This study aimed to investigate the influence of lipid oxidation intensity on histamine accumulation in fermented sausages and to identify specific lipid oxidation products potentially responsible for promoting histamine formation. Pork backfat was subjected to controlled oxidation at different temperatures to obtain varying degrees of oxidation and subsequently used in fermented sausage production. Histamine content was determined, and treatment groups exhibiting significant differences (50 °C, 60 °C, and 70 °C) were selected for further non-targeted metabolomic analysis. Multivariate statistical approaches, including PCA and OPLS-DA, were employed to screen and identify differential lipid oxidation products. The results revealed a significant positive correlation between the extent of lipid oxidation and histamine content (p < 0.05). Within the selected temperature range, the mean histamine contents were 22.97, 19.05, and 17.45 mg/kg for the 70 °C, 60 °C, and 50 °C treatments, respectively. A total of 33 lipid oxidation products were identified during ripening, predominantly aldehydes, ketones, alcohols, esters, acids, and alkanes. Pearson correlation analysis showed that four compounds—decanal, nonanal, hexanal, and 1-octen-3-ol—were strongly and positively correlated with histamine content (p < 0.01). These compounds were highlighted as key lipid-derived contributors potentially associated with elevated histamine levels. This study provides initial evidence that specific lipid oxidation products are closely linked to histamine accumulation in a real fermented sausage matrix. The findings offer a theoretical basis for reducing biogenic amine formation by controlling lipid oxidation during processing, which could have important practical implications for improving the safety of fermented meat products.

Morganella morganii, a strong histamine-producing bacterium (HPB), has been frequently detected in seafood, such as skipjack tuna. Temperature fluctuations and improper packaging have resulted in bacterial proliferation and histamine production. This study aimed to determine the effects of different packaging and temperature conditions on M. morganii growth and to examine histamine formation in skipjack tuna. A factorial design with two factors, namely packaging type (vacuum and non-vacuum) and storage temperature (4, 15, 30, and 40°C), was used in this study. The bacterial growth model over time was analyzed using DMFit software. Histamine production was analyzed using thin-layer chromatography (TLC) combined with ImageJ program visualization. The results indicated that different temperatures significantly affected the bacterial growth rate (p &lt; 0.05). The application of vacuum packaging at 4 °C retarded histamine formation in skipjack tuna cubes. The highest growth rate (0.2652 log CFU-1h-1) was observed in samples under non-vacuum packaging stored at 40 °C. M. morganii. At 15 °C, a 3 to 4 log increase was observed, starting from 3.2 to 7.5 (vacuum packaging) and from 5.8 to 8.3 log CFU-1 mL-1 (non-vacuum packaging) at the end. Nevertheless, the production of histamine in vacuum-packed samples stored at 15°C after days 3 and 4 of incubation were 446 ppm and 443.5 ppm, respectively. These findings highlight the importance of proper packaging of skipjack tuna using a cold chain system during storage. This study also confirmed the potential application of TLC for the detection of histidine and histamine.

Canned tuna is widely consumed worldwide due to its palatability, nutritional value, and convenience. However, it may pose a health risk to consumers if not properly processed or improperly handled and/or stored by consumers. This study evaluated the microbial safety and histamine content of canned tuna meat and the effect of the storage at different temperatures (4, 28, and 31 °C) for 7 days after opening on the microbial safety and histamine content. Data were analyzed by the SAS program. The aerobic bacteria counts in tuna samples after 48 hours of storage at 4 °C, 28 °C, and 31 °C were 3.2, 2.75, and 5.09 log CFU/g, respectively, with no significant difference observed between 4 °C and 28 °C (p &gt; 0.01). Similarly, the anaerobic bacteria counts were 3.3, 2.98, and 5.08 log CFU/g at 4 °C, 28 °C, and 31 °C, respectively, also showing no significant difference between 4 °C and 28 °C (p &gt; 0.01). Storage of canned meat at 4 °C showed more significant (p &lt; 0.01) microbial inhibition than storage at 28 °C, and 31 °C. No pathogenic bacteria were observed in all samples during storage at different temperatures. For the histamine test, the highest recorded concentrations were 3.53, 9.58, and 28.24 mg/kg in tuna samples stored at 4 °C, 28 °C, and 31 °C, respectively. The storage temperature influenced (p &lt; 0.01) histamine formation in tuna meat during storage. Recording histamine concentrations at zero time indicates that histamine was formed before opening the can, which may be due to failure to apply good hygiene practices in handling fish, as histamine does not degrade once formed. However, it did not exceed the maximum permissible limit. Also, the results of the microbial count and histamine content indicate that holding canned tuna meat after opening at 4 °C contributes to maintaining the safety of the tuna during storage.

