Transcript FOOD ALLERGY

Lecture Material - Food Safety
Inneke Hantoro
FOOD ALLERGY
What is food allergy?
• Food allergy is an abnormal response to a food
triggered by the body’s immune system.
• The symptoms of an allergic reaction are caused by
biologically active chemicals produced by the immune
system in its attempt to protect the body from a foreign
invader.
• Allergic reactions to food can cause serious illness or
even death.
• Food allergy is different with food intolerance although
both can show similar symptoms.
Types of food allergy
• IgE-mediated food allergy (immediate hypersensitivity)
– e.g. peanut allergy, cows’ milk allergy
• Cell-mediated food allergy (delayed hypersensitivity)
– involving sensitized immune cells in the small
intestine, usually lymphocytes, that are sensitized to
the specific substance that triggers the reaction 
inflammation on certain sites, symptoms appearing
24 hours or more after ingestion
– e.g. celiac disease
How do allergic reactions work?
An immediate allergic reaction involves two actions of
our immune system:
1.
Our immune system produces immunoglobullin E
(IgE) – a type of protein that works against a
specific food – antibody.
2.
IgE attaches basophils (white blood cells) and to
mast cells – cells found in all body tissues. The
typical sites of allergic reactions include nose,
throat, lungs, skin and GI tract.
How do allergic reactions work?
• Food allergens are proteins within the food that
enter our bloodstream after the food is digested.
• Food allergen go to target organs such as skin,
nose, etc and cause allergic reactions.
• An allergic reaction to food can take place within
few minutes to an hour.
How do allergic reactions work?
• The symptoms of cell-mediated allergic reactions do not
begin to appear until 6–24 hrs after ingestion of the
offending food. These reactions develop slowly, reaching
a peak at approx. 48 hrs and subsiding after 72–96 hrs.
• The mechanisms of cell-mediated food allergies are not
nearly as well understood.
• They involve an interaction between specific food
allergens and sensitized T lymphocytes - a major
component of the gut-associated lymphoid tissue.
Lymphocyte stimulation initiates the release of cytokines
and lymphokines which produces a localized
inflammatory response.
• Antibodies are not involved in these reactions.
Celiac disease
• Celiac disease, or gluten-sensitive enteropathy,
is a malabsorption syndrome occurring in
sensitive individuals upon the consumption of
wheat, rye, barley, triticale, spelt, and kamut.
• The consumption of wheat or other offending
grains or products made from these grains elicits
inflammatory damage to the absorptive epithelial
cells in the small intestine.
Celiac disease
• The loss of absorptive function along with the
ongoing inflammatory process results in a severe
malabsorption syndrome characterized by diarrhea,
bloating, weight loss, anemia, bone pain, chronic
fatigue, weakness, muscle cramps, and, in children,
failure to gain weight and growth retardation.
• The inflammatory mechanism involved in celiac
disease is mediated by intestinal T lymphocytes.
The allergic symptoms
• Itching in mouth as we start to eat the food.
• GI symptoms such as vomiting, diarrhea or
abdominal pain after the food is digested in
stomach.
• When the food allergens enter and travel through
the bloodstream, they may cause the blood
pressure to drop.
• As the allergens reach the skin, they can cause
hives or eczema.
• When the allergen reach the lungs, they may cause
asthma.
Cross - Reactivity
• If we have a life-threatening reaction to a certain
food, our body will show how to avoid similar
foods that might trigger this reaction.
• For example: if someone has a history of allergy
to shrimp, he/she will also show allergic
reactions to crab, lobster and crayfish.
Cross contact allergen
• Cross contact allergens occur when a residue or
other trace amount of an allergenic substance is
unintentionally added into a food not intended to
contain that allergenic substance and where
such occurrences are sporadic.
Common Food Allergies
• In adults:
Shellfish, peanuts, tree nuts (walnuts), fish,
eggs, wheat, soy.
• In children:
Eggs, milk, peanuts, soy.
Tree nuts and peanuts can cause deadly food
allergy reactions called anaphylaxis!
• Anaphylactic reaction is a severe reaction of rapid onset
that involves most organ systems (multiple organ failure)
and that results in circulatory collapse and a drop in
blood pressure.
• The 1st symptoms usually are burning, itching, irritation
of the lips, the inside of the mouth and the throat.
