- • Nisin (E234) provides bactericidal and sporicidal action against clostridia. It is active against the butyric swelling in hard cheese due to late development of Clostridium tyrobutyricum.
- • Nisin is permitted in ripened cheese and processed cheese, certain puddings, clotted cream, liquid eggs, and mascarpone. Nisin is also permitted in over 40 countries worldwide including the United States, Australia, South Africa, Russia, and India for use as antimicrobial agent in a variety of food products. The AFC Panel evaluated nisin in January 2006 and endorsed the ADI of 0.13 mg nisin/kg bw per day established by the SCF in 1990 (EFSA, 2006).
- • In the United States, nisin is considered GRAS, and it is approved as a “nisin preparation”
- (21 CFR 184.1538) containing nisin, a group of related peptides with antibiotic activity, with nisin content not less than 900 IU/mg. The ingredient is used at levels not exceeding good manufacturing practice in order to reach a maximum of 250 parts per million of nisin in the finished product. It is allowed in pasteurized cheese spreads and pasteurized process cheese spreads; pasteurized cheese spread with fruits, vegetables, or meats.
- • Liposome-encapsuled nisin has enhanced antimicrobial activity in cheese and has been used to control the growth of bacteria during storage. It was shown that the liposomal formulation could be used for the control of foodborne pathogens in cheese (Colas et al., 2007). The use of nisin in its free form is associated with loss of activity due to degradation or deactivation and emergence of nisin-resistant bacterial strains. Liposomal nisin acts as a long-term preservative with controlled release properties.
- • Natamycin (E235) is the generic name approved by the World Health Organization— it is synonymous with pimaricin, a name used in earlier literature. Natamycin may be used for the surface treatment of semi-hard and semi-soft cheese, and dry, cured sausage at a maximum level of 1 mg/dm2 in the outer 5 mm of the surface. ADI, assigned by JECFA, is 0.3 mg/kg bw/day (1968, 1976, 2002).
These levels of natamycin are not a safety issue as far as the induction of antimicrobial resistance is concerned, provided it is only used for the surface treatment of the rind of semi-hard and semi-soft cheese and on the casings of certain sausages. In the United States, natamycin is considered as a direct food additive and is approved for use in cheese making as a mold spoilage inhibitor (21 CFR 172.155). The additive may be applied on cheese, as an antimycotic, in amounts not exceeding 20 milligrams per kilogram (20 parts per million) in the finished product.
• Lysozyme (E1105), is a mucolytic enzyme capable to degrade bacterial cell walls, it is used to prevent swelling in long ripened hard cheeses like Grana, Montasio, Provolone, Asiago ed Emmental. Its use is allowed by some POD Consortium like Grana Padano.
The Consortium of Producers of Parmigiano Reggiano POD cheese excludes its use by ensuring a controlled diet of dairy cows.
Lysozyme is one of the few naturally occurring antimicrobials approved by regulatory agencies for use in foods. In Europe, lysozyme is used to prevent gas formation (blowing) in cheeses such as edam and gouda by Clostridium tyrobutyricum (Wasserfall et al., 1976; Carini and Lodi, 1982). Cheese manufacturers use egg white lysozyme for this purpose. It is added into cheese milk at a maximum of 400 mg/L.
A tentative final rule (FR 1998. 63:12421-12426) listing egg white lysozyme as a “directfood substance affirmed as generally recognized as safe” (21 CFR 184.1550) was published by FDA in 1998. The enzyme is allowed to be used in cheeses to prevent gas formation. Lysozyme is used to a great extent in Japan to preserve seafood, vegetables, pasta, and salads. Lysozyme has been evaluated for use as a component of antimicrobial packaging (Padgett et al., 1998).
Since egg whites have been used for food since the beginning of recorded history, there is little concern by regulatory agencies about the toxicity of lysozyme. However, there is the potential risk for allergenicity to the protein.