Histamine (HIM) and tyramine (TYM) are among the most toxic biogenic amines (BAs) commonly found in various fermented soybean foods, yet the crucial BAs-producing strains are ignored. This study discussed and compared the effectiveness of two methods based on medium pH screening and target gene amplification for identifying HIM- and TYM-producing strains from two fermented soybean foods. The crucial strains responsible for HIM and TYM formation were identified and then characterized. It was found that the strains forming large amounts of total BAs promoted a high pH at the final medium, but there was no correlation between TYM/HIM formation and the pH value among the isolates. Furthermore, a large portion of isolates that produce TYM/HIM cannot be amplified. The hdc and tdc genes utilized reported universal pairs of primers, resulting in false negative results. Following two rounds of screening, most TYM/HIM-producing strains were found to belong to Bacillus. Bacillus cereus-HT-31-2 and Millerozyma farinosa-HT-42-1 were identified as crucial producers of TYM and HIM in soy sauce during the fermentation stage, while Proteus mirabilis-T-24-2 was found to be the key producer of TYM in thua nao. Moreover, the simulated medium was found to be beneficial for the formation of TYM/HIM by B. cereus-HT-31-2 and P. mirabilis-T-24-2, but not for M. farinosa-HT-42-1. The formation of TYM/HIM was not synchronized under different conditions. This study provides insights into the key strain responsible for the formation of HIM and TYM in fermented soybean foods.

Formation of urocanic acid versus histamine from histidine in chub mackerel (Scomber japonicus) fillets as determined by a mixed-mode HPLC method

Reduction of microbial contamination and biogenic amines formation in Ras cheese using Chlorella vulgaris extracts

Psychrotrophic Morganella spp. is a typical histamine producer commonly found in seafood, exhibiting a high histamine-producing capacity. In this study, two strains of Morganella (GWT 902 and GWT 904) isolated from yellowfin tuna were subjected to phenotypic and genotypic characterization. Phenotypic analysis reveals differences in growth temperature, NaCl tolerance, and D-galactose fermentation capacity between the two strains. Notably, the histamine production capacity of GWT 902 is significantly higher than that of GWT 904 at 4 °C. The complete genome sequences of strains GWT 902 and GWT 904 were sequenced, identifying GWT 902 as Morganella psychrotolerans and GWT 904 as Morganella morganii subsp. sibonii. Genomic analysis confirms the presence of histidine decarboxylase gene clusters (hdcT1, hdc, hdcT2, hisRS) in both strains, and sequence alignment shows that the amino acid sequence similarity of histidine decarboxylase encoded by the hdc gene was 95.24%. Gene function analysis further identified genes associated with putrescine biosynthesis, sulfur metabolism, lipase and protease secretion, and detected key genes in quorum sensing (QS), stress adaptation, and antibiotic resistance. This study provides valuable insights into the taxonomic analysis of psychrotrophic Morganella spp. and contributes to the development of efficient strategies for preventing histamine formation in seafood.

Pindang is a popular traditional fish product in Indonesia that has been produced for decades. Scombroid fish such as tuna, mackerel, and scad, which have a naturally high level of histidine, are commonly used to make pindang. Hence, improper handling and processing can lead to the accumulation of histamine, potentially causing health issues. Due to uncertainty or limited availability of fresh fish, many pindang producers use frozen fish as an alternative raw material. Reports implicate pindang as a major causative agent of HFP outbreaks in Indonesia. However, detailed investigation on how histamine is formed during pindang processing needs to be updated based on current processing conditions. This study investigated the existing practices of pindang production in Palabuhanratu, Sukabumi District, West Java Province, Indonesia; evaluated potential critical control points (CCPs) of histamine production; and identified strategies to improve the safety of pindang. Fresh Skipjack tuna (Katsuwonus pelamis) and frozen Eastern Little tuna (Euthynnus sp.) were used as raw materials for pindang processing. Results showed that pindang made from fresh fish generally had lower histamine levels compared to those made from frozen fish. Improper handling, especially abusive temperatures and time delays during fish thawing, was identified as the main causes of histamine formation during pindang processing. Therefore, to reduce the risk of histamine formation, a temperature-controlled circulated thawing system could be used. This finding can help pindang producers improve the safety of their products and ensure compliance with national and international food safety standards.

