REHS Study Flashcards
Most important phase in bacterial growth
Lag Phase
Exponential growth of bacteria
Log Phase
Environmental conditions and food may become restrictive, causing leveling of bacterial growth
Stationary Phase
Bacteria start accumulating waste products and toxins that kill each other
Death phases
Bacteria Growth Factors
Food, Acidity, Time, Temperature, Oxygen, Moisture
Bacteria require nutrients such as proteins and carbohydrates to reproduce
Food
Most microorganisms grow best at this pH
4.6pH to 7.0pH
This pH is considered out of potentially hazardous zone
<4.6 pH
With the right conditions bacteria reproduce…
every 15 - 30 minutes
What is the temperature danger zone
41F - 135F
Bacteria grow in aerobic and anaerobic conditions
Oxygen
Bacteria require water to survive
Moisture
Oxidation reduction potential provides…
ideal environment for anaerobes
Sous vide means…
Excluding air from the product
Key role in controlling lag phase of bacterial growth
Temperature and Time
Maximum hot food cooling time limits are as follows:
From 135F to 70F within first 2 hours. From 70F to 41F or below within 4 hours.
Hot Food Preservation
Do not put cold food in steam table. Steam table is used to keep hot food hot (135F- 165F), not to cook foods or warm foods. Fridge foods should be reheated to at least 165F (w/in 2 hours) prior to putting in steam table.
What is the purpose of canning?
To destroy organisms and not provide environment for which they can grow. Damaged cans introduce air, activation aerobic bacterial activity
Sodium nitrate
Malicious food additive, used to meat prevents growth of botulism and retains quality of food
Methemoglobinanemia
Infant ingestion of sodium nitrates causes Blue Baby Syndrome
Monosodium Glutamate (MSG)
Food additive produced naturally by use of bacterial decomposition. Known as flavor enhancer and meat tenderizer
Generally Regarded as Safe (GRAS)
FDA requires testing to certify if element is safe. Ex: ketchup, pepper, salad oil, vinegar
Ethylene Diamine Tetra Acetate (EDTA)
Common additive to prevent botulism growth. Known to work better than nitrates, but unlike nitrates, does not stop oxidation of meat and color changes
Sulfurs (Sulfites)
Stops enzyme reaction in fruit/veggies, preserves food, prevents discoloration. Approved in manufacturing, must be labeled for use. Illegal to add in restaurants
Malachite Green
Can be used to detect addition of sulfites in food
Phosphoric Acid
Common in soft drink sodas to produce acidic reaction to enhance carbonation
Three categories for hamburger fat (%)
Regular Grade (no more than 30% fat)
Lean Grade (no more than 22% fat)
Extra Lean Grade (no more than 15% fat)
3 categories should not exceed 6-8% difference
Vending Machines
If vending machine holding temperature falls below minimum state required holding temp, then there is an automatic mechanism or switching device that locks the unit from further use until properly serviced
Food Illness Outbreak- CDC definition
- Two or more persons have the same disease, have similar clinical features or have the same pathogen
- A single case of suspect botulism
- A single case of mushroom poisoning
- A single case of ciguatera or paralytic shellfish poisoning or rare disease (Vibrio vulnificus)
Confirmed Case
Laboratory test conducted on the suspect bacteria or virus
Presumptive Case
Laboratory test showed negative on the suspect bacteria or virus
Suspect Case
No laboratory samples submitted
Secondary Case
Infected person was in contact with a primary case
Cal Code Definition AGI
Cal Code 113733- Acute gastrointestinal illness
a.) Diarrhea
b.) Vomiting in conjunction with diarrhea or two other gastrointestinal symptom such as fever or abdominal cramps
Foodborne Illness team consists of:
1.) Environmental Health
2.) Public Health Department
3.) Laboratory
What are the Seven Principles of the HACCP Plan?
1.) Conduct Hazard Analysis
2.) Identify Critical Control Points
3.) Establish Critical Limits
4.) Establishing Monitoring Procedures
5.) Establish Corrective Actions
6.) Establish Verification Procedures
7.) Record Keeping Procedure
Determine the Food Safety Hazardous and then identify the preventive measures that apply to control these hazards
Conduct Hazardous Analysis
Procedure in a food process (from its raw state through processing) at which control can be applied and as a result a food safety hazard can be prevented, eliminated, or reduced.
