Decades-old canned salmon has unveiled valuable insights into the health of marine ecosystems. A group of American scientists examined over 170 cans of salmon, some dating back 50 years, leading to groundbreaking discoveries.
An Ancient Yet Informative Parasite
Researchers at the University of Washington recently studied canned salmon specimens from 1979 through 2021. Among these, one can, which had expired fifty years prior, drew their particular interest. Inside, they found anisaquídes, marine parasites remarkably preserved by the canning procedure.
Rather than indicating a hazard, this finding was a highly positive ecological signal. Contrary to suggesting poor quality, the presence of these parasites actually points to a thriving marine environment.
Chelsea Wood, a co-author of the research, emphasized, “The presence of anisaquídes signals that the fish on your plate comes from a healthy marine ecosystem.”
These parasites have a complex life cycle: first, they are ingested by krill, then transferred to fish such as salmon, and finally develop in the intestines of marine mammals. Their existence and abundance are therefore intimately linked to the balance of an entire food chain.
By comparing cans from various decades, the team noticed a steady increase in the number of anisaquídes found in salmon over time. This trend may indicate a stable or even recovering ecosystem.
However, other explanations are also being explored, including the effects of climate change or the growth of marine mammal populations in the North Pacific region.
From Ecological Sentinels to Potential Health Risks
Although fascinating scientifically, these parasites can sometimes pose health risks to humans. Under specific circumstances, they may cause severe foodborne illness.
This dual nature presents a dilemma: how can their crucial ecological role be balanced against the risks they pose to the food supply? Considerable efforts are underway to mitigate these dangers. Fish intended to be eaten raw, canned, or dried must be cooked at 60°C for at least one minute or frozen for a minimum of five days before consumption.
However, in the case of canned fish, the issue is resolved upfront since the sterilization process used during canning destroys any potential hazards, ensuring the fish is completely safe to eat.
The researchers’ future plans include examining older canned foods in greater detail to develop a deeper understanding of long-term ecological changes and the impacts of climate change on marine life. This ambitious work began with something as simple as a forgotten can of salmon tucked away in a cupboard.
