**5. Shelf-life extension of seafood products**

The short shelf-life of fresh seafood is a practical issue in the industries and distribution chain systems. Short shelf-life caused by chemical and microbial spoilage reactions can be stopped by traditional preservation methods but there is increasing interest in natural preservation methods. EOs are natural antioxidants and antimicrobials by which the shelf-life of seafood can be extended alone or in combination with other techniques. However, the reduction of antimicrobial effect of EOs in a food system due to some components of food and also the reverse action of EOs as antioxidant agents in some cases, has slowed down the use of them in practical systems.

Combination of EOs exhibit the synergistic antimicrobial activity. Thus, using of EOs into packaging can be the safe approach for food preservation technology [35]. The antimicrobial activity of gelatin-chitosan films incorporated with organo essential oil exhibited the great inhibitory effect through reducing the *E. coli*, *S. aureus*, *B. subtilis* and *B. entritidis* growth. Its inhibition zone was larger for Grampositive bacteria compared with Gram-negative bacteria. Furthermore, the lower total aerobic plate count and total volatile basic nitrogen values that can extend the shelf life of grass carp muscle was recorded in fish muscle packed with film containing the 4% organo essential oil. It seems the high percentage of carvacrol, eugenol, and thymol as phenolic components are responsible for this antimicrobial activity by damaging the cell membrane or interfere the enzyme functionality located on the cell wall. Moreover, the TVB-N value of sample packaged with gelatinchitosan-EOs film was lower compared with control and the shelf life of grass carp muscle packaged with the film containing EOs was extended to 12 days [36]. The same observation was gained from the gelatin-chitosan film incorporated with other EOs including clove, fennel, cypress, lavender, thyme, herb-of-cross, pine and rosemary for cod fillet preservation. Among all EOs, the high antimicrobial effect was obtained from clove against a wide range of food pathogen and spoilage bacteria such as *Salmonella*, *Lactobacillus*, *Listeria*, *Citrobacter*, *Escherichia*, *Yersinia*, *Brochothrix*, *Staphylococcus*, *Bacillus*, *Listeria*, *Clostridium*, *Aeromonas*, *Shewanella*, *Vibrio* and *Photobacterium*. In addition, the film containing the clove essential oil used for preservation of cod fillets, lowered the microorganisms in particular, *Entrobacteria*. Further, by delaying the formation of TVB-N, can extend the shelf life of chilled stored fish [37].

Immersion of salmon in marinade solution containing 1 w/w% essential oil from organo, cinnamon and thyme revealed that the antimicrobial effect, however, organo and cinnamon essential oil caused to enhance the shelf life of salmon and scampi. In addition, reduction of yeast and mold was observed by cinnamon (1%) addition in marinade for 6 days. Moreover, salmon treated with marinade containing 1% essential oil, shoed appropriate sensorial properties and high hedonic score

rather than 5% essential oil [38]. Combination of EOs with different types of packaging is another approach for enhancement of shelf life. For instance, the combination of cinnamon essential oil (1 w/w%) and MAP/vacuum packaging extend the shelf life of salmon. However, the MAP+ cinnamon had a better effect on salmon shelf life and the microbial shelf life reach nine or more days. While it was 6 days for vacuum packaged salmon treated with cinnamon. Moreover, cinnamon had no additional antimicrobial effect on LAB, when salmon stored vacuum or MAP [12].

Furthermore, the vacuum packaged common carp (*Cyprinus carpio*) stored 4°C had high quality with the combination of cinnamon essential oil. In addition, cinnamon essential oil inhibited the *Aeromonas* and *Lactococcus* on day 10. *Pseudomonas* and H2S-producing bacteria count was lower in treated fillets and did not exceed the microbial level of 7 log CFU/g at the end of the fillet's shelf life. Moreover, was effective in inhibition the increase of TVB-N and the accumulation of biogenic amines. TVB-N value fluctuated in 6.21 and 9.90 mg/100 g before 12 days treated sample contained and the highest value (15.15 mg/100 g) occurred at day 14. Moreover, crap fillets treated with cinnamon essential oil exhibited the acceptance longer sensorial shelf life (14 days) [39]. The Flounder fillet covered with clove essential oil agar films (0.5 g clove essential oil/g agar) had high low microbial count because of the great antimicrobial activity of clove essential oil against pathogens such as *Staphylococcus aureus*, *Yersinia enterocolitica*, *Aeromonas hydrophila*, *Debaryomyces hansenii* and *Listeria innocua*. The chemical indicators such as TVB-N was 25.83 mg TVB-N/100 g after 15 days of storage. The low total volatile bases and pH values and inhibitory effect on H2S producing microorganisms suggested clove essential oil could be suitable biopreservative for the flour fillet shelf life extension [40].

