A recent study conducted by researchers has shed light on significant geographic variability in allergenic protein profiles in black tiger shrimp (Penaeus monodon), one of the most widely farmed and consumed shrimp species globally. The findings, published in the International Journal of Molecular Sciences, underscore the potential implications for food safety assessments and allergen detection systems.

The study, led by Dorney et al. (2024), examined the impact of geographical origin on the major allergen tropomyosin and eleven other known crustacean allergens in black tiger shrimp. Sixty-three specimens were collected from farmed and wild-caught shrimp across three Australian states (Western Australia, New South Wales, and Queensland) and three Asian countries (China, India, and Indonesia). The researchers employed advanced techniques such as SDS-PAGE, immunoblotting, and mass spectrometry to analyze the protein composition of shrimp samples from these diverse locations.

A notable finding of the study was the considerable variability in the abundance of tropomyosin among shrimp from different origins. Tropomyosin, a heat-stable muscle protein, is a major allergen found in most crustaceans and is commonly targeted by commercial allergen detection systems. The study revealed that shrimp from India-farmed sources had the highest relative abundance of tropomyosin, nearly 13 times more than the lowest abundance found in Queensland-farmed shrimp. Additionally, shrimp from Australia generally exhibited lower levels of tropomyosin compared to those from other locations.

Moreover, the study highlighted differences in the abundance of other allergens, such as myosin light chain (MLC) proteins, sarcoplasmic calcium-binding protein, and hemocyanin. MLC-1 was predominantly found in China-farmed shrimp, while MLC-2 was most abundant in China-wild shrimp. These variations in allergenic proteins could have significant implications for allergen detection and food safety assessments, as current systems primarily target tropomyosin.

The study's findings emphasize the need for a nuanced approach to food allergen detection, considering geographic and environmental factors that may influence allergen expression. While the researchers did not collect data on environmental conditions such as temperature, salinity, and oxygen levels, they acknowledged that these factors could impact the expression of allergens in shrimp.

The authors also noted that genetic diversity between shrimp populations from different locations might contribute to the observed proteomic differences. Previous studies on single nucleotide polymorphisms (SNPs) and haplotype diversity support the notion of local adaptation among P. monodon populations in the Indo-Pacific region.

In light of these findings, the study calls for further research to explore the allergenicity of P. monodon from various locations using specific antibodies. Understanding whether these differences in allergen abundance affect allergenicity and food safety is crucial for improving detection systems and ensuring consumer safety.

The results of this study have significant implications for the seafood industry and regulatory bodies. Given the reliance on tropomyosin as a marker for crustacean allergens, the geographic variability in its abundance necessitates a re-evaluation of current detection methods. Ensuring accurate labeling and assessment of food allergens is vital for protecting consumers, particularly those with shellfish allergies, which can cause severe allergic reactions, including anaphylaxis.