Midterm 1 Flashcards
How do microorganisms get into our food?
contamination when growing, processing, when another animal consumes it, in water, in soil, in animal feed
What are the 5 microorganisms found in food?
bacteria yeasts molds viruses parasites
Characteristics of bacteria
chemoheterotrophs
fastidious
growth can be restricted by pH, aw, and type of packaging
Growth rates determine
how fast food will spoil
how fast food will ferment
Generation time
time required for a population of bacteria to double
Gram Stains
Tell us about bacteria by telling us about the cell wall
gram pos - thick layer peptoglycan, no outer cell wall (more susceptible to antimicrobials)
gram neg - thin layer peptoglycan, have an outer cell wall
Characteristics of yeasts
nonfilamentous, unicellular fungi
used in food fermentation
reproduce by binary fission and budding
Characteristics of mold
filamentous
grow over range of temperature and moisture
can cause disease and be toxic to humans
used in food fermentations and antibiotics
important cause of food spoilage
Characteristics of viruses
have genetic material (dan/rna)
need a host**
don’t grow in foods**
Characteristics of Parasites
undesireable microorganisms in food
cause illness - settle into parts of the body
need a host**
don’t grow in foods**
can be controlled by - cooking to 70 degrees celsius internally, and sometimes by freezing
Protazoa
other types of parasites
have cysts/oocysts that survive outside of a host - makes them very stable
How do lipids spoil?
they go rancid
oxidative - peroxides (chemical)
hydrolytic - ffa’s
may get an odor change
How do proteins spoil?
proteolysis (degredation)
- ammines, ammonia, H2S
“rotton egg smell”
i.e. when meat turns green - hemoglobin degredation
How do carbohydrates spoil?
fermentation
organic acids - souring
Regulations for perishable foods
if storage life is less than 90 days
packaged - must have BBD
retail - must have “packaged on date”
What does a BBD tell you?
Tells you how long the quality of the product will stay consistent until
a food could still be safe after it’s bbd
Predictive food micro total counts tell us what?
how many organism but not which organisms
no indication of food safety
may indicate spoilage if you know the history of the food
changes is numbers in a processing plant may signify that something has gone wrong
psychrotrophic
organism that survives/thrives in cold environments (less than 20 degrees)
mesophilic
organism that grows best at moderate temperatures (20-45 degrees)
Pour plate vs spread plate
pour plate - 1 ml of sample into dish, add medium
spread plate - 0.1 ml of sample onto agar and spread
Plating vs. enrichment
plating - estimate of number of cells/g or ml in a food
- can use selective agar to differentiate
enrichment - selective broth
- allows for growth of a specific
- presence or absence ONLY**
- often used for detection of pathogens
Sequence of events for food borne disease
- organism must contaminate food
- one of the following
a) organism/toxin must survive processing and storage
b) organism must be able to multiple (MAYBE - sometimes just being there is enough) - sufficient quantities must be ingested (to survive the natural protection processes of the stomach)
Adulterant
illegal to sell a product with the specific organism in it
Most typical place where food is mishandled
food service
The shift from mainly animals causing disease to plants is due to:
more fresh vegetables being consumed (rather than canned/boiled etc) because we are more health conscious
vegetable are imported from all over the world
The most common factor in food handling associated with food borne disease is
Temperature/time abuse:
- too much time b/w preparation and consumption
- improper cooling
- inadequate reheating
- inadequately cooked food
Who is responsible for food safety?
Government producers processors retailers distributors consimers
Canada’s food inspection system
Provincial - local farming and food products made and sold in alberta (alberta health services, agriculture and forestry)
Federal - anything that goes beyond provincial borders (CFIA - deal with recalls, grants HACCP recognition status, shift from reactive to proactive system)
Benefits of implementing HACCP
- maximize product safety
- improve product quality (as soon as you are controlling safety you are controlling quality**)
- increased customer confidence and demand
- improve operational efficiency and profitability (less reworks and waste)
- market access and international trade etc,
- legal liability (useful in defense of “due diligence”
The cost of poor safety or quality (1-10-100 rule)
For every $1 spent on prevention, the plant saves $10 on correction costs and $100 on product failure costs
ISO 9000 Quality System
a quality management system aimed primarily at preventing any non-conforming product during production and distribution.
