Nisin was first introduced commercially as a food preservative in the UK approximately 30 years ago. First established use was as a preservative in processed cheese products and since then numerous other applications in foods and beverages have been identified. It is currently recognised as a safe food preservative in approximately 50 countries. The established uses of nisin as a preservative in processed cheese, various pasteurised dairy products, and canned vegetables will be briefly reviewed. More recent applications of nisin include its use as a preservative in high moisture, hot baked flour products (crumpets) and pasteurised liquid egg. Renewed interest is evident in the use of nisin in natural cheese production. Considerable research has been carried out on the antilisterial properties of nisin in foods and a number of applications have been proposed. Uses of nisin to control spoilage lactic acid bacteria have been identified in beer, wine, alcohol production and low pH foods such as salad dressings. Further developments of nisin are likely to include synergistic action of nisin with chelators and other bacteriocins, and its use as an adjunct in novel food processing technology such as higher pressure sterilisation and electroporation. Production of highly purified nisin preparations and enhancement by chelators has led to interest in the use of nisin for human ulcer therapy, and mastitis control in cattle.

Anaerobic rumen fungi (phylum Neocallimastigomycota) occupy the gastrointestinal tract of several herbivorous animals, and by using their powerful hydrolytic enzymes and mechanical forces they degrade plant material in the rumen, essential for rumen efficiency. The rumen microbiome represents an underexplored resource for the discovery of novel microbial enzymes and metabolites, including antimicrobial peptides (AMPs). AMPs are promising drug candidates, and are necessary for targeting the worldwide issue of antimicrobial resistance. Rumen fluid and faecal samples were collected from various large herbivores, and fungal cultures were grown and maintained under anaerobic conditions. After roll tube culture to isolate single-zoospore cultures, sequencing of LSU was undertaken to identify the fungi to species level. Analysis of genomic data from these cultures, alongside published data was undertaken to explore the diversity of AMPs within these fungal genomes. Using functional and computational screening, potentially novel AMPs have been discovered, with isolates showing encouraging activity against some strains of bacteria. Findings indicate that the rumen microbiome may provide alternative antimicrobials for future therapeutic application.