Transcript Food safety

Dr. Nadia Aziz
C.A.B.C.M
Baghdad medical college
objectives
 Describe types of food born diseases and its causes
 Describe types of food preservation
 Define global warming
 Explain different ways of medical wastes disposal
Food safety
 The objectives of food processing and preparation are
to provide safe and neutrious food to the consumer.
 The responsibilities for accomplishing this objective lie
with every step in the food chain beginning with food
production in the farm and continuing through
processing, storage, distribution cell and consumption.
Food born diseases
1- Bacterial infection
 Salmonellosis: many people are permanent often
asymptomatic carriers. Chicken infected with salmonella
species can excrete these organisms into the eggs.
 Shigellosis: Salads are frequently implicated.
 Viberiosis: consumption of raw or undercooked shellfish.
 E coli: Enterotoxigenic strains are a notable cause of
traveler diarrhea
Food born diseases
2-viral infection
 Infectious hepatitis: control is achieved by cooking
food, stressing personal hygiene and by avoiding
shellfish harvested from polluted waters
 Enteroviruses: (coxsackie, echo ,Norwalk, rotavirus)
foods associated with transmission of viral agents are
raw shellfish , vegetables , fruits and salads
Food born diseases
3-Parasites
 Nematodes (round warm): Ascaris lumbricoides ,
Enterobius vermicularis
 Protozoa cause a large number of food born and
water born outbreaks each year. Entamoeba
histolytica, toxoplasma gondii, giardia lamblia cause
dysentery like illness that can be fatal.
Food born diseases
Bacterial Intoxication
 Staph. aureus :certain strain produce a heat - stable
enterotoxin, 25% of healthy people are carriers
 bacillus cereus: heat stable & heat labile
enterotoxins
 Ch. botulinum: infant botulism is the common form
of botulism(6 week- 6 month)
Food born diseases
chemical intoxications
 chemical hazards are minimally important as etiological
agents of food born disease .
 most human made chemicals associated with food born
disease find their way into foods by non intentional means
accidental or inadvertent contamination with heavy metals,
detergents or sanitizers can occur .
Food Preservation
 Preventing growth or activity of microbes with low
temperatures, drying, anaerobic conditions, or
preservatives can be done.
 Killing or injuring microbes with heat, irradiation, or
some preservatives is certainly effective.
Food Preservation
Steps to manipulate the microbial growth:
a. Avoid addition of actively growing organisms
that found on unclean containers, equipment, and
utensils & by reducing contamination.
b. Create unfavorable environmental conditions
for growth.
Food Preservation
Unfavorable environmental conditions for
growth :
Is the most important step of food
preservation & done by extremes of
temperature , irradiation, low Ph, and by
adding inhibitors and preservatives
Food Preservation
Asepsis:
 Packaging is the most widely used form of
asepsis and includes wraps packages, cans,
etc.
Food Preservation
 Modified atmosphere conditions:
 altering the atmosphere surrounding the food
can be a useful way to control microbes
examples: packaging with vacuum , CO2 , N2 , or
combinations of inert gases with or without
oxygen .
Food Preservation
 High temperature preservation :
 Based on destroying microbes, but may injure certain
thermoduric microbes (spore formers usually survive)
 Less severe heat processing is pasteurization which
usually involves heating at less than 100oC .
Food Preservation
 Low temperature preservation :
 Refrigeration freezing temperature should be
maintained as low as possible for
refrigerated food.
Food Preservation
 Drying:
 Foods can be preserved by removing or binding
water. any treatment that lowers water activity can
reduce or eliminate growth of micro organisms .
Food Preservation
 Preservatives :
 Inorganic preservatives examples are NaCl , nitrate,
nitrite , sulfite and SO2 .
 NaCl lowers water activity and causes plasmolysis by with
drawing water from cells.
 Nitrite and nitrates are curing agents for meats to inhibit
C.potulinum under vacuum packaging conditions
Food Preservation
Inorganic preservatives
sulfur dioxide (SO2) sulfite (so3) bisulfite HSO3
and metabisulfites S2O5 form sulfurous acids
which is the anti microbial agents
Food Preservation
Inorganic preservatives
• Nitrite can react with secondary and tertiary amines to
form potentially carcinogenic nitrosamine during cooking.
• Nitrates in high concentrations can results in red blood
cell functional impairment.
• Sulfating agents likewise can cause adverse respiratory
effects to susceptible consumer particularly asthmatics
Food Preservation
Irradiation: non ionizing radiation
 ultraviolet
 microwave
 infrared
Food Preservation
 ultraviolet are used to disinfect water, surfaces,
utensils walls ceilings and floors.
 ultraviolet will not penetrate opaque materials and
is good only for surface decontamination.
 infrared has little penetrating power
 microwaves have excellent penetrating power
Food Preservation
Fermentation:
 A number of foods use beneficial microorganisms in
the course of their processing.
