Original report by
Hudaa Neetoo, Senior Lecturer, Faculty of Agriculture, University of Mauritius
Summary
Mauritius sits surrounded by one of the largest ocean territories in Southern and Eastern Africa – a massive 2.3 million square kilometers of waters. This vast marine area has made fishing and fish farming central to the island nation’s economy and diet. Unfortunately, seafood is highly perishable, characterised by a short life span, because of ample opportunities for microbial contamination and growth. As a result, microbial spoilage of fish causes the industry to incur significant economic losses.
A nation built on the sea
Thanks to its large maritime zone, Mauritius enjoys an incredible diversity of fish species. From colorful reef fish swimming in shallow lagoons to various tuna species living in the deep ocean, the waters provide both food and income for thousands of people. As locals become more prosperous, fresh fish has become an increasingly important part of their daily meals.
However, seafood can easily become contaminated by microorganisms from seawater. Unlike other foods, fish and shellfish provide perfect conditions for disease-causing or spoilage bacteria to multiply rapidly, leading to significant economic losses or compromised health risks.
The hidden danger of Vibrio bacteria
One of the most concerning threats comes from Vibrio bacteria, which thrive in both tropical and temperate waters. A recent study conducted in Mauritius has found these microorganisms in both wild-caught fish (like parrotfish, emperor fish, and grouper) and farmed species.
What makes this particularly worrying is that many of these vibrios carry genes that allow them to cause disease to humans and at the same time confer resistance to multiple antibiotics, commonly used in treatments, like tetracycline and penicillin. This means infections could be harder to treat if people get sick, underscoring the need for adequate cooking to inactivate these microorganisms.
Histamine in popular fish
Local consumers are also fond of open-sea fish such as tuna, marlin, and mackerel. But when these fish are not kept at an adequately low temperature, bacteria can convert natural compounds in the fish into histamine, a chemical that causes food poisoning.
Even dangerously high levels of histamine do not change how the fish looks, smells, or tastes, making it a problem for both retailers and consumers. Research found that big-eye tuna sold in local wet markets in Mauritius was left sitting at room temperature for up to eight hours. While histamine levels increased during this time, they fortunately stayed below dangerous limits. However, the overall quality of the fish deteriorated significantly, with harmful bacteria multiplying rapidly.
Shelf-life issues for shellfish and sea urchins
Oysters, mussels, and sea urchins have become increasingly popular in Mauritius, both among locals and tourists. In fact, sea urchins are highly valued for their gonads, which are rich in protein but low in fat and carbohydrates, making them a popular low-calorie delicacy.
But shellfish and sea urchins often harbor high levels of bacteria, making them more perishable than other high-protein muscle foods. A study conducted in Mauritius found that raw sea urchins freshly harvested from the sea also contained higher levels of Vibrio bacteria than finfish or oysters, making continuous monitoring of the microbiological safety and quality an imperative.
Viruses
An often-overlooked threat comes from viruses, infectious particles measuring only a few nanometres in size. A small study conducted in Mauritius [A4] found that 60% of the oysters that were sampled and tested, revealed the presence of human norovirus, an agent that causes severe stomach illness.
For people who enjoy eating raw oysters “on the half-shell,” this represents a moderate risk of infection. It’s worth noting that Mauritius has no regulations or standards for viral contamination in seafood, despite viruses being leading causes of foodborne illness worldwide.
Rodrigues: A case study in food safety challenges
The outer island of Rodrigues, often called the “Cinderella of the Mascarene Islands,” depends heavily on fishing and seafood processing for local livelihoods. The island specializes in producing dried octopus and salted fish at a small-scale, cottage industry level.
Yet, research revealed that these products often have quite high levels of bacteria, indicating relatively poor hygiene and sanitation practices during processing. This highlights how crucial proper training and facilities are for food safety.
Varying enforcement of best practices
Mauritius has a thriving tuna export industry, sending canned and pouched tuna to Europe and frozen tuna loins to the United States. These exports are a major source of income for the island’s ocean economy. Companies targeting international markets follow strict European Union standards and implement comprehensive food safety systems to meet export requirements. Unfortunately, seafood sold locally often lacks these same rigorous safety measures
The path forward: Closing the safety gap
Taken together, the ocean surrounding the Republic of Mauritius provides food security and economic opportunity. Yet, it is important that seafood intended for local markets adhere to equally rigorous safe and hygienic handling practices as exported products to ensure consumer protection. As food handlers play a pivotal role in ensuring the safety of food along the food chain from sea to plate, there is a need to ensure that they receive proper and adequate training. It is also important to note that the current food regulations of Mauritius need to be reviewed to not only be more risk-based but also include microbiological standards for other agents of foodborne illness such as foodborne viruses.
Main photo from Freepik
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