Identify Critical Control Points
Maximum or minimum value to which a physical, biological, or chemical hazard must be controlled at a critical control point to prevent, eliminate, or reduce it to an acceptable level
Establish Critical Limits
Procedure to monitor the control points
Establishing monitoring procedures
Are taken when monitoring indicates a deviation from a critical limit has not been met
Establish corrective actions
Ensures that the HACCP plan is adequate
Establish verification procedures
Written HACCP plan, records, documenting and monitoring of critical control points, critical limits
Record Keeping Procedures
Modern Sewer System
At most 2 days to reach plant. Travels at rate of at least 2ft/sec
Waste Water
Manholes placed 300-500 ft apart
Heaviest flow of sewage through wastewater treatment plan is between 3-9PM
Sanitary waste out of home, general business & institution from toilet, showers, sink, etc
Domestic Waste
Waste water discharged from manufacturing plant (restaurant, hospitals, canning, meat processors, refineries, etc)
Industrial Waste
Can infiltrate sewer system by cracks in sewer pipe
Ground Water
Certain amount of water infiltration from leaky pipes. High water table can be introduced into system by open drain
Storm Drain Runoff
Prohibiting draining of any type of wastewater onto public streets
National Pollution Discharge Elimination System
Liquid waste coming out of the ground at refuse landfills. Can be from rainfall seeping into landfill, or liquid waste intentionally dumped
Leachate
Fresh wastewater is 99.8% water and 0.2% solid concentration
Physical Characteristics of Waste Water
Fresh water water is also called..
Gray Water
Hot Zone at 113-158F
Thermophillic Zone
Medium Zone. Grows at 59-112F
Mesophillic Zone
Cold Zone. Grows at 35-50F
Psychrophillic Zone
Pipes drain liquid onto land
Surface Disposal
Shallow underground collection of pipes, title segmented loosely to allow water to percolate
Tile Field Disposal
Leach lines laid 2-5’ underground, perforated pipes (4” thick)
Subsurface Disposal
No longer accepted, Dispose of waste water into large water body, river, stream, etc
Dilution Disposal
Waste water being treated. Waste water going into a treatment plant
Effluent
Something that is taken into material
Absorption
Something that adheres to the material
Adsorption
Standard weight of one gallon of water
8.34 lbs
One cubic feet of water contains
7.48 gallons
Bar Screening (removes large objects), Grit Removal (sand/gravel), Pre-aeration (introduces oxygen, helps remove oil/scum), Flow Meter (measures rate of flow), Chlorine (optional)
Preliminary Treatment
Sedimentation (Clarification Tanks, removes solids that can settle, floating debris)
Primary Treatment
Collects raw sludge and relocates for sludge digestion, Bio/Chemical/Physical Treatment (Further removal of solids and dissolved solids of the waste water)
Secondary Treatment
Filtration (Filters to remove particles/color/odor), Disinfection (Destroys pathogenic bacteria), Used mainly for reclaimed water
Tertiary Treatment
Activated sludge, trickling filter, oxidation ponds, composting subsurface disposal field (Biological Treatment Process)
Aerobic Treatment Process
Sludge digestion, methane production, septic tanks, composting
Anaerobic Treatment Process
Holds volume of water for period of time at shallow depths (3-5’) to promote aerobic activity and purification water. Remains for 45-60 days before use.
Stabilization Pond (Lagoonization)
Solid portion of waste water
Sludge
Most biologically active, high potential to turn septic
Raw Sludge
Contains biological agents that digest sludge into inorganic materials, aka “Mixed Liquor”
Activated Sludge
Product of total anaerobic digestion, most stable
Digested Sludge
Simple hole dug, only used in past, now only used for emergencies
Pit Privy
Wastewater designed to seep into ground from _____ vault
Cesspool
If cannot connect to sewer, then next best option is ______. Water water retained in multi-compartment tank for ~24 hours where 60-70% of sludge settles.
Septic Tanks
What pipe color is reclaimed water?
Purple
What pipe color is steam, gas, oil?
Yellow
What pipe color is sewer?
Green
What pipe color is potable water?
Blue
What pipe color electrical?
Red
What pipe color are leach lines?
White
The concentration of a contaminant that, if exceeded, triggers treatment or other requirements that a water system must follow
Action Level (AL)
The highest level of a contaminant that is allowed in drinking water.
Maximum Contaminant Level (MCL)
Set as close to the public health goal or Maximum contaminant level goal as economically or technological feasible
Primary MCL
Set to protect the odor, taste, and appearance of drinking water
Secondary MCL
The level of a contaminant in drinking water, below which there is no known or expected health risk
MCL Goal
The level of disinfectant added for water treatment that may not be exceeded at the consumer’s tap
Maximum residual disinfectant level (MRDL)
The level of a disinfectant added for water treatment below, which there is no known or expected health risk.
Maximum residual disinfectant level goal (MRDLG)
The level of a contaminant in drinking water below, which there is no known or expected health risk.
Public Health Goal (PHG). Set by the California EPA
MCLs and MRDLs for contaminants that affect health along with their monitoring and reporting requirements, and water treatment requirements
Primary Drinking Water Standard (PDWS)
When was the Safe Drinking Water Act signed into law?
December 16, 1974
When was the Safe Drinking Water Act amended?
