Effect of modified atmosphere packaging on the TVB/TMA-producing microflora of cod fillets

Abstract

R eceived 28 A pril 1995; revised 28 N o v em b er 1995; accepted 31 J a n u a ry 1996 AbstractCod fillets (Gadus morhua) were packed under modified atmospheres, with four differ ent gas com positions (60% CO2-10% Or 30% N 2, 60% COr 20% Or 20% N 2, 60% C O r 30% O2-10% N 2, 60% CO2-40% 0 2), and stored at 6°C. Plate counts were carried out after 3, 4, 5, 6 and 7 days, to follow the growth o f aerobic and anaerobic bacteria, lactic acid bacteria, H 2S-producing bacteria and Enterobacteriaceae. The production o f total volatile bases (TVB) and trimethylamine (TM A), and the changes in pH o f the fillets were measured. Modified atm osphere packaging (MAP) had in general an inhibitory effect on the growth o f the microflora but limited inhibition of the production o f TVB and TM A. Despite the fact th at increased oxygen proportions in the atm osphere contributed in a slightly lower production o f TM A, all the samples had a TVB and TM A content high enough to be considered as spoiled after 4 days' storage at 6°C. A total aerobic plate count at 25°C o f a IO6 cfu/g, combined with the presence o f only a IO3 cfu/g of H 2S-producing bacteria, which are normally considered as TM A O -reducing organisms in fish, cannot explain the strong increase in TM A. A high cell concentration o f m ore than IO8 cfu/g of Shewanella putrefaciens is required for production o f a TM A level normally found in spoiled fish. This suggests that there could be another type of bacterium in fish, n ot involved in the spoilage o f unpacked fish, which is resistant to 60% C 0 2, is not H2S-producing, and shows a high TM AO-reducing capacity. This bacterium could be Photobacterium phosphoreum.

Shelf-life of Chilled Muscle Tissue of the Common Carp (Cyprinus carpio L.) Packaged in Carbon Monoxide Enriched Modified Atmosphere

“…In our experiment, too, pH values never dropped below that limit. Acidulation of fish muscle in MAP may partly be due to CO 2 diffusion to the tissue accompanied by the formation of carbonic acid (Ruiz-Capillas and Moral 2001; Debevere andBoskou 1996). Another factor participating in acidulation of fish meat in MAP mentioned by Stenström (1985) are acid products of micro-organisms present in the meat.…”

“…The packaging gas to the packaged product volume ratio should be from 2:1 to 3:1 (Sivertsvik et al 2002). CO 2 is used as an antimicrobial component (Debevere and Boskou 1996), N 2 as inert gas retarding the oxidative rancidity (Farber 1991; Church 1998 and O 2 as a prevention of proliferation of anaerobic micro-organisms (Clostridium spp.) and red meat colour stabilizer by oxidation of myoglobin and formation of oxymyoglobin (Arashisar et al 2004; Özogul et al 2004.…”

Physical and Chemical Changes in Fresh Chilled Muscle Tissue of Common Carp (Cyprinus carpio L.) Packed in a Modified Atmosphere

“…It inhibits the growth of spoilage organisms, particularly Shewanella putrefaciens, Pseudomonas, Vibrio and Aeromonas spp. that produce H 2 S (Jensen et al 1980;Debevere and Boskou 1996). When applied, it also retards the oxidation reaction.…”

Optimal Modified Atmosphere for Packaging and its Effects on Quality and Shelf-life of Pacific White Shrimp (<i>Litopenaeus vannamei</i>) under Controlled Freezing-point Storage at −0.8°C

“…5), which was related to the activity of spoilage bacteria and endogenous enzymes that resulted in the formation of compounds including ammonia and primary, secondary and tertiary amines imparting characteristic off-flavors to shrimp (Debevere and Boskou, 1996;Ruiz-Capillas and Moral, 2001).…”