Funded by

An investigation of the microbiological and biochemical properties leading to an extended shelf-life in Goldband Snapper (Pristomoides multidens)

Student: Rachel Tonkin

Supervisors: Dr Hannah Williams, Prof. Thomas Riley and Mr. Steven Munyard

Goldband Snapper: The answer to a longer shelf life?

Background

• Results from ice storage trials concluded that Goldband Snapper was still acceptable after 5 weeks storage (Ames, 1985)

• Fish harvested from warmer waters (21-23°C) have a longer shelf life in comparison to fish harvested from colder waters (8-14°C) (Sumner & Magno-Orejana, 1985)

• How does this compare to other fish harvested from the same catchment area in Western Australia?

Goldband and Saddletail Snapper

• Goldband Snapper(Pristipomoides multidens ) Family: Lutjanidae Order: Perciformes Class: Actinopterygii

• Environment: Demersal (bottom feeders) Marine Depth range 40-245m Tropical and sub-tropical

waters

• Saddletail Snapper(Lutjanus malabaricus )

Family: Lutjanidae Order: Perciformes Class: Actinopterygii

• Environment: Reef associated Marine Depth range 12-100m Tropical waters

Objectives

• Validate the Quality Index Scheme for Saddletail Snapper using Western Australian caught Saddletail Snapper

• Perform shelf life analysis

• Determine microbial flora on fish• Assess Biochemical, physical and sensory

changes over time

• Analyze data for significant indicators

• Make recommendations for shelf life extension in tropical fish species

Quality Index method for Saddletail Snapper

Day 3

Day 17

Day 31

QIM validation Sessions for Saddletail Snapper

Day 3Day 17Day 31

Panelists assessing Saddletail Snapper using the Quality Index Method

Panelists assessing cooked Saddletail Snapper fillets using the Torry Scheme

Sensory Analysis

Microbiological Analysis

Bacterial counts from QIM validation sessions

1

100

10000

1E+06

1E+08

1E+10

1E+12

1E+14

0 5 10 15 20 25 30 35

Storage Time (Days on ice)

Bact

eria

l cou

nts

(cfu

/ml)

Iron Agar

Plate Count Agar

Long and Hammer Agar

Future Work

• Complete the biochemical testing on samples collected during the validation for the QIM of Saddletail Snapper

• Complete further texture analysis on the fillets of Saddletail Snapper

• Investigate the differences in microbiology and shelf life of Saddletail and Goldband caught from different depths

• Complete further microbiological analysis of bacteria isolated from further Goldband and Saddletail Snapper samples

References

•Allen, P., Bennett, K. (2008). SPSS For the Health and Behavioural Sciences. Nelson Australia Pty Ltd.

•Ames, G. R., & Curran, C. A. (1985). Report on a Visit to Vanuatu to Conduct Iced Storage Trials on Fish Species of Commercial Importance (No. H1422). London: Tropical Development and Research Institute.

• Martinsdottir, E., Sveinsdottir, K., Luten, J. B., Schelvis-Smit, R., & Hyldig, G. (2001). Sensory Evaluation of Fish Freshness, Reference Manual for the Fish Sector: QIM Eurofish

•Ames, G. R., & Curran, C. A. (1985). Report on a Visit to Vanuatu to Conduct Iced Storage Trials on Fish Species of Commercial Importance (No. H1422). London: Tropical Development and Research Institute..