 The sugar in certain food is converted to organic acids,
ethanol, or carbon dioxide, these three by- products
not only serve as desirable flavors but also provide a
significant antimicrobial barrier to pathogens.
Global warming
 Earth mantle of atmosphere acts like a greenhouse,
allowing passage of short-wavelength solar radiation
into the biosphere, trapping longer wavelength infrared
radiation.
 Without the greenhouse effect, earth surface
temperature would swing from over
500c in strong sunlight to -400c at dawn.
Global warming
 The concentration of greenhouse gases in the
troposphere has risen rapidly since the beginning of the
industrial era because several of these gases, notably
carbon dioxide, are products of fossil fuel combustion
and other human activities.
Global warming
 Over 6 billion metric tons of CO2, the principle
greenhouse gas, are added to the troposphere annually,
increasing amounts every year.
 Tropical rain forest , the most important carbon sink(a
biological system that absorbs carbon emissions, helping
to balance negative impacts on earth temperature), are
being rapidly depleted often by burning and adds more
carbon gases to the greenhouse.
Global warming
 Phytoplankton, another important carbon sink, are
damaged by increased ultraviolet radiation (UVR) flux
from depleting stratosphere ozone.
 It is estimated by global climate models that the
average temperature will rise by about 0.50C in the first
half of the twenty-first century.
Global warming
 Global warming has direct and indirect adverse effect
on health.
 heat –wave deaths are dramatic and obvious.
 increase incidence and prevalence of water born and
vector born disease. Malaria, is expected to be
prevalent in temperate zones and in altitudes in
tropical and subtropical regions from which it is now
absent .
Global warming
 The indirect effects of global warming include:
 A rise in sea –level of up to 50 cm by the year 2050, due
to melting of polar and alpine ice-caps and thermal
expansion of sea water mass. This will disrupt many
coastal ecosystems and perhaps some ocean fisheries.
 Anomalous weather emergencies such as catastrophic
floods, hurricanes and tornadoes and heat waves.
Global warming
 Stratospheric Ozone attenuation
 The chlorofluorocarbons (CFCS), a widely used class of
chemicals, would permeate the upper atmosphere
where they would break down under the influence of
solar radiation to produce Chlorine monoxide.
 Chlorine monoxide destroys Ozone, each molecule of
chlorine monoxide is capable of destroying over 10,000
ozone molecules.
Global warming
 Other atmospheric contaminant that destroy
stratospheric ozone include other halocarbons and
perhaps oxides of nitrogen (in exhaust emissions of
high- flying supersonic jet aircraft).
 Volcanic eruptions sometimes release Chlorine
compounds into the atmosphere, so natural as well as
human –induced processes can contribute stratospheric
ozone attenuation.
Global warming
 In 1985, Farman and coworkers observed extensive
attenuation (a hall) in the stratospheric ozone layer over
Antarctica during the southern hemisphere spring.
Seasonal ozone depletion has been observed in the
northern hemisphere too.
 Stratospheric ozone depletion was correlated with
increased surface level UVR flux.
 Ozone depletion is about 3-4% of total stratospheric
ozone and increasing annually.
Global warming
 CFCs were widely used as solvents in manufacture of
microprocessors for computers, foaming agents in
polystyrene packing, and as Freon gas in air conditioners
and refrigerators, their supposed chemical inertness
made them a popular choice.
Global warming
 Stratospheric ozone depletion permits greater
amount of harmful UVR to enter biosphere, where it
has adverse effects on many biological systems and
on human health.
Global warming
 The principal biological effects of increased UVR are
disruption of the reproductive capacity and vitality of
small and single- celled organisms , notably
phytoplankton.
 Increased UVR also has direct adverse effects on human
health, it increases the risk of skin cancer, increases the
risk of ocular cataracts, and probably impairs immune
function.
Medical Waste Disposal
The primary methods of treatment and disposal of
medical waste are:
 Incineration
 Autoclaves
 Chemical Disinfection
 Microwave
 Irradiation
Medical Waste Disposal
 Autoclaves
 Autoclaves are closed chambers that apply both
heat and pressure, and sometimes steam
 Chemical Disinfection
 primarily through the use of Chlorine products
Medical Waste Disposal
 Microwave
 The microwaves internally heat the waste, rather than
applying heat externally, as in an autoclave.
 Irradiation
 Through exposure of the waste to a cobalt source. The
gamma radiation generated by the cobalt source
inactivates all microbes that may be present in the
waste
Thank you