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How is F calculated?
F = Dr
- Dr = D at 121oC
- a = initial population
- b = final population
Name some processing aids
- Gamma Rays
- Cold Pasteurization
- PEF (Pulsed Electric Field technology)
- HHP (High Hydrostatic Pressure)
What are the 3 forms of radiation processes?
Radurization: low dose, quality enhancement, like pasteurization, reduction of spoilage organisms
Radicidation: equivalent to pasteurization, reduction of pathogens
Radappatization: equivalent to sterilization, high dose, medical equipment
What are the applications of chemical preservatives?
- - Minimize health risk
- - Improve nutritional quality
- - Enhance storage quality
- - Improve sensory properties
What is pKa?
Amount of undissociated acid
What prevents ropiness and mold in baked goods?
What is the active form of nitrates and what is the pKa of it?
How do nitrates work?
- Converted to nitrite
- Cell proteins react with nitrite to form iron-nitric oxide complexes
- Destruction of iron-sulfur enzymes
- Growth inhibited
What is the risk of using nitrates?
Nitrite + free amino group = potential carcinogen
What is the "natural" version of nitrites?
Cultured celery extract
Why are sulfites not permitted in meat?
Destroys vitamin B1
What are the properties of class I bacteriocins?
- Small, heat stable peptides
- Extensive post-translational modifications
- Unusual AAs (lanthionine)
- Ribosomally synthesized
What are the properties of class II bacteriocins?
- Small, heat stable, hydrophobic peptides
- Limited post-translational modifications
What are the properties of class III bacteriocins?
Large, hydrophilic proteins
What are the properties of class IV bacteriocins?
Bacteriocin synthesis MUST haves?
- Structural gene(s)
- Immunity gene
Bacteriocin MAY haves? (not always required)
- Transport genes
- Modification genes
- Regulation genes
What is an example of a Class I bacteriocin and how does it work?
- Affects cell membrane = pores
- Inhibits C. botulinum outgrowth
- Reduces canning process & heating time
What is an example of a Class II bacteriocin and what does it fight?
- Listeria monocytogenes
What is the "natural" version of Miocin?
Cultured corn syrup
What are some properties of LAB?
- Ferment carbs to lactic acid
- Gram (+), non-sporulating, nonmotile
- Grow anywhere with right pH and carbs
What are the 2 types of fermentation of lactobacilli?
- Homofermentative (obligate)
- Heterofermentative (obligate and facultative)
What 2 spp. are involved in yogurt?
- Lactobacillus delbrueckii subsp. bulgaricus- strong proteolytic activity, provides AAs for Staph
- Staphylococcus thermophiles- limited proteolytic activity, provides flavour
What are the products of Propionibacterium shermanii?
Propionic acid, CO2, acetic acid
Nutty flavour, holes in Swiss cheese
What are the 4 aspects of Starter Culture?
- Rapid fermentation of lactose
- Proteinase activity
- Phage resistance
- Production of inhibitory compounds
What are the 3 stages of yeast fermentation?
- Conversion of biomass to fermentable sugars
- Recovery of alcohol & product formation
What are the 3 different kinds of potable ethanol?
- Unfortified: beers, wines
- Fortified: ports, sherry
- Distilled spirits: whiskey, gin, vodka, rum
What is the bacteria in Hops?
- Humulus lupulusFlavour & preservation
What is malt?
Germinated barley, activates amylases
What are the 3 things involved in labeling guidelines?
- Identification of strain (latin name/strain ID)
- Quantitative declaration (CFU/serving)
- Ingredient list (common name/bacterial culture)
What are the safety considerations for ProB's?
- Antibiotic resistance
- Production of antibiotics
- Pathogenic potential
- Metabolic activities (D-lactate production, bile salt deconjugase activity)
BILE SALT DECONJUGASE, IT HAUNTS ME
What should PreB's be able to do?
- Resist gastric activity, hydrolysis
- Ferment by intestinal microflora
- Stimulate growth/activity of selected intestinal bacteria (ProB's and "good" microflora)
What are the health benefits of ProB's and PreB's?
- Normalized intestinal microbiota
- Stimulate immune system
- Metabolic effects (eg. lactose hydrolysis)
What are 2 types of monitoring of cleaning/sanitation?
- Microbial counts: next day results, more accurate
- Bioluminescence: same day results, measures ATP, less accurate
What are general features of Viral foodbourne illness?
- Few particles needed
- Shed in stools of infected individuals
- Need living cells to replicate
- Stable outside of host/acid-resistant
Symptoms of Norovirus
- Projectile vomiting, abrupt onset of non-bloody diarrhea, abdominal cramps, headaches, etc.
- Resolves within 24-48 hrs (24 hr flu)
Symptoms of Hepatitis A
- Jaundice, fever, nausea, anorexia, malaise, dark urine, abdominal discomfort.
- Lasts less than 2 months
Symptoms of Rotavirus
- Vomiting, non-bloody diarrhea (watery, explosive), fever, dehydration, electrolyte imbalance
- Affects mostly children
How are viruses controlled in food?
- Prevent contamination
- Thermal processes
- Sanitation (hand sanitizers don't count)
What parasites were talked about?
- Giardia lamblia
- Cryptosporidium parvumCyclospora cayetanensisToxoplasma gondiiTrichinella spiralis
What are the properties of Giardia lamblia?
- Livestock & foodborne (poor hygiene)
- Highly contagious
- 1 cyst dose
- Asymptomatic carriers
- Diarrhea 1-2 wks
What are the properties of Cryptosporidium parvum?
- Contaminated drinking water
- Raw/undercooked food contaminated with oocysts
- Onset 5-21 d
- Severe diarrhea, cramps, headache, nausea, vomiting (fever, coughing)
- Long exposure in immunocompromised = death
- MUNICIPAL WATER
What are the properties of Cyclospora cayetanensis?
- Transmitted through water, food, person
- Onset 2-11 d
- 1 cyst dose?
- Sever diarrhea
- Sometimes weight loss, bloating, stomach cramps, nausea, vomiting, etc.
What are the main points about Toxoplasma gondii?
- Obligate intracellular parasite
- From cat feces (only known host)
- Severe illness in fetus'
What are the properties of Trichinella spiralis?
- Undercooked pork/wild game
- 1 larvae dose
- Freeze to control
- 1-2 d nausea, diarrhea, vomiting, fatigue, fever, discomfort
- 2-8 wk headaches, fever, chills, cough, eye swelling, muscle pain, constipation, diarrhea, etc.