1986 & 1996
What did the Safe Drinking Water Act do?
- Set national standards regulating the levels of contamination in drinking water
- Require public water systems to monitor & report their levels of identified contaminants
- Establish uniform guidelines specifying acceptable treatment technologies
Federal & State Laws
- California Safe Drinking Water Act (SDWA)
- Bulletin 74-90 and 74-81
- Jurisdiction & authority of local construction standards
- Caused by polluting runoff (phosphate detergents, nitrate, fertilizers, sewage)
- Increase in nutrients cause algae blooms, algae, fish die and decompose to bottom creating oxygen loss, and new oxygen produced by living algae towards surface
Algae Blooms (Eutrophication)
Oligotrophic (Young), Mesotrophic (Middle-aged), Eutrophic (Old/Mature Lake)
Lake Age
Drinking Water Treatment
Untreated Water –> Coagulation –> Flocculation –> Sedimentation –> Filtration –> Disinfection –> Treated Water
- Chemical reaction that occurs when a coagulating chemical is added to water.
- Most common is aluminum sulfate (alum)
- Coagulant reacts with water & minerals in the water to form floc particles
- Neutralize negative charge on suspended particles - form larger clumps that are heavy enough to settle
Coagulation
- Process of slow, gentle mixing of the water to encourage tiny floc particles to clump together & grow to a size that will settle quickly
- Flocculent particles at 1.5 mm (1/16 inch) are usually heavy enough to settle within a few minutes
- Mechanical mixers (preferred) or hydraulic mixing
- Primary concern is the degree of mixing
Flocculation
- Process of holding the water in quiet, low-flow conditions so suspended matter & particles can be settled out by gravity to the bottom of the tank & removed as sludge
- Purpose is to remove as much of the flocculent & other suspended material as possible before water flows to the filters
- The final step in pretreatment prior to filtration
- An economic means of clarifying water
Sedimentation
- Variation of gravity filtration
- Uses biological processes as well as physical straining
- Simple, cost-effective
Slow Sand Filters
- Much greater water treatment filtration rate and the ability to clean automatically using back washing
- Complete filtration cycle (filtration and back washing) occurs sequentially
Rapid Sand Filter
_____ are a convenient and economical choice for applications that require gross particulate removal.
Particulates are trapped in the bag for quick disposal. ____ are available for low flow and come in welded styles. They have multiple micron removal efficiencies.
Bag Filter
_____ is a valuable water purification process when mineral-free water is the desired end product.
Most mineral constituents of water are physically larger than water molecules. Thus, they are trapped by the semi-permeable membrane and removed from drinking water when filtered through a reverse osmosis system. Such minerals include salt, lead, manganese, iron, and calcium. ____ will also remove some chemical components of drinking water, including the dangerous municipal additive fluoride.
Reverse Osmosis
The selective destruction or inactivation of pathogenic organisms
Disinfections
Disinfection types:
- Chlorine
- Ozone
- UV light
- Boiling
Chlorine in this form has the highest disinfecting ability
Free available residual chlorine
_______ process of adding chlorine to water until the chlorine demand has been satisfied
Breakpoint Chlorination
Zone of saturation of groundwater, easy to find in flat areas, hard in hills
Water Table
Well bored into aquifer that has enough pressure to bring water to surface without pump
Artesian Well
Aeration Zone, Saturation Zone, Impervious Rock, Aquifer Water
Ground levels
97% of world’s fresh water. Water percolates at 3ft/yr into aquifer
Aquifer
Caused by over drilling of aquifer, creating cone at top of well
Cone of Depression
When constructing, 3 things to consider (expense, depth of water table, type of construction)
Wells
Best type of quality, solid casing installed with perforation at bottom for aquifer. Large kinetic hammer drives casing into ground and past point of saturation. Well uses submergible pumps. Required 50’ well seals
Case Driven Well
Use earth augers, depth is limited to length of auger used
Bored Well
Manually dug by man, machine, finished well lined with concrete, bricks, tile or clay pipes. Not deep
Dug Well
Prevents contaminants from entering the well casing
Sanitary seal
Supports pumping equipment & aids in sealing against surface water
Well Slab
Metal tube placed in the well to keep the well open
Well Casing
Mixture of cement, water, and sometimes sand
Grout
Space between the drilled hole and the casing. Grout seals the well against contamination
Annulus
At the bottom of the casing, penetrating the aquifer. The screen provides enough open spacing for unrestricted water flow. Gravel packing aids in filtering & increases well efficiency.
Well Screen (intake screen) & Gravel Packing
Allow you to connect your water pipe from your water well pump to an under ground discharge, to go to your house.
Pitless Adaptor
When your well is constructed the hole in the ground is bigger than in the ground is bigger than the well casing
Faulty Annular Seal
