Reducing food waste: can we keep open canned sardines in the refrigerator?

Researchers from the University of Porto studied the shelf life at 4°C of open canned sardines, depending on the type of seasoning (sardines in brine, vegetable oil, tomato sauce).

A team of researchers from the University of Porto in Portugal examined the shelf life of canned sardines after opening to increase consumer awareness of their quality and safety and reduce food waste. Indeed, canned fish has a high shelf life, but after opening, it undergoes microbiological and chemical changes that compromise its stability. Yet, depending on can size, a consumer may not eat the full content.


The researchers tested the microbiological, sensorial, physical and chemical stability of 40 cans for three product types: sardines in light brine, sardines in vegetable oil and sardines in tomato sauce. They found that the shelf life of canned sardines after opening was strongly affected by the type of sauce. Sardines canned in tomato sauce can be refrigerated for up to three days without substantial chemical, microbiological or sensory modifications, while sardines in brine or vegetable oil should only be kept up to one day at 4 °C due to proteolysis and sensorial defects, respectively.


According to their sensorial analysis, sardines in tomato sauce started showing significant changes only after day 4, while deviations in some attributes like colour, putrid odour and putrid flavour were not detected even at day 7. The tomato sauce gave a more intense flavour and odour, thus hindering the sensorial perception of deterioration. 


The results of their microbiological analysis suggested that all three product types could be considered edible for up to seven days. Indeed, bacterial microorganisms were absent in sardines in tomato sauce.  In the samples of sardines in light brine and sardines in vegetable oil, bacterial micro-organisms were present within an acceptable range for ready-to-eat food. However, the authors advice that the aseptic measures employed during their study may not reflect the reality of the domestic environment.




Cruz, R.; Pereira, V.; Pinho, T.; Ferreira, I.; Novais, C.; Casal, S. Safety and Quality of Canned Sardines after Opening: A Shelf-Stability Study. Foods 2022, 11(7), 991;


Image credits: Image par monicore de Pixabay