Handout B

    Cards (63)

    • Approaches to Shelf Life Determination
      • Direct shelf life determination and monitoring
      • Accelerated shelf life estimation
    • Spoilage of Food Products
      • Meat products
      • Seafoods
      • Dairy products
      • Egg
      • Vegetable and Fruit Products
      • Cereals, flour, and bakery products
    • Bakery Products
      • Commercially produced bread – Molds
      • Homemade breads – Ropiness (e.g. B. subtilis)
      • Cakes – Molds
    • Accelerated Shelf Life Estimation
      • Performed to meet product launch dates
      • Storage temperature is raised to increase the ageing process
    • Challenge Tests
      • Samples are incubated under conditions that reproduce the large-scale food production and storage period
      • May be inoculated with specified target organisms of interest (e.g. Clostridium sporogenes)
    • Indicator Organisms
      • Provide indirect evidence concerning a particular feature in the past history of the sample
      • e.g. fecal contamination or inadequate heat treatment
      • Index organism – Indicated the possible presence of an ecologically similar pathogen
      • Often employed to assess food safety and hygiene than quality
    • Module 3: Spoilage- and Disease-Causing Microorganisms
      • Spoilage Mechanisms of Different Food Products
      • Causative Agents of Diseases and Associated Food Vectors
    • Microbiological Determination of Shelf Life
      • Storage trials
      • Challenge tests
      • Predictive modelling
    • Direct Shelf Life Determination and Monitoring
      • Applicable for products with short shelf lives
      • Batches of samples to be taken at specified stages in the development of the product
      • Samples are stored under controlled conditions until their quality becomes unacceptable
      • Tested for smell, texture, flavor, color, and viscosity
    • Shelf Life is the time between the production of the product and the point at which the product becomes unacceptable to the consumer
    • Cereals and Flour
      • High in proteins and carbohydrates
      • Low aw restricts growth of all microorganisms if stored properly
      • e.g. Bacillus and molds
    • Chemical Indicators of Spoilage
      • Depletion of glucose (e.g. red meat)
      • Production of gluconic and 2-oxogluconic acid (e.g. beef)
      • Production of L- and D-lactic acids, acetic acid, and ethanol (e.g. pork and beef)
      • Biologically active amines (e.g. Tyramine in vacuum packed beef)
      • Volatile compounds (e.g. Proponol in beef)
    • Storage Trials
      • Samples are taken at timed intervals and analyzed for: Total microbial load, Specific spoilage organisms (e.g. Pseudomonads, LAB), Viable counts are compared with sensory evaluation of the product
    • Predictive Modelling
      • Simultaneously predict the growth of microorganisms over a range of conditions
      • Validate the model using published and in-house laboratory data
    • Causative Agents of Diseases and Associated Food Vectors
      • Indicator Organisms
      • Foodborne pathogens and agents
    • Characteristics of a Food Safety Indicator
      • Easily and rapidly detectable
      • Easily distinguishable from other members of the food flora
      • Have a history of constant association with the pathogen whose presence it is to indicate
      • Always present when the pathogen of concern is present
      • Density correlates with the pathogen of concern
      • Growth requirements and growth rate are equal
    • Enterobacteriaceae
      • Gram-negative bacilli and facultative anaerobes
      • Includes Escherichia, Salmonella, Shigella, Yersinia, and Enterobacter
      • Indicators of enteric pathogens
    • Common Indicator Organisms
      • Coliforms
      • Enterobacteriaceae
      • Enterococci
      • Bacteriophages
    • Campylobacter
      • Gram-negative
      • Sporadic and self-limiting gastroenteritis
      • Includes C. jejuni (80% of cases) and C. coli (15%)
      • Found in raw chicken, beef, milk, mushrooms, clams, hamburger, water, cheese, pork, shellfish, eggs, cake icing
    • Bacteriophages
      • Indicator of waterborne viruses
      • Present in human fecal matter
      • Plaque enumeration using agar overlay technique with a tester bacterial strain
    • E. coli
      • Gram-negative
      • Includes Enteropathogenic E. coli (EPEC) causing diarrhea in infants
      • Enterotoxigenic E. coli (ETEC) causing "Traveler’s diarrhea"
      • Enteroinvasive E. coli (EIEC) causing Shigellosis-like symptoms
      • Shiga toxin-producing E. coli (STEC) causing hemorrhagic colitis and hemolytic uremic syndrome
      • O157:H7 strain is of major concern, found in ground beef, poultry, apple cider, raw milk, vegetables, cantaloupe, hot dogs, mayonnaise, salad bar items
    • Foodborne Pathogens and Agents
      • Bacteria
      • Viruses
      • Parasites
      • Toxins
      • Prions
    • Shigella
      • Gram-negative
      • Causes Shigellosis with bloody/non-bloody diarrhea
      • Found in salads, raw vegetables, bakery products, sandwich fillings, milk, dairy products, poultry
    • Salmonella
      • Gram-negative
      • Causes gastroenteritis, enteric fever, and invasive systemic disease
      • Found in raw poultry, meat, eggs, milk and dairy products, vegetables, fruits, chocolate, coconut, peanuts, fish, shellfish
    • Coliforms
      • Gram-negative, rod-shaped facultatively anaerobic bacteria
      • Fermentation of lactose to acid and gas within 48 hours at 45°C
      • Indicator of: Fecal contamination, Enteric pathogens, Post-processing contamination
      • Includes Escherichia, Klebsiella, Enterobacter, and Citrobacter
      • E. coli is the best indicator of fecal contamination
    • Characteristics of a Food Safety Indicator
      • Density correlates with the pathogen of concern
      • Growth requirements and growth rate are equal to that of the pathogen
      • Persists slightly longer than the pathogen of concern (Die-off rate parallels that of the pathogen)
      • Absent from foods that are free of the pathogen (Except at certain minimum numbers)
    • Enterococci
      • Indicator of fecal contamination in water
      • E. faecalis from human feces, E. faecium from human and animal feces
      • Indicator of hygienic quality for frozen, dried, and heat-treated food
      • Die more slowly than E. coli, more resistant to drying than coliforms
      • May survive better than pathogens so detection may have little consequence
    • Foods associated with concern
      • Ground beef, poultry, apple cider, raw milk, vegetables, cantaloupe, hot dogs, mayonnaise, salad bar items
    • Types of Shigella
      • S. sonnei, S. flexneri, S. dysenteriae, S. boydii
    • Types of Vibrio
      • V. cholerae, V. parahaemolyticus, V. vulnificus
    • Brucella causes Brucellosis which includes symptoms like sweating, headache, lack of appetite, fatigue, and fever
    • Shigella causes Shigellosis which can lead to bloody/non-bloody diarrhea
    • Types of Brucella
      • B. abortus (cattle), B. suis (swine)
    • Food sources of Cronobacter
      • Powdered infant formula, plant-based ingredients, vegetables and salads
    • Type of Plesiomonas
      • P. shigelloides
    • Listeria monocytogenes causes Listeriosis which includes meningitis and sepsis
    • Aeromonas causes Gastroenteritis and is found in seafood, snails, and drinking water
    • Vibrio is gram negative
    • Plesiomonas is gram negative
    • Flaccid Paralysis is a neurological condition characterized by weakness or paralysis, reduced muscle tone or hypotonia
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