Inhibitory effects of κ-carrageenan oligosaccharides on histamine formation in Atlantic mackerel (Scomber scombrus) during cold storage

The formation of histamine in food is influenced by temperature, and histamine growth can be inhibited by maintaining a cold chain. However, simply relying on temperature control is insufficient, as certain bacteria can produce the enzyme histidine decarboxylase even at temperatures below 5°C. To address this issue, various methods, such as modified atmosphere packaging, high hydrostatic pressure, and irradiation, have been developed to control histamine in fishery products. However, these methods often require significant investments. Therefore, there is a need for a cost-effective solution to overcome this problem. This review explores a cost-effective solution through the utilization of bioactive compounds derived from underexplored seaweeds. Seaweed bioactive compounds, either in their pure form or as extracts, offer a promising alternative method to regulate histamine generation in fishery products due to their antibacterial activity, and this review provides comprehensive insights into the potential of different seaweed-derived bioactive compounds as inhibitors of histamine production, detailing their diverse applications in fishery products. It also explores the mechanism by which bioactive compounds prevent histamine formation by bacteria, focusing on the potential of seaweed bioactive compounds to inhibit bacterial histidine decarboxylase. Future trends in the inhibition of histidine decarboxylation are also discussed. The bioactive compounds considered, such as flavonoids, alkaloids, terpenes, and phenolic acids, exhibit their antibacterial effects through various mechanisms, including the inhibition of DNA and RNA synthesis, disruption of cytoplasmic and cell membranes, and inhibition of enzymes by reacting with sulfhydryl groups on proteins. In conclusion, the integration of underexplored seaweeds in fishery product preservation represents a promising and innovative approach for future food safety and sustainability.

Seventy-two qvevri wine samples from different regions of Georgia were studied for histamine and first ever results for Georgian qvevri wines were presented. Organoleptic analysis detected several wine faults that gave the possibility to search for correlation between elevated histamine contents and wine faults. Histamine content of the samples is presented according to the groups which were composed according to the tasting results and lactic/malic acid measurements. The influence of the activity of lactic acid bacteria (LAB) on the formation of histamine was clearly confirmed in the category of qvevri wines where Malolactic Fermentation (MLF) did not take place. Wines produced according to spontaneous MLF had higher histamine contents than the wines where MLF was induced by inoculated commercial LAB species but included low concentrations as well. This underlined the unpredictability to forecast histamine production by spontaneous MLF and confirmed the benefit of using commercial Oenococcus oeni LAB species for lower histamine accumulation in wines. Other categories represented wines where spontaneous MLF took place and contained one or more wine faults. Wines with “tourne” and lactic smell with elevated volatile acidity (VA) had higher levels of histamine but wines with mice flavour did not so. These results suggest that the ability of bacteria to cause some of the wine faults: “tourne”, lactic smell + elevated VA, might be associated with their ability to produce higher amounts of histamine as well.

The present work aimed to evaluate and mathematically model the effect of temperature on Morganella morganii growth and histamine formation in farmed mullet (Mugil cephalus) during refrigerated storage (at constant temperatures, T = 0, 2.5, 5, 10, and 15 °C) and to validate the developed models at non-constant temperature conditions (effective temperature Teff = 7.4 °C). Shelf life evaluation of chilled mullet was also carried out based on microbial spoilage, sensory degradation, and total volatile nitrogen (TVB-N) determination. Spoilage of mullet during refrigerated storage was co-dominated by Pseudomonas spp. and Enterobacteriaceae growth. Sensory rejection (score 5 for overall impression) and the end of shelf life coincided with a total microbial load of 8 log cfu/g. The shelf life of chilled mullet was estimated at 15, 11, 7, 3, and 1.5 days at 0, 2.5, 5, 10, and 15 °C, respectively. At T 0–5 °C, the time of sensory rejection coincided with TVB-N concentrations of 10.2–12.3 mg·100 g−1, and at 10–15 °C, the samples were sensorially rejected before TVB-N development. At storage temperatures &lt; 5 °C, sensory rejection was observed well before histamine levels reached a concentration of 50 mg/kg fish flesh. However, when abusive temperatures prevail, histamine should be considered as a risk factor for the human consumption of mullet.

