**12.** *Zingiber officinale* **is used as a preservative**

*Z. officinale* is a well-known spice that contains polyphenolic compounds such as 6-gingerol and its derivatives. These chemical constituents make ginger a powerful antioxidant [58]. Fresh ginger is high in proteins, fiber, water, lipids, minerals, and carbohydrates, such as calcium and iron [59]. *Z. officinale* CO2 extracts have been demonstrated to have high polyphenol content and to operate better as an antioxidant preservative early in the fat oxidation process. *Z. officinale* exhibits antioxidant activity comparable to BHT, a chemical antioxidant that suppresses peroxidation at temperatures ranging from 37 to 80% [59]. *Z. officinale* has been shown to inhibit the growth of colon bacteria as well as other pathogens, such as *Salmonella*, *E. coli*, *Staphylococci*, *Proteus sp*, and *Streptococci* [60–62]. *Z. officinale* has antifungal activity against a variety of fungi, including *Aspergillus* [63]. The phenolic compounds in ginger work as denaturing agents, preventing microbial growth by modifying cell permeability and causing bacterial cells to shatter. Most phenolic compounds are metal chelators that bind to active sites of metabolic enzymes, limiting enzyme activity as well as bacterial metabolism and reproduction [64]. Ginger extracts at 0.4 mg/ mL have been proven in tests to be more effective than commercial antibiotics, such as gentamicin against *Klebsiella pneumoniae*, *Proteus vulgaris*, *Streptococcus pyogenes*, and *S. aureus* [65].

### **13. Curry is used as a preservative**

Curry is a common spice found in cooking. It originated in India and has since gained popularity throughout the world because of its distinctive flavor and aroma [66]. Curry has been shown to have powerful antimicrobial effects. Antimicrobial tests with coumarin extracts in petroleum ether and chloroform demonstrated considerable antibacterial and antifungal action. Curry chloroform extract has shown good inhibitory efficacy against *A. niger* and *P. aeruginosa* [67]. Curry is high in carbazole alkaloids and coumarins, both of which have antimicrobial qualities. Curry compounds have been found to have minimal inhibitory values ranging from 3.13 to 100 mg/mL [68].

The antibacterial activity of curry extracts is proportional to the concentration used, and growth inhibition has been seen against *P. aeruginosa, E. coli*, and *B. subtilis*, with a lower minimum inhibitory concentration (MIC) than *S. aureus* and *Micrococcus luteus*. According to these findings, *E. coli* is the most resistant bacteria, and higher spice doses are required to halt it [67]. Curry's antifungal and antiaflatoxigenic properties have been demonstrated. The use of curry as a natural antibacterial food preservative and a detoxifying agent during the food preservation process has been studied [69]. Because of these features, curry has established itself as an important natural preservative with an enormous potential for replacing other types of nonnatural preservatives. Whole spices can be used as preservatives on their own, but their essential oils can be isolated and evaluated for quality. Spice essential oils are homogeneous mixtures of organic chemical molecules belonging to the same chemical family, such as sesquiterpenes, monoterpenes, and terpenoids.

*Herbs and Spices' Antimicrobial Properties and Possible Use in the Food Sector DOI: http://dx.doi.org/10.5772/intechopen.108143*
