Env Health

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    ENVIRONMENTALHEALTH

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    introduction

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    Man Environmental relationship

    Disease vectors

    Food Water and waste water

    Air

    Solid waste

    Housing

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    DEFINITION E H is concerned with those forms oflife, substances, forces, and

    conditions in the surrounding of manthat may exert an influence on manshealth and well being.

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    MAN-ENVIRONMENTALRELATIONSHIP

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    The enviromental system

    MANSACTIVITIES

    ENVIORONMETAL

    HAZARDS

    LIFESUPPORT

    REDUCES ANDWASTES

    Air, Water,Food, Shelter

    Solids, Liquid,Gases

    Home, Work,

    Recreation,Transpotation

    Biological,Chemical,Physical,Psychological,

    Sociological

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    Environmental hazardsBIOLOGICAL :

    CHEMICAL :

    PHYSICAL :

    PSYCHOLOGICAL : SOCIOLOGICAL :

    Animal, Insect,Microbiological

    Poison and toxin,Allergens,Irritations,

    Vibration,Radiation, Forcesand Abrasion,Humidity

    Stress,Boredom,Anxiety,Discomfort,Depression

    Overcrowding,Isolation

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    PRINCIPLES OF CONTROL OFENVIRONMENTAL HAZARDS

    ISOLATION

    SUBSTITUTION

    SHIELDING

    TREATMENT

    PREVENTION

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    Isolation

    Isolation protect man from epidemicsbefore the rise of cities and the

    mobility populations.

    Natural waters remote from humanhabitation may be safe to drinkbecause no source of disease

    organisms exists.

    Populations remote from mosquitobreeding area are not subject to

    mosquito borne disease

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    Substitution

    Substitution is frequently a low cost,easily applied, completely effective

    method of environmental control.

    A simple application is the substitutionof a harmless cleaning fluid for a toxic

    one.

    The substitution of degradabledetergents for non degradabledetergents.

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    Shielding

    Shielding is the use of barriers forprotection while a person remains in

    relatively close proximity to the

    hazard.Safety glasses and protective clothingare personnel measures which may be

    employed

    Screening for the exclusion of themosquitoes and flies and heat shields

    are other example.

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    Treatment

    Environmental treatment methods,which may be used in conjunction withdilution or dispersion of contaminating

    substances or prophylaxis, include (1)destruction, (2) conversion, (3)

    removal, and (4) inhibition.

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    Treatment(1)Complete destruction is applicable

    particularly to biological hazards.Boiling and cooking employ heat to kill

    microorganisms.

    Autoclaving employs heat andpressure.

    Microorganisms may also be killed byoxidation using chlorine or a similar

    substance.

    Other chemicals are used asdisinfectants, algacides, fungicides,bactericides, pesticides, larvicides,

    rodenticides, etc

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    Treatment

    (2) Conversion of harmful substancesto less harmful usually involves

    chemical or biochemical processes.

    Strongly acid and strongly alkalineliquid wastes may be mixed together

    in a way to neutralize each other.

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    Treatment

    (3) Removal of harmful substancesfrom water and air may be

    accomplished by a variety of

    methods.Sedimentation and filtration result in

    the removal of solid particle.

    Chemicals may causes coagulation andprecipitation for removal of solublesubstances and as aids to

    sedimentation.

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    Treatment

    (4) Inhibition may be used where anenvironmental threats exist, but itseffects may not materialize or may

    be minimized by environmentalintervention.

    pH controls or the addition of salt orsugar may be used in food

    preservation.

    Refrigeration may inhibit the growthof bacteria and the production of

    toxins.

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    Preventive

    Minimizing exposure throughrestriction of activities,

    immunization against disease and

    the use of prophylactic agents mayavoid infections and, as such, aremeasures which may be used to

    avoid the effects of environmental

    hazards.

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    Disease vectors

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    Mosquito Flies

    Cockroaches Spiders Ticks

    Bedbug Rodents

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    vector The term vector is used to denote acarrier of disease organisms. Thevector may purely mechanical, as inthe case the housefly in the spreadof enteric organisms, or biological, inwhich instance the disease organism

    multiples or undergoes change thevector, as in the case of developmentof malaria parasites in anophelinemoscquitoes.

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    Mosquito Mosquito are small, fragile, two wingedinsects that belong to the family Culicidae.

    Their distribution worldwide, and several

    hundred different species of mosquitohave been described. They are not only very annoying pest, but

    are known carriers of human and animaldiseases.

    Mosquitoes pass through four stages intheir development; egg, larva, pupa, andadult.

