Effects of ice containing three ethanolic plant extracts on formation and accumulation of biofilm communities on fish contact surfaces

Abstract

The effect of ice containing thyme (0.04% w/v), oregano (0.03% w/v) and clove (0.02% w/v) extracts on formation and accumulation of biofilm on high density polyethylene coupons during chilling storage of anchovy was investigated. The results showed that ice containing plant-extracts had no antibiofilm activity (p>0.05) against adherent mesophilic and Pseudomonas spp. bacteria during the early stages (< 3 days) of film formation and did not prevent biofilm adhesion. After 6 days of storage, significant inhibition on biofilm formation and accumulation (p<0.05) on high density polyethylene coupons was observed in the presence of plant extracts in ice; however, none of these plant extracts was able to inhibit cell adhesion completely. A lower biofilm inhibition (p<0.05) was observed with ice incorporated with thyme and clove-extracts after 9 and 12 days of storage compared to biofilm control, when a biofilm-reduction in adherent cell number (0.4 to 0.9 log cfu per coupon) was obtained for both microorganism indicators. Moreover, there was no significant difference in the effect of ice containing oregano-extract on biofilm formation and accumulation.