Investigation of chemical preservatives in commercially available fish from Wayanad and Kannur Districts, Kerala, India

This study aims to assess the safety, quality, and consumer awareness of fish sold in local markets in the Kannur and Wayanad districts of Kerala, India, with a particular focus on the detection of harmful preservatives such as formaldehyde and ammonia. A total of 216 fish samples were collected for analysis, with 99 from 11 locations in Kannur and 117 from 13 locations in Wayanad. The primary species examined included sardines, Indian mackerel, and tuna. The results revealed varying levels of contamination across the samples, with ammonia detected in 3 out of 33 Indian mackerel, 5 out of 33 sardine, and 18 out of 33 tuna samples from Kannur. Similarly, ammonia was found in 8 out of 39 Indian mackerel and 27 out of 39 tuna samples in Wayanad, while no ammonia was detected in sardines. Formaldehyde contamination was also significant, with higher concentrations found in Indian mackerel and tuna samples. Notably, 7 out of 33 mackerel and 11 out of 33 tuna samples from Kannur, and 16 out of 39 mackerel and 15 out of 39 tuna samples from Wayanad tested positive for formaldehyde. The study highlighted the most prevalent contamination in tuna, with the highest ammonia presence in both regions. Formaldehyde contamination, a known carcinogen (IARC, 2006), was particularly concerning, especially in Indian mackerel, suggesting significant food safety risks. Additionally, a Quality Index Method (QIM) was used to evaluate the freshness and overall quality of the fish, revealing that improper handling, inadequate storage, and delayed transportation were key contributors to quality degradation. To assess the quality of fish, a one-way ANOVA was conducted to compare the quality of mackerel, sardine, and tuna samples from both districts. The analysis revealed statistically significant differences in the quality of fish across the three species in both Kannur (F (2, 30) = 7.63, p=0.002) and Wayanad (F (2, 36) = 6.06, p=0.005). Post hoc comparisons indicated that mackerel had significantly higher quality than sardines, but no significant difference was found between mackerel and tuna in both regions. Sardines were of significantly lower quality compared to tuna, both in terms of freshness and overall quality. A Google survey involving 75 participants (21 males, 54 females; age groups: 20-29, 30-39, 40-49, 50-59) investigated the adverse effects of consuming chemically preserved fish. Reported symptoms included stomach ache (9 females), vomiting (1 male, 4 females), nausea (1 male, 1 female), allergies (2 females), loose motion (2 females), itching (3 females), and throat pain (2 cases). These findings highlight a notable incidence of adverse reactions, particularly among female consumers, emphasizing the need for increased awareness and improved safety measures regarding the consumption of preserved fish products. A survey of 75 consumers across both districts explored purchasing habits, awareness of chemical preservatives, and trust in fish product labeling. The results indicated that local vendors and fish markets are the most common sources of fish, with a significant percentage of respondents expressing concerns about the use of harmful chemicals such as formaldehyde and ammonia in fish preservation. Consumer trust in product labeling was mixed, with 45.2% expressing confidence in the labels, while 42.5% felt that government regulations were insufficient to ensure fish quality. Furthermore, 87.7% of respondents expressed concern about the use of chemicals in fish farming, and 48.6% indicated a willingness to pay more for fish guaranteed to be of higher quality and free from harmful chemicals.