- write what you do, do what you write, prove it, improve it (bottom line for any HACCP plan)
Making a business case for HACCP
Build a business case
- do cost/benefit analysis, consider 1-10-100 rule
Quantify
- current product waste/loss
- rework
- cost of handling returns, testing, recalled products
General info on HACCP
Hazard analysis critical control point
- identifies specific hazards and installs preventative measures
- mandatory in canada
now often required for trade - assurance of safety is NOT from end testing
Why is end testing not effective?
low prevalence and uneven distribution of hazards
- costly
- if procedures to reduce risk are sufficient, shouldn’t need to end test
FSEP
Food safety enhancement program
- developed to assist plants with developing and implementing HACCP
- includes HACCP plans and pre requisite programs
HACCP vs. Prerequisite programs
Pre req’s - practices/procedures carried out to favour production of safe food
- covers many “indirect” hazards
- prior to and post HACCP
- SOP’s and GMP’s
HACCP - about the food - identification of critical control points
Critical Control Points
Points in the process where you can control hazards
Pre requisite program examples
Premises (building, employee facilities, water supply)
Transportation/purchasing/receiving/shipping and storage (if testing food temp -CCP, if testing temp of truck/storage - pre req)
Equipment (working properly)
Personnel (training and hygiene)
Sanitation and Pest control
Recalls
Allergen Control
Pre req programs must
- be monitored (who is doing what, how often, how are they doing it)
- outline deviation procedures (what to do when things go wrong)
Foodborne intoxications general definition
Toxin is produced during bacterial growth of the food, food is ingested, results in food borne ilness
Exo vs. endo foodborne intoxication
exo - toxin formed outside the cell
endo - formed in outer membrane of gram negative bacteria
Site of action of toxins in food intoxication
entero - effects GI, usually diarrhea, non inflammatory, NO blood
cyto - damages specific cells, damages tissue, dysentery, blood cells (you get blood b/c tissue damage)
neuro - affects nerves, blocks or fake nerve impulses
Clostridium perfringens
Produces the toxin once in the gut** (only one)
Aerotolerant anaerobe (does not like o2 but spores may still survive in it) (ex. will survive in a glaze)
Doesn’t like to grow in presence of others (if been on antibiotics microbiota killed, easier to grow)
Produces: gas (i.e if bubbling but cold), heat resistant spores, many toxins (enterotoxin - increases fluid to GI tract, watery diarrhea)
5 types - A important for intoxication
Growth - very fast (GT 6-7 min), mesophile** (37-45 optimum) won’t grow in fridge
short onset, 12-24 h duration (body is just getting rid of toxin, not the organism itself)
Large numbers (10^6) infective dose
Cells survive passage to small intestine where they sporulate (dormant form of organism)
Source - ubiquitous (enviro, animal intestine)
Risk foods - high protein foods, cooked meats, soups
Control - time/temp (hold >60), proper cooling,
Clostridium botulinum
STRICT anaerobe
Produces: some gas, spores, potent NEUROtoxin (blocks transmission of nerves to muscle)
Blocks Acetylcholine - flaccid paralysis
Infant botulism: immature gut microbiota/adults w/ wounded microbiota (honey has spores)
Wound botulism: a spore in a wound that has healed over (no 02) - mainly drug users
Key characteristics: 8 toxins, 5 groups (mainly worry about groups 1 and 2)
Symptoms: 12-36 h, nausea, vomiting, diarrhea, constipation
serious - may get blurry vision, speech impairment, paralysis and death
- can get into diapraghm muscle and prevent you from breathing (but we have an antitoxin - needs to be given early “botox”), slow recovery for this
source: streams, soil, intestine of animals
risk foods: fish, meat, f&v, honey*
control: freezing, proper heat treatment (pressure cooking), pH, nitrite, NOT heating
outbreaks: often where the native population lives - they treat their fish differently, 1 case is considered an outbreak with botulism
Type I vs Type II Clostridium Botulinum
type 1 - potent toxin, does not grow at refrigeration temp, more heat resistant spores, PROTEOLYTIC -signs of spoilage if organism grows - will stop people from eating, produces gas more
type 2 - WILL grow at refrigeration temp, NONPROTEOLYTIC - no signs of obvious spoilage
Temperature to kill spores
110-120 degrees celcius AND pressure (i.e. pressure cooker)
D value
time at 100 degrees that it takes to decrease the number of organisms by 1 log
Bacillus cereus
rod shaped facultative anaerobes (can grow with or without 02)
spore forming, motile
Key characteristics: 2 type of toxins (emetic aka vomiting and diarrheal), toxin produced during growth (if you control growth won’t get toxin)
source: ubiquitous, environment 15% of population have some of it
control: proper holding/refrigeration, prevent cross contamination, control growth
Emetic
- assoc with starchy foods, heat stable, resistant to proteolytic enzymes, spores highly heat resistant!
- 1-6 h onset, nausea and vomiting (not usually diarrhea)
- risk foods: meat, soup, veg
Diarrheal
- assoc w/ protein foods
heat labile (toxin produced after cooking), sensitive to proteolytic enzymes, high infective dose
- 8-15 h onset (longer onset b/c getting into lower GI tract), watery diarrhea and cramps
- risk foods: unrefrigerated cooked rice
Staphylococcus aureus
Facultative anaerobe, gram pos clumps, 30% of individuals (may not show)
characteristics: 5 enterotoxins, SEA most toxic/common, 10^5 infective dose, highly resistant to heat (survives boiling)** and enzyme degredation, does NOT grow at refrigeration temperatures, wide range of toxins, extremely low aw***, likes high salt
source: environment, human carriers (sneezing), cross contamination, food prep
Risk foods: high protein (esp. processed meat b/c high salt), high salt, creams/bakery products
symptoms: 2-4 h onset, flu symptoms
control: prevent contamination and growth
3 questions that HACCP answers
- What are the hazards associated with my product?
