Response of Bacterial Biofilms in Recirculating Aquaculture Systems to Various Sanitizers

Abstract

Pathogenic microorganisms may be incorporated into biofilms found in aquaculture systems, causing recurring exposure to potential disease agents. Aerobic plate counts, the presence of Enterobacteriaceae, and the presence of Escherichia coli, modified to express a green fluorescent protein (GFP E. coli), was used to evaluate the effectiveness of various sanitizers in decreasing bacterial incorporation into newly generated Robin K. King, U.S. Army Veterinary Corps, Veterinary Laboratory Europe, CMR 402, APO, AE 09180. JOURNAL OF APPLIED AQUACULTUREbiofilms in recirculating aquaculture systems. Disks of Buna-N rubber, polyvinyl chloride (PVC), chlorinated PVC, glass, fiberglass, and stainless steel were placed in aquariums stocked with Nile tilapia, Oreochromis niloticus. The effectiveness of water, an alkaline cleanser, sodium hypochlorite, a quaternary ammonium compound, or peracetic acid as a sanitizer was evaluated on each substrate by enumerating total plate counts, GFP E. coli, and Enterobacteriaceae. Sodium hypochlorite and peracetic acid were the most effective sanitizers, with an overall percentage reduction of GFP E. coli of approximately 2 logs 10 . The quaternary ammonium compound was moderately effective, 1 log 10 , against the target organisms. Water demonstrated a 2 log 10 reduction of the total plate count, suggesting that some mechanical cleaning was achieved. The type of material used as substrate for the biofilm had no significant (P > 0.05) effect on the effectiveness of the sanitizers.

Ozone: an emerging technology for the seafood industry

“…It has low molecular weight (MW = 48) whose three oxygen atoms chemically are arranged in chain. Ozone is then enriched oxygen (O 3 ) (Seafish, 1997;Tech Brief, 1999;King, 2001;Duguet, 2004;GuzelSeydim et al, 2004;Chawla, Bell and Marlene, 2007).…”

“…During the reaction with other molecules, ozone is destroyed. The final products of organic molecule oxidation with ozone are carbon dioxide and the water (Seafish, 1997;King, 2001;Campos et al, 2005;Campos et al, 2006;Vaz-Velho et al, 2006;Chawla, Bell and Marlene, 2007;Zentox, 2007). Unlike other biocides agents such as chlorine, the time necessary to make the disinfection is lower.…”

“…There are some articles that occasionally have been presented in conferences, and surely are also internal information of the institutes of fishing technology on the subject. Nevertheless, until now, there is little known about that (Seafish, 1997;Ravesi;Licciardello and Racicot, 1988;King, 2001). This review intends to offer a basic introduction on ozone, mainly its chemical properties, generation, antimicrobial properties, application on food surfaces, application on food plant equipment as an alternative sanitizer, and some of the potential uses that have been investigated until now, as well as the possible risks to the health and the security.…”

“…Any pathogen or contaminant that can be disinfected, altered or removed via an oxidation process will be affected by ozone. It is the strongest of all molecules available for disinfection in water treatment, and is second only to elemental fluorine in oxidizing power (Rice;Farquhar and Bollyky, 1982;Glaze;Kang and Chapin, 1987;Gibbs and Kirby, 1998;King, 2001;Duguet, 2004). Ozone use may have many advantages in the food industry.…”

“…Ozone use may have many advantages in the food industry. There are suggested applications of ozone in the food industry such as food surface hygiene, sanitation of food plant equipment, reuse of waste water, lowering biological oxygen demand (BOD) and chemical oxygen demand (COD) of food plant waste (Ravesi;Licciardello and Racicot, 1988;Brooks and Pierce, 1990;Rice, 1997;Tech Brief, 1999;King, 2001;Ibanoglu, 2002;Wu et al, 2007). In the United States, ozone has received in 1997 GRAS (Generally Recognized as Safe) classification, and in 2001 the FDA officially approved media containing ozone for use in the food industry, also for direct contact with food products, including fish, meat and poultry (Mielcke and Ried, 2004;Vaz-Velho et al, 2006;Zentox, 2007).…”