• Followed by nausea, vomiting, abdominal pain, and
diarrhea.
Food Allergen
• The allergenic moiety of the food is usually a protein.
• Allergenic proteins are usually not denatured under food
processing conditions and relatively resistant to
digestion.
• Other foods can produce allergen as well, but not as
often, e.g. strawberries.
• The foods to which adults or children usually react are
those foods they eat often, e.g.:
 Soy and rice allergy in Japan
 Codfish allergy in Scandinavia
 Peanuts allergy in US
Types of Food Allergens
• Milk proteins: caseins, whey proteins (betalactoglobulin), serum proteins (albumin).
• Egg proteins: ovalbumin, conalbumin (ovotransferrin)
and ovomucoid (heat stable).
• Grain proteins: gliadins, glutenins, albumins and
globulins.
• Peanuts  the most frequently cited causes of life
threatening anaphylactic reactions!
• Soy bean
• Seafood
• etc
Food Allergy Tests
• Skin tests
Identifying the type of IgE that is fixed to the skin mast
cell. For example: scratch test.
• Blood tests  analyze blood or blood serum
RAST (radioallergosorbent test) or ELIZA ( enzymelinked immunosorbent assay).
These tests measure the presence of
food-specific IgE in blood and
the total IgE level in blood.
Food Intolerance
• Food intolerance is more common than food
allergy, but it doesn’t relate to the immune
system.
• Food intolerance is caused by the lack of our
body’s ability to digest certain substances.
• Some people may have a food intolerance that
has a psychological trigger.
Types of Food Intolerance
• Food poisoning: foods contaminated with
microbes, such as bacteria and bacterial
products (e.g. toxins).
• Histamine toxicity
A reaction like an allergic reaction when people
consume histamine containing foods, such as in
cheese, some wines, tuna and mackerel.
Types of Food Intolerance
• Lactose intolerance
 It caused by lactase deficiency.
 Lactase is an enzyme that is in the lining of the gut.
 Lactase breaks down lactose, a sugar found in milk
and most milk products.
 Lactose is used by bacteria to form gas which causes
bloating, abdominal pain and diarrhea.
 At least one out of ten people suffer lactose
intolerance.
Types of Food Intolerance
• Food additives, such as:
 MSG, when it is taken in large amounts can
cause some of the following signs: flushing,
sensation of warmth, headache, chest
discomfort and feeling of detachment.
 Sulfites, in high concentrations can pose
problem for people with severe asthma.
How to treat food allergy?
• Avoiding to eat foods which can trigger allergic reaction.
• Exercised- induced food allergy
The allergic symptoms may appear as exercise
increases and body temperature rises. Therefore, it is
required to avoid eating for a couple of hours before
exercising.
• Taking medicine such as antihistamines to relieve GI
symptoms, hives, sneezing and runny nose or taking
bronchodilators to relieve asthma symptoms.
Consumer Protections & Labeling
• Food manufacturers are generally responsible about
posting alerts concerning allergen contamination and
recalling their products.
• Labeling of foods containing allergens have to be clear
and consistent.
• The application of GMP in food manufacturing to avoid
cross-contamination of food products by foreign
allergens.
• The awareness of the consumers in checking the labels.
Labeling
• The general labeling recommendations are:
– all allergen information should be grouped
together to be easily identified and not hidden
amongst other labeling information
– product description and representation should
provide an accurate expectation of the product
and should not be misleading
Labeling
– The print size should be big enough to be
easily read, preferably at a minimum 1.5mm
with sans serif font, and the font colour should
contrast distinctly from the background. The
use of lower or upper case will depend on the
overall presentation of labeling information.
(FSZAN)
Labeling
• A consistent approach in the presentation of
allergen information will help allergic consumers
more quickly and easily identify foods of concern,
helping to minimize accidental consumption of
unsuitable foods.
• The recommended format consists of:
– an ingredient list declaring in bold allergenic
substances and their derivatives; and
– an allergen summary statement; and
– a precautionary statement.
Labeling
References
• Food Allergy: An Overview. 2004. U.S. Department of
Health and Human Services. Retrieved from
www.niaid.nih.gov.
• Joneja, J. V.1998. Dietary Management of Food
Allergens and Intolerances: A Comprehensive Guide 2nd
Edition.J. A. Hall Publications LTD. Vancouver.