Abstract Traditional fermented shrimp paste, locally known as terasi, is a popular food in Indonesia widely consumed owing to its distinctive flavor. Despite its ubiquity in traditional cuisines, terasi requires cautious consumption due to the presence of detrimental compounds associated with protein degradation and deteriorating quality. These compounds are generated during fermentation, including allergenic histamine and potentially carcinogenic acrylamide. This study aimed to improve the safety-related quality of terasi via the incorporation of black cumin (Nigella sativa) seed oil, which possesses potential antioxidant and anti-microbial activities. Supplementing shrimp paste with black cumin seed oil at concentrations of 2.5% (v/w) and 5% (v/w) significantly inhibited microbial growth, reduced lipid peroxidation, and mitigated the formation of histamine and acrylamide during fermentation for 30 days. Importantly, the inclusion of black cumin seed oil did not affect the sensory acceptance of shrimp paste, as evidenced by a sensory evaluation. Therefore, our findings suggest that black cumin seed oil could effectively enhance the safety-related quality parameters of shrimp paste, thus potentially serving as a beneficial adjunct ingredient.

Inhibitory potential of natural antimicrobial compounds against histamine-forming lactic acid bacteria

Terasi is a traditional fermented shrimp paste popularly consumed in Indonesia. Despite its widespread popularity and distinctive flavor, terasi consumption should be approached with caution due to the presence of harmful compounds linked to its degradation and declining quality. These compounds, including allergenic histamine and potentially carcinogenic acrylamide, form during the fermentation of terasi as a result of various chemical reactions and microbial activities. The objective of the current research was to enhance the safety and quality of shrimp paste by introducing Moringa oleifera leaves, locally known as daun kelor, that are rich in antioxidants and antimicrobial compounds. The supplementation of M. oleifera leaves (5%(w/w) and 10%(w/w)) significantly reduced microbial growth, lipid peroxidation, as well as the formation of histamine and acrylamide in terasi fermented for 30 days. Moreover, the inclusion of M. oleifera leaves did not alter the sensory acceptance of terasi. Consequently, this study suggests that M. oleifera leaves have the potential to serve as an adjunct ingredient, enhancing both the safety and overall quality of terasi.

This study aimed to verify the presence of biogenic amines (BAs) and evaluate the microbiological activity of some food samples collected from retail stores in the Kingdom of Saudi Arabia. A total of thirty-five dairy and fish products were collected and analyzed for BAs, including putrescine (PUT), cadaverine (CAD), spermidine (SPE), histamine (HIS), spermine (SPR), and tyramine (TYR), as well as for total colony count (TCC), lactic acid bacteria (LAB), Enterobacteriaceae, yeast and mold (Y and M), coliforms, and aerobic sporulation count (ASF). The thin layer chromatography (TLC) method was used in the analytical methodology to identify the BAs. The results showed the presence of BAs in all dairy products, but their concentration did not exceed the maximum permissible limit, which in contrast was established by the Food and Drug Administration (FDA) at 10 mg/100 g. The amounts of BAs in fish products varied significantly. All fish product samples contained levels of BAs below the permissible limit. Results of an independent study also indicated potential toxicity at levels of BAs (>10 mg/100 g) in Egyptian herring. Enterobacteriaceae and the coli group were present in higher concentrations in the Egyptian herring samples, whereas other samples (particularly frozen shrimp) showed increased TCC levels with a higher concentration of histamine-producing bacteria. From a consumer safety perspective, this study also indicated that food samples generally contained acceptable levels of BAs. In conclusion, there is a need to improve and standardize food quality and hygiene practices during production and storage to ensure human safety and prevent HIS formation.

