Control by Antimicrobial Preservatives and Bacteriophages ◾ 497
Lactoperoxidase
Lactoperoxidase is an enzyme (glycoprotein) and is naturally present in raw milk, colostrum, saliva,
and tears. The antimicrobial activity of lactoperoxidase is mediated by oxidizing thiocyanate (SCN−)
present in milk in the presence of hydrogen peroxide (H 2 O 2 ) to form hypothiocyanate (OSCN−) and
hypothiocyanous acid (HOSCN). Both OSCN− and HOSCN have antimicrobial activity against
pathogens, including Staphylococcus aureus, Lis. monocytogenes, Esc. coli O157:H7, Salmonella, and
Yersinia enterocolitica in food products such as beef, vegetable juices, milk, and liquid whole egg.
Ovotransferrin
Ovotransferrin, also known as conalbumin, is a glycoprotein present in egg whites, which also
possesses antimicrobial activity. It is a metalloprotease and has strong affinity for iron, hence
depriving bacteria from using iron. It is also effective against a broad range of spoilage and pathogenic bacteria. Because egg albumin is allergy-causing in certain consumers, its widespread use as
a food preservative may be limited.
Protamine
Protamine is a cationic peptide derived from Salmon. It has broad-spectrum activity against grampositive and gram-negative bacteria and fungi. The antimicrobial activity is exerted by a strong electrostatic affinity of protamine to the negatively charged surface of bacteria during growth. It was found
to be highly inhibitory to Lis. monocytogenes, Clo. botulinum, Brochothrix thermosphacta, and Esc. coli.
Pleurocidin
Pleurocidin is a polypeptide present in mucosal and myeloid tissues of vertebrates and invertebrates. It has been isolated from the skin of flounder (fish) and has broad activity against grampositive and gram-negative bacteria including Lis. monocytogenes and Esc. coli O157:H7. It is heat
stable, salt tolerant, and nontoxic.
Defensins
Defensins are cationic antimicrobial peptides, produced by epithelial cells and immune cells, and
are responsible for natural immunity in mammals, insects, and birds. They have a broad range of
activity against bacteria, viruses, and fungi. Honeybee defensins exist as two peptides: defensins 1
and 2. Defensin 1 is synthesized in the salivary glands and is responsible for social immunity, and
defensin 2 is synthesized by hemolymph and is responsible for individual immunity. 4
Antimicrobials of Plant origin
Herbs and Spices 4,9,10
Herbs and spices of plant origin are added to foods to enhance flavors and fragrances, and they
possess antimicrobial activity. Antimicrobial activity is primarily associated with plant essential oils (EO), which are complex mixtures comprised of up to 45 different constituents, and
the active components are divided into four major groups based on their structure: (i) terpenes,
Lactoperoxidase
Lactoperoxidase is an enzyme (glycoprotein) and is naturally present in raw milk, colostrum, saliva,
and tears. The antimicrobial activity of lactoperoxidase is mediated by oxidizing thiocyanate (SCN−)
present in milk in the presence of hydrogen peroxide (H 2 O 2 ) to form hypothiocyanate (OSCN−) and
hypothiocyanous acid (HOSCN). Both OSCN− and HOSCN have antimicrobial activity against
pathogens, including Staphylococcus aureus, Lis. monocytogenes, Esc. coli O157:H7, Salmonella, and
Yersinia enterocolitica in food products such as beef, vegetable juices, milk, and liquid whole egg.
Ovotransferrin
Ovotransferrin, also known as conalbumin, is a glycoprotein present in egg whites, which also
possesses antimicrobial activity. It is a metalloprotease and has strong affinity for iron, hence
depriving bacteria from using iron. It is also effective against a broad range of spoilage and pathogenic bacteria. Because egg albumin is allergy-causing in certain consumers, its widespread use as
a food preservative may be limited.
Protamine
Protamine is a cationic peptide derived from Salmon. It has broad-spectrum activity against grampositive and gram-negative bacteria and fungi. The antimicrobial activity is exerted by a strong electrostatic affinity of protamine to the negatively charged surface of bacteria during growth. It was found
to be highly inhibitory to Lis. monocytogenes, Clo. botulinum, Brochothrix thermosphacta, and Esc. coli.
Pleurocidin
Pleurocidin is a polypeptide present in mucosal and myeloid tissues of vertebrates and invertebrates. It has been isolated from the skin of flounder (fish) and has broad activity against grampositive and gram-negative bacteria including Lis. monocytogenes and Esc. coli O157:H7. It is heat
stable, salt tolerant, and nontoxic.
Defensins
Defensins are cationic antimicrobial peptides, produced by epithelial cells and immune cells, and
are responsible for natural immunity in mammals, insects, and birds. They have a broad range of
activity against bacteria, viruses, and fungi. Honeybee defensins exist as two peptides: defensins 1
and 2. Defensin 1 is synthesized in the salivary glands and is responsible for social immunity, and
defensin 2 is synthesized by hemolymph and is responsible for individual immunity. 4
Antimicrobials of Plant origin
Herbs and Spices 4,9,10
Herbs and spices of plant origin are added to foods to enhance flavors and fragrances, and they
possess antimicrobial activity. Antimicrobial activity is primarily associated with plant essential oils (EO), which are complex mixtures comprised of up to 45 different constituents, and
the active components are divided into four major groups based on their structure: (i) terpenes,