Effect of absorbent pads containing black seed or rosemary oils on the shelf life of sardine [Sardina pilchardus (Walbaum, 1792)] fillets

The effects of essential oils on the shelf life of sardine (Sardina pilchardus) fillets in cold storage were assessed at 4–6°C. The oils were sprayed on the fillets as well as with the addition of absorbent food pads that also contained essential oils. Sardine fillets were divided into eight test groups. Group A: fillets stored without treatment (control group); Group B: fillets packaged with food pads (without the addition of essential oils); Group C: Rosemary oil sprayed onto food pads (10 ml of 1.5% RO); Group D: Black seed oil sprayed onto the food pads (10 ml of 1.5%BSO); Group E: Rosemary oil sprayed onto both sides of the sardine fillets (10 ml of 1.5%RO); Group F: Black seed oil sprayed onto both sides of sardine fillets (10 ml of 1.5% BO); Group G: Rosemary oil sprayed onto both sides of the sardine fillets (10 ml of 1.5% RO) and on the food pads (+10 ml of 1.5% RO); and Group H: Black seed oil sprayed onto the sardine fillets and the food pads (10 ml of 1.5% BSO onto both sides of fillets +10 ml of 1.5% BSO onto food pads). Tests were carried out at days 0, 3, 5 and 7. When compared to the control group, food pads containing rosemary and black seed oils extended the shelf life of sardine fillets by approximately 2 days at 4–6°C. Group A and B exceeded the limit of consumption on day 3, and Group C and D exceeded this microbiological limit after day 5. RO and BSO both exhibited the same antimicrobial effects on the shelf life of sardine fillets. Groups E, F, G and H prolonged the microbiological threshold by 7 days compared to the control. However, Group G and H had 1–1.5 log lower TVC load than Group E and F. Food pads containing antimicrobial essential oils may be used to extend the shelf life of fresh fish, however, further investigations are needed to determine safety standards.