Determination of histamine levels in long-tail tuna (Thunnus tonggol) stored at different temperature

Abstract

Histidine is precursor for histamine (4-(2-aminoethyl) imidazole) formation through a process called decarboxylation with the aid of histidine decarboxylase enzyme possessed by particular bacterial species. Since storage temperature is highly influenced the formation of histamine, a study regarding histamine and bacterial count was conducted. Longtail tuna was stored at -20, 4, 15, 25 and 37 C and analysis of bacteria and histamine was done for every 48 hours till reaching 196 hours for freezing and chilling storage temperature. Histamine determination and bacterial count was taken for every 0, 6, 12,18 and 24 hours for 15, 25 and 37 C. At 0 day of storage for -20̊ C, gut and non gut fish samples showed histamine level of 3.496 mg/100. Reduction of histamine levels took place after 48 hours of storage but increased later throughout the storage period up to 8 days, reaching a value of 4.84 and 3.78 mg/100 g for gut and non gut tuna, respectively. Similar trend of result was seen at 4 C where a gradual increase of histamine concentration was observed throughout the storage period. However, the histamine level in gut tuna exceeded the safety level at day 8. At temperature 15 and 25 C, the gut fish meat is not safe for consumption at 24 hours. Meanwhile, the safety limit can be seen within 12 hours and 18 hours of storage in gut and non gut fish stored at 37 C, respectively. For bacterial cell enumeration, at -20 C, the initial count of bacteria is 5.4 Log CFU/g for both fish condition. The count then slightly increased to 6.28 and 5.91 for gutted and non gutted respectively at 48 hours till reaching last storage time. Similar trend was recorded at 4, 15, 25 and 37 C from time to time. However, bacterial count is largely seen at 37 C. This may be due to the presence of spoilage bacteria that can deteriorate the quality of fish.

Tracking spoilage bacteria in the tuna microbiome

“…DNA quality and quantity were assessed by spectrophotometry (NanoDrop ® , Wilmington, DE, USA). The V3-V4 region of the 16S rDNA gene was amplified using universal bacterial primers modified for Illumina sequencing: 343F (5'-ACGGRAGGCAGCAG) (Economou et al 2007;Guizani et al 2005;Hungerford 2021;Mahusain et al 2017) and 784R (5'-TACCAGGGTATCTAATCCT) (Andersson et al 2008). The reaction mixture consisted of 12.5 μL of 2X Phusion Mix (New England Biolabs ® , Ipswich, MA, USA), 1 μL of each primer at 10 μM (Eurofin ® , Luxembourg), 10 ng of DNA template and enough molecular-grade H 2 O (Qiagen ® ) to reach a final volume of 25 μL.…”

“…Histamine is produced by specific SSOs (Gram & Dalgaard 2002;Jørgensen et al 2000) called histamine-producing bacteria (HPB), from a precursor amino acid (histidine) present in high concentrations in Scombridae, that HPB catalyse with the enzyme histidine decarboxylase (HDC) (Prester 2011). It has been clearly established that storage temperature is a major factor influencing the production of histamine by HPB (Economou et al 2007;Guizani et al 2005;Hungerford 2021;Mahusain et al 2017;Silva et al 1998). Yet, while these histamineproducing bacteria have been identified and the production mechanisms of this biogenic amine are relatively well known, the ecology and development of HPB within the postmortem microbiome of tuna remain poorly understood.…”

Efek Suhu dan Waktu Simpan terhadap Kualitas Bagian Tengah Yellowfin Tuna Segar (Thunnus albacares)

“…Korelasi antara kandungan histamin dan bau sering tidak konsisten, seperti pembentukan histamin tanpa signifikan bau (FAO/WHO, 2012) dan terdeteksi bau tanpa peningkatan histamin (Du et al, 2002). Kandungan histamine dan Mikroba gutted Tuna lebih tinggi dari pada non-gutted yang disimpan dalam beberapa temperatur dikarenakan jumlah bakteri lebih tinggi pada bagian isi perut dibandingkan bagian lainnya (Mahusain et al, 2016). Penelitian dilakukan untuk mengetahui pengaruh suhu dan lama penyimpanan terhadap pembentukan histamin, total bakteri dan sensori bau pada bagian tengah Tuna sirip kuning.…”