Avoiding canned foods with bulging lids.</p> Signup and view all the answers

    Which potential source can contribute to salmonella contamination?

    <p>Raw meat and poultry.</p> Signup and view all the answers

    What antibiotic is commonly used to treat confirmed Campylobacter infections?

    <p>Azithromycin</p> Signup and view all the answers

    Which of the following is a common source of Listeria monocytogenes contamination?

    <p>Cook-chill foods</p> Signup and view all the answers

    What is a serious consequence of an infection caused by Yersinia enterocolitica?

    <p>Enteric fever</p> Signup and view all the answers

    During pregnancy, what severe outcome may Listeriosis potentially cause?

    <p>Stillbirth</p> Signup and view all the answers

    What method is NOT mentioned as a prevention strategy for Campylobacter infections?

    <p>Refrigerating leftovers</p> Signup and view all the answers

    What is a key characteristic of the bacterium Listeria monocytogenes?

    <p>It is acid-tolerant.</p> Signup and view all the answers

    Which treatment is appropriate for invasive listeriosis?

    <p>Intravenous penicillin</p> Signup and view all the answers

    What is the phylum classification of Listeria monocytogenes?

    <p>Firmicutes</p> Signup and view all the answers

    Study Notes

    Food Spoilage

    • Food spoilage is any change in food that makes it unacceptable to consume.
    • Food categories based on perishability:
      • Perishable: Fresh foods, e.g., meats, fruits, vegetables.
      • Semi-perishable: Potatoes, some apples, nuts.
      • Non-perishable: Sugar, flour, low moisture content, can be stored for long periods.
    • Spoilage is influenced by:
      • Moisture level.
      • Nutrient content.
      • Acidity or alkalinity.
    • Spoilage time depends on:
      • Initial inoculum size.
      • Growth rate during exponential phase.
    • Spoilage microorganisms are often psychrotolerant, meaning they can grow at refrigeration temperatures (3–5°C).

    Food Preservation

    • Food preservation methods aim to slow or stop microbial growth.
    • Major methods include:
      • Altering temperature, acidity, or moisture level.
      • Radiation or chemicals that prevent microbial growth.
    • Examples of techniques:
      • Canning, refrigeration, pasteurization.
      • Osmotic pressure (adding solutes like salt or sugar).
      • Desiccation (freeze drying).
      • Antimicrobial chemicals (nitrites, sulphites).
      • Aseptic packaging.
      • Radiation (disinfestation, sprout reduction, bacterial pathogen reduction).
      • High-pressure preservation (pascalization).

    Fermentation

    • Metabolic activities of microorganisms preserve many foods and beverages.
    • Fermentation process produces preservative chemicals.
    • Important bacterial groups:
      • Lactic acid bacteria (fermented milks).
      • Acetic acid bacteria (pickling).
      • Propionic acid bacteria (certain cheeses).
    • Yeast Saccharomyces cerevisiae produces alcohol for preservation in alcoholic beverages.

    Foodborne Diseases

    • Foodborne diseases are common source diseases, often due to improper food handling and preparation.
    • Two main categories:
      • Food poisoning (intoxication): Ingestion of pre-formed microbial toxins.
      • Food infection: Ingestion of viable pathogens that cause growth in the host.

    Factors Leading to Food Poisoning

    • Preparation of food too far in advance.
    • Inadequate thawing.
    • Consuming raw food.
    • Storage at ambient temperature.
    • Inadequate cooling.
    • Improper warm holding (below 63°C).
    • Inadequate reheating.
    • Undercooking.
    • Infected food handlers.
    • Contaminated processed food.
    • Poor hygiene.

    Staphylococcal Food Poisoning

    • Cause: Staphylococcus aureus, can grow aerobically or anaerobically, produces enterotoxins.
    • Sources: Humans (nose, mouth, skin), untreated milk, poultry, eggs.
    • Signs and symptoms: Vomiting, abdominal pain, diarrhoea, weakness, lower-than-normal temperature, onset within 1-6 hours.
    • Treatment: Rest, fluids, antinausea drugs.
    • Prevention: Proper sanitation and hygiene in food production, preparation, and storage.

    Clostridial Food Poisoning

    • Clostridium perfringens: Produces spores that release enterotoxins, often associated with improperly heated or reheated food.
    • Sources: Gravy, poultry, meats.
    • Signs and symptoms: Abdominal pain, diarrhoea, nausea, onset 12-18 hours.
    • Prevention: Proper heating (75°C) to destroy toxins, avoid cross-contamination between raw and cooked food.

    Botulism

    • Cause: Clostridium botulinum, produces neurotoxin.
    • Sources: Fish, meat, dust, soil, vegetables, inadequately processed canned foods, open wounds.
    • Signs and symptoms: Voice change, double vision, drooping eyelids, severe constipation, onset 12-36 hours, flaccid paralysis.
    • Prevention: Careful canning practices, avoid feeding honey/corn syrup to infants under 1 year, avoid bulging cans.
    • Treatment: Botulinum antitoxin.

    Food Infection

    • Microorganisms multiply in intestinal tracts and cause disease.
    • Types:
      • Enterotoxigenic: Microorganisms produce enterotoxin in the intestinal tract.
      • Invasive: Microorganisms invade through the intestinal tract.

    Salmonellosis

    • Cause: Salmonella enterica/Salmonella typhimurium, gram-negative bacterium.
    • Sources: Raw meat, poultry, eggs, flies, people, sewage, contaminated water.
    • Signs and symptoms: Fever, diarrhoea, abdominal cramps, nausea, vomiting.
    • Treatment: Rest, fluids, antibiotics in severe cases.
    • Prevention: Thorough cooking of meat and poultry, proper hygiene.

    Campylobacter

    • Cause: Campylobacter jejuni, gram-negative bacterium.
    • Sources: Raw poultry, unpasteurized milk, contaminated water.
    • Signs and symptoms: Diarrhoea, fever, abdominal cramps, nausea, vomiting.
    • Treatment: Antibiotics (azithromycin), hospitalization for severe dehydration.
    • Prevention: Thorough cooking of poultry, proper hygiene, washing of uncooked poultry and kitchenware.

    Listeriosis

    • Cause: Listeria monocytogenes, gram-positive bacterium, acid-, salt-, and cold-tolerant.
    • Sources: Unpasteurized milk and dairy products, cook-chill foods, meat, poultry, salad vegetables.
    • Signs and symptoms: Mild flu-like illness to meningitis, septicaemia, pneumonia, onset 1-70 days.
    • Treatment: Intravenous antibiotics (penicillin, ampicillin, trimethoprim plus sulfamethoxazole).
    • Prevention: Pasteurization, proper food handling, decontamination of equipment, avoiding high-risk foods during pregnancy.

    Other Foodborne Infectious Diseases

    • Yersinia enterocolitica: Enteric bacterium found in domestic animals, contaminates meat and dairy products.
    • Signs and symptoms: Diarrhoea, abdominal cramps, fever, potentially enteric fever (typhoid fever, life-threatening).
    • Prevention: Thorough cooking of meat and poultry, proper hygiene.

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    University of Guyana BIO 2107 Lecture 4: Microbes and the Food Industry PDF

    Description

    Explore the critical concepts of food spoilage and preservation in this quiz. Learn about the categories of perishable items, factors affecting spoilage, and various preservation techniques. Test your knowledge on how to keep food safe and extend its shelf life.

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