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    Mosquito Some mosquitoes feed on mammalianand other animal hosts, while others

    feed on fruits and plant nectars. Onlythe female mosquito has mouthpartsdevelop for bloodsucking andtherefore is the known or suspectedvector of a number of humandiseases, including malaria, yellowfever, dengue, and encephalitis.

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    Mosquito surveillance Mosquito population surveys areconducted to determine the species,

    abundance, and seasonal variations. The information gathered from these

    surveys maybe used to guide control

    operation. Whether adult, larvae, andegg surveys are made is dependentupon the purposes of the survey.

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    Mosquito surveillance Adult mosquitoes may be collected innatural or artificial resting places,

    various collection devices or in bitingcollection.

    Mosquito larvae surveys are

    conducted to determine the extentof mosquito breeding and to helpguide mosquito control efforts.

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    Flies Flies belong to order Dipteria andcharacterized by one pair of wings. Theyundergo complete metamorphosis: egg,larva, pupa, and adult.

    Domistic flies have been incriminated ascarriers of typhoid fever, enteric disease,

    parasitic worms. Biting flies can carrydisease such as tularemia, and anthrax. Flylarva may invade tissues and causes acondition known as myasis.

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    Cockroaches Cockroaches are insects belonging tothe family Blattidae. Their life cycle

    consist of three distinct stages: egg,nymph, and adult.

    Cockroaches can serve as mechanical

    carriers of diarrhea, dysentery,typhoid, and polio virus.

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    Spiders Spiders are not considered diseasevectors, because they do not actually

    carry pathogens. Bite from spiders can cause illness

    and, some cases, death due to the

    venom.

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    Ticks Ticks and mites are oval parasitesthat belong to the order Acarina.

    Tick carry a number of diseaseorganisms, such as Rocky Mountainspotted fever, Colorado tick fever,

    tick relapsing fever, and Tularemia.

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    Bedbugs Bedbugs, cimex lectularis, are true insectsand have a cosmopolitan distribution. Thelife cycle consists of the egg, nymph, andadult stages.

    Bedbugs hide in cracks and crevices duringthe day and usually feed at night.

    The bedbugs is a severe nuisance and someindividuals are sensitive to their bites.

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    Rodents

    There are three species of domesticrodent are considered to be of publichealth importance:

    Rattus norvegia (Norway rat) Rattus rattus (Roof rat) Mus musculus (House rat)

    They serve as reservoirs of severalimportant human diseases such asleptospirosis, salmonellosis, and ratbitefever.

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    Rodents

    They are also hosts for the fleas andmites that are vectors of plaque,

    rickettsiapox, and murine typhus. They also cause considerable

    economic loss and damage by

    destroying and contaminatingfoodstuffs and other materials.

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    Rodents

    Surveillance 1. determine the species andpopulation densities of domestic rats

    2. determine the frequency ofoccurance or rat infestations, ratharborages, and food sources,

    3. develop an appropriate rat controlprogram in accordance with thesefindings.

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    Rodents

    control An effective rodent control should beconducted on a communitywide basis,judicious use of rodenticides, citicizenparticipation, make environmental lessattractive to rats, demolition ofsubstandard housing, rebuilding storm andsanitary sewers, improving garbagestorage, collection, and disposal; daily

    cleaning animal shelter, removal of rodentharborage. Rodent control has to coordinated through

    several community agencies and mustresult in a change in citizens attitude

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    Food

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    Man needs food as a source of energyfor performing work and as source or

    raw material with which carry out theprocesses of procreation and tissuebuilding, that he is able to survive,grow, and propagate.

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    Food preservation 1. Moisture-Solids balance 2. Controlled Microbial Action

    (Fermentation)

    3. Chemical addition 4. High temperature treatment 5. Low temperature treatment 6. Freeze drying

    7. Ionizing radiation

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    Food preservation 1. Moisture-Solids balance: dehydration,sugaring, and salting.

    2. Controlled Microbial Action

    (Fermentation): Foods are inoculated withmicroorganisms for purpose of producing aparticular food product and to prevent itsspoilage.

    3. Chemical addition : a foreign chemicaladded to the food during processing,smoking, curing and pickling, preservativesantioxidants, moisture control, ph control,physiological control agents.

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    Food preservation 4. High temperature treatment: foodpreservation for canning.

    5. Low temperature treatment: food

    preservation for freezing raw material. 6. Freeze drying: the drying of substance

    from the frozen state. 7. Ionizing radiation : were economy in

    operation.

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    Nutrient Losses in Food

    handling, processing, storage Most food contain their maximumnatural content of nutrientingredient at the point of harvest.The longer the period of time fromthis point and the more severe ofhandling, thermal treatment, and

    processing, the greater the tendencyfor the nutrient content to decrease.

