Chemical Food Preservation

Topics: Food preservation, Bacteria, Carboxylic acid Pages: 8 (1154 words) Published: April 28, 2013

Food Preservation Methods Food Preservation Using Chemicals


A naturally / synthetically produced substances that is added to food/beverages to prevent spoilage

Preservatives: The good, bad and ugly!



Sometimes, food may spoil because of the changes in the food itself.

When food spoils, the following may change: • appearance • taste • texture • odour © Food – a fact of life 2007

Food may become unsafe to eat.

Micro-organisms need certain conditions to grow – this is why food needs to be stored properly. Micro-organisms need: warmth food time

Time In the right conditions, food poisoning bacteria (micro-organisms) can double every 2 minutes.

© Food – a fact of life 2007

© Food – a fact of life 2007

We can slow these processes by preserving or processing foods!



Malaysian Food Law: Additives and Preservatives

Akta Makanan 1983 & Peraturan peraturan Makanan 1985
Aditif makanan:
bahan yang selamat dimakan yang ditambah dengan sengaja kepada makanan untuk mempengaruhi ciri-ciri makanan tersebut (kualiti, tekstur, konsistensi, rupabentuk luaran, odor, rasa, keasidan dsb.)

Akta Makanan 1983 & Peraturan peraturan Makanan 1985
Bahan pengawet:
Apa-apa bahan yang, apabila ditambah pada makanan, boleh menyekat, merencat atau menahan proses penguraian, penapaian, atau pengasidan makanan tersebut tetapi tidaklah termasuk herba, rempah, cuka atau asap kayu. Pg 274 Daftar I

Akta Makanan 1983 & Peraturan peraturan Makanan 1985
Bahan antipengoksida:
Apa-apa bahan yang, apabila ditambah pada makanan, boleh melambatkan atau merencat pengembangan ketengikan atau lain-lain kemerosotan dalam makanan disebabkan oleh pengoksidaan. Pg 285 Daftar II



Preservatives Classification

Natural Organic acids Citric Benzoic


Vitamin C

Antimicrobials Calcium propionate Sodium nitrite Disodium EDTA Sodium nitrate Sulfites








Organic Acids
Occur widely in nature Several are permitted to be used in foods including:

Acetic acid Citric acid

Sorbic acid Benzoic acid

Organic acids

Lactic acid Propionic acid



Acetic Acid
Most widely preservative employed as food

Lactic and Citric Acid
Less effective compared to acetic acid Bacteriostatic at pH Bacteriocidal at pH < 5.5 Not effective against fungi Mode of action not known but differs from acetic acid Probable effect lowering pH is through > 5.5;

Often present due to lactic acid bacteria fermentations Sufficient quantities (> 0.3%) of acid will kill not just inhibit eg. yeasts, molds, bacteria Antimicrobial effect is due to lowering the pH as well as the effect of the undissociated acid Salad dressings and mayonnaise

Lactic and Citric Acid (cont’d)
Although less effective both lactate and citrate are used as: • pH regulators in foods and washes. Eg. applied in meat carcass wash and meat products • Flavor enhancers

Lactic acid in Salami

Glucono Delta Lactone in Meat Products

Sorbic Benzoic Propionic Acids
Used to control spoilage in bread

• Natural constituents in many fermented foods (wine, honey, fruit juices, meat products) •‘Tangy flavour’ • Lowering pH – preserve the food from deteriotion of enzymes and microbes

• Typically used as anti-fungal agents



Sorbic Acid
• Sorbate is usually used as the calcium, sodium or potassium salt • Primarily effective against molds and yeast but also inhibits a wide range of bacteria • Has an LD50 of 10g/kg body weight which make it the safest preservative known! Also, enviromentally-friendly! (Generally used at concentrations of 0.025% to 0.10%) • Widely used in cheese and dairy products, baked goods, fruit juices

Benzoic Acid
• Found naturally in high levels in cranberries • Sodium benzoate is used to inhibit yeast and molds • Most inhibitory at a pH...
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