- ingredients/packaging material, process, people - Where do these hazards occur?
- How can I control or eliminate these to an acceptable level?
- a pre req or a process step
12 steps to developing a HACCP plan
- assemble team
- describe product and its intended use
- list product ingredients and incoming material
- construct a process flow diagram and plant schematic (shows where cross contamination may occur)
- verify these
- list hazards associated with each step and incoming material in plant’s process (hazard analysis)
- determine critical control points
- establish critical limits
- Monitoring
- Deviation procedures
- verification procedures
- record keeping
Hazard Analysis
Every ingredient and every step of a process is analyzed to determine what hazards are present - controlled, reduced, or eliminated
biological, chemical and physical hazards
Biological Hazards
pathogens, parasites, viruses, molds
Contamination - everything contaminates to be a hazard
Survival - an issue when we expect a decrease in numbers (i.e. cooking/antimicrobials) (freezing a survival issue with some parasites b/c can kill)
Growth - an issue during cooling and storage (bacteria and mold grow)
Critical Control Points
point in a process where you can reduce or eliminate a hazard
most common are: cooking, chilling, formulation control
Critical limit
one of more prescribed tolerances that must be met to ensure that a CCP effectively controls a hazard
ex. pH
Monitoring
A planned sequence of observation/measurements to ensure that critical limit maintains product safety
- who what when
ex. pasteurization operator checks every 15 min and records time and temp data
Deviation
failure to meet require critical limits defined for a CCP
- need to define corrective action
Verification
Methods/tests to determine if HACCP system is valid and doing what we expect it to do
ex. analytical testing, auditing, sampling etc.
Campylobacter spp.
Campylobacter jejuni - animals/birds (most common), and C. coli.- pigs
gastroenteritis
does not grow in food** contamination main issue
500 CFU dose
symptoms: 2-5 day onset, headache, maybe fever before GI symptoms, diarrhea WITH blood and mucus, sequel is Guillain Barre syndrome (facial paralysis)
risk foods: raw milk, water, poultry
control: cross contamination on farm and processing, pasteurization
Salmonella
S. enterica serovar Typhimurium most frequent disease (S. enteritidis taking over with eggs)
infective dose 10^5
Symptoms: 1-3 day onset
typhiod, fever, long lasting septicemia, bloody stools, nausea and vomiting, sequele is arthritis
Sources: pets, poultry, eggs, dairy, sprouts, melons, cucumber, turtles
Control: keep out of food supply, thermal processing
Yersinia enterocolita
Grows at refrigeration temperature** (milk cartons)
Symptoms: localized abdominal pain(lower right), GI symptoms
Source: ubiquitous, swine
Control: proper cooking and storage (not hard to kill, not resistant to heat
Enterohemorrhagic Escherichia coli (EHEC)
Shiga toxin producing (STEC)
has to be able to adhere to GI tract
infective dose EXTREMELY low
Enterotoxigenic E.coli (ETEC)
“travellers diarrhea”
2 toxins: LT and ST
very high infective dose 10^7
Symptoms: shorter onset, longer duration, rice water diarrhea, fever is RARE
Sources: water, brie cheese, deli foods
Control: hygiene, thermal processing
Enteroaggregative E. coli (EAEC)
cause of bloody diarrhea in many children
- in developing countries
Vibrionaceae (non halophilic)
Vibrio cholerae 01,0139
- high infective dose (not hard if comes from water)
- LT
- rice water diarrhea, sudden vomiting
- onset 1-3 days
- likes warm temp and higher pH
Vibrio cholerae Non 01, 0139
- milk gastroenteritis
- high infective dose
Vibrionaceae (halophilic)
Requires salt**
vibrio parahaemolyticus
- “japanese” phenomenon - eat more raw seafood
- facultative anaerobe
- has toxin that lysis RBC’s
- short onset, GI symptoms
control: avoid contamination, thermal processing
Listeria monocytogenes
High mortality rate because of who it infects
Infective dose could be very low
can cross a placenta and blood brain barrier***
can grow at refrigeration temperature
Sources: soil, dust, animal feed, animals
Foods: raw dairy, chicken, deli meat, canteloupe (tell you to stay away from these during pregnancy)
Control: avoid contamination, proper heat treatment
Shigella
very hard to differentiate between e coli
common in day cares
very LOW infective dose (10-100)
Produces shiga toxin**
Symptoms: bloody diarrhea with mucus, vomiting, FEVER (different than EHEC)
Source: not usually from food, usually from contaminated worker