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    Nutrient Losses in Food

    handling, processing, storage In heat processed for canning, 75-90%retention for vit A, E, folic acid, niacin,pyridoxin, and ribobflavin; 35% withthiamin.

    In cooking process, B1 losses in beans andcarrots 25%, nearly 90% is lost after 1hour.

    In protein product such as roast beef,

    lamb, and fish; vit B1, B2 losses araoud40%

    Long storage; tend to be detrimental tonutrient content.

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    Toxic effects of

    microbial action in food Stapylococcus Clostridium botolinum

    Aspergillus Salmonella

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    Toxic effects of

    microbial action in food Stapylococcus :cause of a large percentageof food intoxication, 75-90% to allreported food poisoning outbreaks.

    Clostridium botolinum: requires low-acid,anaerobic condition, can produce toxin attemperature as low as 380F. By the time

    symptoms appear, treatment is difficult.CFR is 60-80%.

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    Toxic effects of

    microbial action in food Aspergillus : peanuts are known to becomecontaminated by aspergilli, there is apossibly that it might be a problem for

    man (aflatoxin). Salmonella : has been isolated from meats,

    baked goods, milk and milk products,

    vegetables, dry coconut, cocoa, and others.

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    Spoilage Problems Microbial contamination in freshfood

    Microbial contamination in preservedand prepared food

    Helminth contamination

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    Spoilage Problems Microbial contamination in fresh food :Fish live at relatively low temperaturesand therefore contain potent enzymesystems. Fresh fish have a brightirridescent coating, very little slime, deepbright red gills, and bright eyes with blackpupils and highly transparent cornea.Spoiled fish loses its irridescent

    appearance, has a thick slime coating, agreyish brown gills, and shows sunken eyeswith opaque cornea. Its odor turns to aputretactive (H2S) type.

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    Spoilage Problems Microbial contamination in preservedand prepared food : can stem fromimproper storage temperature forfood containing viable vegetablesmicroorganisms, from failure ofpackaging material to protect

    products from environmentalcontamination.

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    Spoilage Problems Helminth contamination : thepresence of higher parasitic forms as

    infestations capable of transfer toman, can be a serious food problemof public health. The more commonworms are tapeworms (cestodes) androudworms (nematodes).

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    Nonmicrobial Food toxins Plant poisons Seafood poisons

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    Plant poisons: goitrogens, estrogens,lathyrus, hemagglutinins, hydrogen

    cynide, antivitamins and antienzymes,cholinestrase inhibitors, flavorings,gossypol.

    Seafood poisons: major problem inJapan. More common toxic fish arepuffers, the mucus and flesh of some

    lampreys, moray eel flesh.

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    Food additives Intentional additives Incidential additives

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    Intentional additives:Nutritional supplements (vitamin A, D,

    amino acids, and mineral Fe, Mg);Color modification ( to make food,sausages, more attractive and must beedible, safe, and appropriately tested);

    Flavoring compounds (the major use ofchemical additive in food, sodium chlorideand sugar are natural agent, methylanthranilate (grape) or benzaldehyde

    (cherry) are synthetic).

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    Incidential additives:Processing aids, often chemical

    agent such as chelating agents areused to avoid the problem of metalion interference with food nutrient

    and color.Sulfur dioxide, is used to fumigatedried fruit and to act an antienzymefactors. SO2 tends to destroy the Bcomplex vitamins.

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    Sanitary consideration in

    food handling Premises maintenance Plant location, construction, and

    equipment design Food services operations

    P i i t th

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    Premises maintenance:the assuranceof a safe whole some food supplybegins with general appearance andhousekeeping around the foodestablishment. Neat, well orderedgrounds, clean uncluttered exteriors,

    clean floors, walls, and windows,adequate washrooms, well maintainedeating facilities and offices- allfacilities the importance placed on

    sanatation by the management.

    Pl t l ti t ti d

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    Plant location, construction, andequipment design: the location andconstruction of food processingfacilities should minimize thepossibility of environmentalcontamination. Generally,

    construction and lighting should besuch as to permit easy inspection andcleanability, and to prevent theaccumulation or introduction of

    undesirable contaminants.

    F d i ti i

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    Food services operations: use iscatering commissaries, cafeteria,

    vending machine, or restaurants,generally requires regulation underone or more codes.

    Usually this plans must show layout,arrangement, and constructionmaterial of food preparation areas,plus any alteration or addition tothese areas before any work begun.

    P d h

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    Waste Production in the

    Food Processing Industry Stockyard wastes Barnyard wastes

    Fishery wastes Dairy wastes

    Fruit and vegetables wastes

    Fermentation wastes Processing plant wastes