Terasi, a traditional fermented shrimp paste from Indonesia, is commonly made from salted planktonic shrimp (Acetes japonicus) undergoing spontaneous lactic acid fermentation. In spite of its broad use and appreciated distinctive flavor, consuming terasi could be injurious for human consumption due to the presence of toxic compounds that are related to its deterioration and quality decrease, such as the allergenic histamine and probably carcinogenic acrylamide. These compounds are formed during fermentation of terasi due to a plethora of chemical reactions and microbial activities. This study aimed to improve the quality and safety of shrimp paste by incorporating during its fermentation torch ginger (Etlingera elatior) flowers, locally known as bunga kecombrang, that are rich in antioxidants and antimicrobial compounds. These flowers are widely utilized in Indonesian cuisine. The supplementation of torch ginger flowers (5%(w/w) and 10% (w/w)) significantly reduced microbial growth, lipid peroxidation, as well as the formation of histamine and acrylamide in terasi fermented over a period of 30 days. In addition, the supplementation of 10% torch ginger flowers improved the sensory acceptance of terasi. Therefore, this study suggests the potential of torch ginger flowers as an additional ingredient to improve the safety and quality of terasi.

To investigate the inhibitory impact of chlorogenic acid (CGA) on the growth of Morganella psychrotolerans and its ability to form histamine. The antimicrobial effect of CGA on M. psychrotolerans was evaluated using the minimum inhibitory concentration (MIC) method, revealing an MIC value of 10mg ml-1. The alkaline phosphatase (AKP) activity, cell membrane potential, and scanning electron microscopy images revealed that CGA treatment disrupted cell structure and cell membrane. Moreover, CGA treatment led to a dose-dependent decrease in crude histidine decarboxylase (HDC) activity and gene expression of histidine decarboxylase (hdc). Molecular docking analysis demonstrated that CGA interacted with HDC through hydrogen bonds. Furthermore, in situ investigation confirmed the efficacy of CGA in controlling the growth of M. psychrotolerans and significantly reducing histamine formation in raw tuna. CGA had good activity in controlling the growth of M. psychrotolerans and histamine formation.

Histamine (HIS) is primarily formed from decarboxylated histidine by certain bacteria with histidine decarboxylase (hdc) activity and is the most toxic biogenic amine. Hdc, which is encoded by the hdc gene, serves as a key enzyme that controls HIS production in bacteria. In this paper, we characterized the changes in microbial and biogenic amines content of traditional Sichuan-style sausage before and after storage and demonstrated that Enterobacteriaceae play an important role in the formation of HIS. To screen for Enterobacteriaceae with high levels of HIS production, we isolated strain RH3 which has a HIS production of 2.27mg/mL from sausages stored at 37°C for 180 days, using selective media and high-performance liquid chromatography. The strain RH3 can produce a high level of HIS after 28h of fermentation with a significant hysteresis. Analysis of the physicochemical factors revealed that RH3 still retained its ability to partially produce HIS in extreme environments with pH 3.5 and 10.0. In addition, RH3 exhibited excellent salt tolerance (6.0% NaCl and 1.0% NaNO2 ). Subsequently, RH3 was confirmed as Enterobacter hormaechei with hdc gene deletion by PCR, western blot, and whole-genome sequencing analysis. Furthermore, RH3 exhibited pathogenicity rate of 75.60% toward the organism, indicating that it was not a food-grade safe strain, and demonstrated a high level of conservation in intraspecific evolution. The results of this experiment provide a new reference for studying the mechanism of HIS formation in microorganisms. PRACTICAL APPLICATION: This study provides a new direction for investigating the mechanism of histamine (HIS) formation by microorganisms and provides new insights for further controlling HIS levels in meat products. Further research can control the key enzymes that form HIS to control HIS levels in food.

Nowadays, the customer's approach towards naturally preserved fish meat products has gained interest in overcoming the health risks of synthetic preservatives. So, our investigation aimed to study the effectiveness of natural preservatives for controlling histamine formation and spoilage in chilled shrimp. The potential of moringa extract (MOE), green tea extract (GTE), and olive leaf extract (OLE) (1.5% for each) to act as antioxidants in shrimp was evaluated. The histamine values recorded in the control group significantly differed from MOE, GTE, and OLE (p < 0.05) throughout the days of chilled storage. These findings emphasized the effect of the plant extracts to extend the shelf life of chilled shrimp and improve sensory attributes (color, odor, texture, and overall acceptability) and physicochemical characteristics (pH, TBA, and TMA) during a storage period of up to 14 days under refrigerated storage (4°C). These findings suggest that the extract, especially olive leaves, may serve as a food additive, extending the shelf life of shrimp.