Histamine, putrescine cadaverine and cis-urocanic acid (UCA) have all been implicated or suggested in scombroid fish poisoning. However, there is little information on UCA especially during storage. Changes in their contents during storage of whole Indian mackerel at 0, 3±1, 10±1 for up to 15 days and 23±2°C for up to 2 days were monitored. Fresh muscles contained 14.83 mg/kg trans-UCA, 2.23 mg/kg cis-UCA and 1.86 mg/kg cadaverine. Histamine and putrescine were not detected. After 15 days at 0 and 3°C, trans-UCA content increased to 52.83 and 189.51 mg/kg, respectively, and decreased to <2 mg/kg at the other two temperatures. Storage at 10°C also resulted in an increase in trans-UCA after 3 days, only to decrease after 6 days. The concentration of cis-UCA increased nearly 13-fold after 15 days at 0 and 3°C, decreased at 10°C and remained unchanged at 23°C. Histamine, putrescine and cadaverine levels increased significantly (P value<0.05) at all temperatures especially at 23°C.
The profile of total volatile base nitrogen (TVBN), pH, biogenic amines were studied in Indian mackerel packed under different levels of CO2. Gutted and beheaded Indian mackerel was stored in air, vacuum packaging (VP), 30% CO2/65% N2/5% O2 (M30C), 60% CO2/35%N2/5%O2 (M60C), 80% CO2/15%N2/5% O2 (M80C) and 100% CO2 (M100C) at 5°C for 12 days. The application of VP and MAP was effective in retarding the formation of TVBN, total biogenic amines and improve the shelf life of Indian mackerel. Cadaverine obtained the best correlation with storage time when compared with other biogenic amines. Cadaverine or cadaverine + putrescine can serve as a reliable objective freshness indicator of fish stored in different atmospheres. Among the commonly used freshness indices, TVBN was the best quality indicator correlated with histamine. VP and MAP conditions influenced the performance of quality indicators. pH was a good quality indicator of spoilage in air-stored fish except for VP and MAP packed fish. Lower value of TVBN (30 mg/100g) was suggested as an upper limit for this species of fish under MAP condition based on APC and sensory result.
Scombroid fish poisoning is usually associated with consumption of fish containing high levels of histamine. However, reports indicate that some cases have responded to antihistamine therapy while ingested histamine levels in these cases were low. Potentiation of histamine toxicity by some biogenic amines, and release of endogenous histamine by other compounds such as cis-urocanic acid (UCA) are some hypotheses that have been put forth to explain this anomaly. Very little is known about the effects of storage conditions on the production of both UCA isomers and biogenic amines in tuna. Thus, the production of trans- and cis-UCA, histamine, putrescine, and cadaverine in tuna during 15 d of storage at 0, 3, and 10 °C and 2 d storage at ambient temperature were monitored. The initial trans- and cis-UCA contents in fresh tuna were 2.90 and 1.47 mg/kg, respectively, whereas the levels of putrescine and cadaverine were less than 2 mg/kg, and histamine was not detected. The highest levels of trans- and cis-UCA were obtained during 15 d storage at 3 °C (23.74 and 21.79 mg/kg, respectively) while the highest concentrations of histamine (2796 mg/kg), putrescine (220.32 mg/kg) and cadaverine (1045.20 mg/kg) were obtained during storage at room temperature, 10 and 10 °C, respectively. Histamine content increased considerably during storage at 10 °C whereas trans- and cis-UCA contents changed slightly. The initial trans-UCA content decreased during storage at ambient temperature. Thus, unlike histamine, concentrations of trans- and cis-UCA did not result in elevated levels during storage of tuna.
Microbiological quality analysis of freshwater prawns from three sampling sites in Peninsular Malaysia viz: Site 1- Kg. Jumbang, Negri Sembilan; Site 2- Kg. Cangkat Tin, Perak and Site 3- Kg. Cenderiang, Perak for total mesophilic and psychrophilic aerobic counts, proteolytic bacterial counts, histamine producing bacteria, cadaverine producing bacteria and putrescine producing bacteria in the prawns and pond water for the three sites showed that the microbiological quality of freshwater prawns is related to the microflora of pond water in which they were grown. The initial bacterial counts indicated the values were in the range of log 4+ CFU/g for all samples. Total mesophilic and psychrophilic counts of the head regions were higher than that of the body regions for all prawn samples and types of growth media tested. All samples showed an increase in counts with time and temperature of storage up to log 7+ CFU/g for mesophilic counts after 12 hours at ambient, 6 days at 10 ± 2°C and 12 days at iced storage. The samples from Site 2 had relatively higher counts compared to the other two sites which correlated well with the levels determined in the pond water. Similar trends were observed for psychrophilic counts but at lower values for the different types of media studied.
Effects of preservatives on quality changes and shelf life of shrimp during iced storage indicated that boric acid, lactic acid and sodium metabisulphite managed to inhibit psychrophilic bacteria and biogenic amines formation in prawns while maintaining the mesophilic counts at lower levels during iced storage.
Biochemical analysis was carried out for pH profiles, freshness in terms of K-values, amino acids profiles, total volatile bases (TVB), total volatile acids (TVA) and biogenic amines for fresh and preserved Macrobrachium rosenbergii. Results showed that pH profiles of Macrobrachium rosenbergii explain the inability of this parameter to be used to evaluate the quality of Macrobrachium rosenbergii. Thus changes in pH profiles of Macrobrachium rosenbergii should be combined with indicators such as total volatile acids and total volatile bases. Total volatile acids of the shrimps increased steadily in small amounts throughout the storage period. A rapid increase in TVB at 100C was detected due to the increase in total aerobic bacteria at elevated temperatures. The microbial activities caused the decrease in the amino acids arginine, lysine and histidine which correlated well with the increase in the corresponding biogenic amines such as putrescine, cadaverine and histamine respectively. Preservatives used in this study controlled the production of these biogenic amines without significantly altering the pH of preserved shrimp.
The response patterns of microbial functional genes involved in biogeochemical cycles to cadaver decay is a central topic of recent environmental sciences. However, the response mechanisms and pathways of the functional genes associated with the carbon (C) and nitrogen (N) cycling to cadaveric substances such as cadaverine and putrescine remain unclear. This study explored the variation of functional genes associated with C fixation, C degradation and N cycling and their influencing factors under cadaverine, putrescine and mixed treatments. Our results showed only putrescine significantly increased the alpha diversity of C fixation genes, while reducing the alpha diversity of N cycling genes in sediment. For the C cycling, the mixed treatment significantly decreased the total abundance of reductive acetyl-CoA pathway genes (i.e., acsB and acsE) and lig gene linked to lignin degradation in water, while only significantly increasing the hydroxypropionate-hydroxybutylate cycle (i.e., accA) gene abundance in sediment. For the N cycling, mixed treatment significantly decreased the abundance of the nitrification (i.e., amoB), denitrification (i.e., nirS3) genes in water and the assimilation pathway gene (i.e., gdhA) in sediment. Environmental factors (i.e., total carbon and total nitrogen) were all negatively associated with the genes of C and N cycling. Therefore, cadaverine and putrescine exposure may inhibit the pathway in C fixation and N cycling, while promoting C degradation. These findings can offer some new insight for the management of amine pollution caused by animal cadavers.