In another study, the active films accommodated by poly lactic acid enriched with ZnO nanoparticles (1.5%w/w) and *Zataria multiflora* Boiss (0.5, 1, 1.5%w/w) and the effect of this film on shelf-life extension of refrigerated *Otolithes ruber* fillet during 16 days was investigated. One aspect of shelf-life extension effect is the antibacterial activity of the films which in this case was conducted against *Escherichia coli*, *Salmonella enterica*, *Pseudomonas aeruginosa*, *Bacillus cereus* and *Staphylococcus aureus* by disc diffusion procedure. PLA/ZnO/ZEO and PLA/ZnO/MEO [*Zataria multiflora* Boiss. essential oil (ZEO) and *Menta piperita* L. essential oil] films demonstrated magnified antibacterial (691 and 513.33mm2 , respectively, against *S. aureus*). The authors expressed that according to the microbial count, the active film remarkably enhanced the shelf-life extension from 8 to 16 days. Chemical factors such as TBARS and TVB-N were also determined. The fillet wrapped with PLA/ ZnO containing 1.5% ZEO, showed the lowest TBARS (0.8 mg MA/kg muscle) and TVB-N (21.23 mg/100 g muscle). GC/MS analysis of EOs showed that the carvacrol and menthone were the major components of ZEO and MEO, respectively [41].

A new edible coating of pectin containing clove essential oil (CEO), was assessed to extension of bream (*Megalobrama ambycephala*) fillets shelf-life during 15 days. Physicochemical (pH, PV, TBA and TVB-N), microbiological (Total viable count, Psychrophilic bacteria, Lactic acid bacteria, *Enterobacteriaceae*, *Pseudomonas* spp., H2S producing bacteria) and organoleptic characteristics were analyzed to determine the influences of the pectin-CEO coating. Physicochemical analysis revealed that lipid oxidation decreased. Some other factors such as weight loss, water holding capacity, color, and texture of the fillets were improved as a result of coating with pectin-CEO (**Figure 3**). During 15 days, lactic acid bacteria were not affected by coating. However, the effects of coating on bacterial growth, especially on Gram-negative bacteria, was observed [42].

The effect of chitosan, thyme essential oil and their combination, on the shelflife of vacuum packaged smoked eel fillets at 4°C, was investigated and according to sensory odor analysis the shelf-life of chitosan/thyme and chitosan-thyme

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*Application of Essential Oils for Shelf-Life Extension of Seafood Products*

TVB-N in fish and fishery products is 35 mg N/100 g [44].

combination treated samples extended 1 and >2 weeks, respectively, compared with than control sample (35 days for control). The control sample showed a significantly higher thiobarbituric acid value compared chitosan-thyme combination treated sample. Control, thyme, chitosan, and chitosan-thyme combination treated samples showed TVB-N values below the maximum permissible level (35 mg N/100 g) in fish and fishery products which was 31.5, 18.1, 14.9, and 13.1 mg N/100 g in 35 and 42, 49 days of storage, respectively [43]. The maximum permissible level of

During the past decades, EOs have achieved great attention due to their food preservation effects, particularly for the antimicrobial and antioxidant effects. The EOs of different sources from land and the seas, have variety of phenolic and non-phenolic components which the most actives are low molecular weight terpenoids, terpenes, and aliphatic chemicals (obtained data from analysis by GC-MS and GC/FID in literature). These EOs have shown significant antioxidant, antimicrobial activities which can extent the shelf-life of seafood products. However, it is

Marzieh Moosavi-Nasab1,2\*, Armin Mirzapour-Kouhdasht1,2 and Najme Oliyaei1,2

2 Seafood Processing Research Group, School of Agriculture, Shiraz University,

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

1 Department of Food Science and Technology, School of Agriculture,

\*Address all correspondence to: marzieh.moosavi-nasab@mail.mcgill.ca

still mandatory to inquire into cytotoxicity and toxicity of these EOs.

The authors declare no conflict of interest.

*DOI: http://dx.doi.org/10.5772/intechopen.86574*

**6. Conclusions**

**Conflict of interest**

**Author details**

Shiraz, Iran

Shiraz University, Shiraz, Iran

provided the original work is properly cited.

*Application of Essential Oils for Shelf-Life Extension of Seafood Products DOI: http://dx.doi.org/10.5772/intechopen.86574*

combination treated samples extended 1 and >2 weeks, respectively, compared with than control sample (35 days for control). The control sample showed a significantly higher thiobarbituric acid value compared chitosan-thyme combination treated sample. Control, thyme, chitosan, and chitosan-thyme combination treated samples showed TVB-N values below the maximum permissible level (35 mg N/100 g) in fish and fishery products which was 31.5, 18.1, 14.9, and 13.1 mg N/100 g in 35 and 42, 49 days of storage, respectively [43]. The maximum permissible level of TVB-N in fish and fishery products is 35 mg N/100 g [44].
