https://doi.org/10.17113/ftb.64.02.26.9023

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Preservation of Raw Crassostrea gigas Oyster Meat: Effects of Weak Organic Acid Marination on Physicochemical, Microbiological, and Sensory Properties

Name Surname¹, Name Surname², Name Surname², Name Surname¹, Name Surname¹ and Name Surname^1*

¹Department of Food Science and Technology, Federal University of Santa Catarina, Admar Gonzaga Highway, n.1346, Florianópolis, SC 88034-000, Brazil

²Center for Aquaculture and Fisheries Development, Agricultural Research and Rural Extension Company of Santa Catarina, Admar Gonzaga Highway, n.1188, Florianópolis, SC 88034-000, Brazil

Copyright © 2024 This is a Diamond Open Access article published under CC-BY licence. Copyright remains with the authors, who grant third parties the unrestricted right to use, copy, distribute and reproduce the article as long as the original author(s) and source are acknowledged.

Article history:

Received: 29 December 2024

Accepted: 26 November 2025

Keywords:

bivalve molluscs; oyster meat; shellfish consumption; shelf life; sensory analysis; semi-preserved products

Summary:

Research background. Oysters have high nutritional value; however, their short shelf life limits their commercialization to areas close to production sites. Affordable and accessible processing techniques that extend shelf life could expand both market reach and consumer access to oysters. This study evaluated the physicochemical, microbiological, and sensory properties of raw Crassostrea gigas oyster meat semi-preserved with weak organic acids and saline solutions under refrigerated storage (4 °C).

Experimental approach. Aliquots of (100±2) g of raw oyster meat were placed into plastic containers containing different solutions: W - sterile deionized water only (negative control treatment); NaCl – base solution (NaCl, 5 % m/V) only; CA – base solution with 2 % citric acid; LA – base solution with 2 % lactic acid; AA – base solution with 2 % acetic acid. Sensory, physicochemical and microbiological characteristics of the semi-preserves were monitored for 16 days.

Results and conclusions. Incorporating weak acids into the marination solutions effectively inhibited the growth of mesophilic and psychrotrophic bacteria in semi-preserved oysters during 16 days of refrigerated storage. In contrast, W and NaCl treatments exceeded the recommended limit of 5 log CFU/g for seafood after 3 and 11 days, respectively. By day 16, TVB N values indicated early spoilage in W (30.03±1.1) mg/100 g, satisfactory freshness in NaCl (24.53±2.6) mg/100 g and CA (18.33±1.1) mg/100 g, and excellent freshness in LA (14.70±0.0) mg/100 g and AA (14.95±1.8) mg/100 g. TBARS values remained below 3 mg MDA/kg in all treatments, indicating good oxidative stability. Among the acids, AA maintained higher pH values (~3.78 at day 16) than CA (~3.26) and LA (~3.14) and showed the lowest microbial loads; however, it received the highest scores for acid odour (median=5.35) and the lowest for characteristic oyster odour. CA and LA produced sensory profiles more similar to fresh oysters, with higher characteristic odour scores and lower acid odour scores, but slightly higher spoiled odour scores (still low in absolute terms). Overall, AA was the most effective for microbiological and physicochemical preservation, while CA and LA offered better sensory acceptance. These results highlight the potential of weak organic acids, particularly AA, as a low-cost method to extend the shelf life of raw oysters to at least 16 days under refrigeration.

Novelty and scientific contribution. This study evaluated the effects of marination with weak acids on the physicochemical, microbiological, and sensory properties of raw oyster meat. The wide range of parameters analysed highlights not only its suitability for consumption but also consumer preferences based on sensory aspects such as colour and odour. The combined findings can assist the industry in selecting the most appropriate acid for developing different oyster-based products.