Metal contamination

C0NTAMINATION OF FOOD BY METALS

P.KUGANATHBFST 2102

• Food contamination : “The presence in food of harmful chemicals and microorganisms which can cause consumer illness”.

• not been intentionally added to food.

• Contaminants foods

1.various stages of its production& Packaging 2. From the environment

• Negative impact on the quality of food

CONTAMINATION

METALS IN FOOD• Around 80 of the 103 elements listed in the periodic table

are metals. • How to differentiate between metallic and non-metallic

elements by their physical characteristics

• The presence of the metals have both good and bad effects

Metallic Non metallic

typically solids may be gases, liquids

electrically conducting non-conducting

lustrous Not lustrous

Malleable & ductile Almost not like that

• There can be considerable variations in the concentration of metals even with in the same class of food, depending on its topographical origins and other factors.

• Metals may not be distributed evenly within a single sample of a food.

• Milling affects the metals concentration• Eg:. A whole grain of wheat can contain 7.4µg

copper/g ,but with only 2.0µg/g of this is in endosperm

• We consume only a small number of metals. These are a believed to essential for normal life.• Insufficient intake of any one of these essential

inorganic nutrients

Specific biochemical lesions with cells of the body

Development of characteristic clinical symptoms

Nutrients and other metals

Toxic metals eg: Cd,Pb,Hg

Nutrient metals

Micro nutrients

e.g: Cr ,Cu, Mo Macro nutrients

e.g: Ca ,Mg,

Na, K

Non toxic ,non essential

eg : Al,Sn

THE TOXIC METALS

• Not always possible to make toxic ability• Play essential roles in human metabolism and

body functional• Single metal difficult to consider toxicity • If the metals are consumed together, they are

capable of interacting with other metals and give toxicity.

• Eg:Toxicity of cadmium , are closely related to the amount of zinc present

• Traces metals can cause quality changes in foods during cooking and storage

• changes in food by metal contamination.• Eg:1. Fe + Anthocyanin black pigment in certain fruit

2. Iron affect the sensory qualities of liquid foods and loss of odor , bitter tastes 3. Traces metals oxidation of unsaturated fatty acids

EFFECT OF THE METALS IN THE FOOD QUALITY

HEAVY METALS IN THE FOODS

• The term heavy metal is - high specific gravity -have a strong attraction to biological tissues -have slowly eliminated from biological systemEg: Pb,Hg,Se,Cd,As

Pb

• Concentrations of lead in different food products vary greatly

• Lead in food creates mainly from atmospheric deposition and adherence of lead-rich soil particles to plants

• The content of lead plant foodstuffs > animal foodstuffs

As• The consumption of As by humans reflects

the quantities of seafood in the diet.• occurs mainly in the organic form

Hg• The toxicity of mercury -elemental, inorganic

and organic in form• more dangerous organic form> inorganic form or elements

• Inorganic and organic are found in food.

• Main source of the mercury -fish and other aquatic animals

• Mostly affected by Hg -pregnant and breast feeding women

• How metals get into food Metals Food

1. Industrial contamination(during the processing , packaging ,catering operation) 2. Up take metals by the plant 3. Food fortification 4. Geophagia

METALS IN FOOD AND THE LOW • The legislation is the rule of law that keeps a

country going smoothly and provides for law and orders it’s abused at times

• Codex Aliment Arius Commission of FAO/WHO

publish

The food safety act and each countries nutrient labeling and education act

THE ACCEPTABLE LEVEL OF CADMIUM IN VARIOUS FOODS

Food cadmium levels(mg/kg)

Chocolate and cocoa products

0.5

Kidney (cattle,sheep,pig) 2.5

Liver (cattle,sheep,pig) 1.25

Meat (cattle,sheep,pig) 0.05

Molluscs 2.0

Peanuts 0.1

Rice 0.1

Vegetable(leafy) 0.1

Vegetable(root and tuber) 0.1

THE ACCEPTABLE LEVEL OF LEAD IN VARIOUS FOODS

Food lead levels(mg/kg)

Brassicas 0.3

Cereals ,pulses ,legumes 0.2

Offal (cattle ,sheep ,pig poultry ) 0.5

Fish 0.5

Fruit 0.1

Infant formula 0.02

Meat (cattle ,sheep,pig,poultry) 0.1

Molluscs 2.0

Vegetables (other) 0.1

METAL ANALYSIS OF FOOD

sampling

Collect the data

Presentation of data

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