Natamycin is known for its efficacy in controlling fungi growth and pays way to be a preservative in the food industry for more than 30 years . It is a natural preservative derived from a microorganism known as Streptomyces natalensis. Food industries utilize natamycin for its preservative effect on food products like cheese, sausages, yogurts, juices, and wines, etc.. It is most commonly preferred over the other preservatives as it is free from odor and color. 

World Health Organization (WHO), European Food Safety Authority (EFSA), and Food and drug administration (FDA) has listed it as generally recognized as safe (GRAS) status after thorough evaluation, and being considered as a natural preservative by the European Union and labeled with E number (EEC No. 235). 

Applications of natamycin in Dairy products

Natamycin has been commonly used in dairy products worldwide. Due to its low solubility, it is generally applied on the food products surfaces to enhance their shelf life. An advantage of nataycin over use of sorbates in the limited migration characteristics into the food matrix (Elsser-Gravesen and Elsser-Gravesen et al., 2013). Cheese is the major dairy product where the application of natamycin plays a role for several years. Cheese is susceptible to mold growth due to the large surface area on exposure to the external environment. Mold contamination results in the formation of metabolites that could induce undesirable flavors and aroma to it. Production of carcinogenic mycotoxin by molds is the biggest threat for cheesemakers. Natamycin showed the best inhibitory action at 20 ppm with an increased shelf life of cheese up to 4 weeks. The combination of preservatives is an excellent approach to enhance the shelf life as well as the consumer acceptance of the food products. Natamycin and nisin acted synergistically and increased the shelf of Galoytri cheese (traditional Greek cheese) for more than 28 days by inhibiting the yeast and molds (Kallinteri et al., 2013). The application of natamycin on cheese can be done by spraying, dipping, coating emulsions, and direct addition.

Studies showed that plain yogurt treated with natamycin (10 ppm) was reported to have a shelf life up to 40 days as e yeast and mold growth was reduced (3.36 ± 0.66 log 10 cfu/g) (Sara et al., 2014). Natamycin at the concentration of 8–10 ppm was shown to reduce the yeast counts up to 65.99 % in vanilla-flavored yogurt stored at 5 ± 1 °C without altering their native sensory attributes (Dzigbordi et al., 2013). Growth of Mucor circinelloides (involved in bloating the container) in yogurt was inhibited by applying 8 ppm of natamycin to yogurt (refrigerated at 15 °C) resulted in shelf-life extension of up to 30 days without compromising the sensory aspects. The application of natamycin as an anti-fungal preservative and its effect on shelf life is detailed in Table .

Table 

Applications of natamycin in Meat and meat products

The primary application of natamycin are indented for surface treatment of fermented sausages. The codex commission has set maximum permitted levels of natamycin in cured meat, game meats, dried and processed meat as 6 mg/kg with penetration depth of not more 5 mm (Lee and Paik, 2016). Meat Sausages have a larger surface area, thereby acting as a medium for undesirable mold growth. Specifically in case of fermented sausages where ripenining casues decrease in various volatile compounds like carbonyl, carboxylic acids, alcohols, phenols, etc. are formed during smoking. These volatiles not only imparts aroma and flavor to sausage but also acts as an antifungal agent (Ledesma et al., 2016). Sausages are also treated with different preservatives like sorbic acid, potassium sorbate, natamycin, etc. to extend the shelf life and minimize the losses by fungal growth. However, Natamycin showed a better antimycotic effect on sausages that were heat-treated and fermented than sorbates (Pipek et al., 2010). A combination of natamycin, sodium lactate, and nisin was used to suppress mold growth on emulsion-type sausages and extend their shelf life (Jingwei and Yunxia, 2009). 

A dosage of 300 ppm of natamycin reduced the chances of Aspergillus niger contamination by 44.80% on minced beef meat and kept the overall acceptability intact for 8 days (Salem et al., 2016). The combination of several preservatives like nisin, natamycin and polylysine at the concentration of 0.1, 0.05, and 0.1 shows inhibition ration of 95.1% against the spoilage microbes in ham Xuan et al., 2013). Matari et al. (2017) studied the effect of irradiation and natamycin treatment on yeast and mould counts in the 60 samples of fresh minced meat. They found that samples treated with 0.1% of natamycin showed significant decrease in yeast and mould count at 0, 5, 10 and 15 days of storage at 4 °C. Nevertheless, application of natamycin is well known in the poultry feed industry to control the disease caused by Aspergillus without interfering in the growth performance of broiler.

Applications of natamycin in Bakery products

Baked goods are susceptible to spoilage by mold, the pattern, and incidence of which depends on the food's moisture content. Most of the baked items like cake, pastries, bread, and muffins have high water activity (aw), due to which they get spoil rapidly. The molds that are associated with the spoilage are Penicillium (P. chrysogenum, P. brevicompactum, and P. roqueferti), Mucor, Aspergillus, Rhizopus, Wallemia, Chrysonilia sitophila, and Eurotium respectively (Saranraj and Geetha 2012).

Although the baking temperatures are sufficient for the inhibition of fungi, their vegetative cells, and mold spores, nevertheless mold spores can recontaminate the baked product during post-processing (Ponte and Tsen, 1987). Several chemical preservatives (sorbate and propionate) are utilized for the inhibition of molds in baked goods. These preservatives are proved to be ineffective at pH 6 (normal pH of baked goods) and give an inappropriate taste to the baked commodities (Seiler, 1964). In addition, several strains of yeast and mold like Monascus ruber and pencillium roqueforti has degrade sorbate or propionic acid preservatives. Treatment of baked products with natamycin can enhance the shelf life without destroying the taste and other sensory attributes. Moreover, addition of natamycin in dough would inhibit yeast fermentation. Studies on vacuum packed Psyllo (pastry product) by treatment of chitosan and natamycin on shelf life extension by inhibition of spoilage microflora was studied by Tsiraki et al. (2018). They found that Chitosan at 1.5%, w/v and natamycin at 10 mg/L, w/v showed have significant effect on yeast and mould count by extending the shelf life upto 11 days without affecting the sensorial characteristics. The detailed study on application of natamycin on surface of various baked goods were extensively reviewed by Delves-Broughton et al. (2010). USFDA has set permissible levels for addition of natamycin for various bakery products as 14 mg/kg for bread, 20 mg/kg for tortillas, 7 mg/kg for US style muffins. Similarly in China, natamycin residue in moon cakes should not exceed 10 mg/kg.

Quote: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8595390/#