Reduction of biogenic amine and nitrite production in low-salt Paocai by controlled package during storage: A study comparing vacuum and aerobic package with conventional salt solution package

Incorporation of hydrogen-producing magnesium into minced beef meat protects the quality attributes and safety of the product during cold storage

The impact of hydrogen (H2) producing magnesium (Mg) incorporation into minced beef meat (MBM) on the quality and safety of the product was investigated. The H2-producing Mg (H2-P-Mg)-incorporated MBMs were vacuumed (VP) and stored at 4 °C for 12 days. Other MBMs were vacuumed and gassed with H2 or N2. At the end of storage, the lowest browning index values were for H2 and H2-P-Mg samples. H2- PMg and VP methods generally decreased the counts of mesophilic and psychrotrophic bacteria and yeast molds and restricted the formation of thiobarbituric acid reactive substances and biogenic amines. Heat mapping, PCA, and multivariate analysis methods confirmed chemical analysis results. The volatile compounds were at their highest levels in the control samples at the end of storage, followed by H2, N2, H2-P-Mg, and VP samples. Using the H2-P-Mg method in MBM preparation could protect the quality characteristics and safety of the product during cold storage.

Culture condition optimization of naturally lacto-fermented cucumbers based on changes in detrimental and functional ingredients

A two-step trial was used to optimize the culture condition of naturally lacto-fermented cucumbers. In the first trial, changes in pH values and total biogenic amines were measured to optimize the pickling juice formula. A 15% crystal sugar solution with low-salt brine at 4 °C was proved to be the best formula. In the second trial, pH values, organic acids, total phenolics, flavonoids, saponins and free amino acids, as well as biogenic amines and nitrites under the optimal pickling formula were measured. The optimal fermentation day was suggested at around 8 days. During the cucumber's fermentation process, the pH value was quickly lowered to <4.6. Meanwhile, the functional ingredients increased significantly. In contrast, total biogenic amines and nitrites did not exceed the risk limit, evidencing the safety and functional characteristics for the naturally lacto-fermented cucumbers. The two-step trial has evidenced the possibility to develop desirable lacto-fermented cucumbers.

Novel strategies for controlling nitrite content in prepared dishes: Current status, potential benefits, limitations and future challenges

Sodium nitrite is commonly used as a multifunctional curing ingredient in the processing of prepared dishes, especially meat products, to impart unique color, flavor and to prolong the shelf life of such products. However, the use of sodium nitrite in the meat industry has been controversial due to potential health risks. Finding suitable substitutes for sodium nitrite and controlling nitrite residue have been a major challenge faced by the meat processing industry. This paper summarizes possible factors affecting the variation of nitrite content in the processing of prepared dishes. New strategies for controlling nitrite residues in meat dishes, including natural pre-converted nitrite, plant extracts, irradiation, non-thermal plasma and high hydrostatic pressure (HHP), are discussed in detail. The advantages and limitations of these strategies are also summarized. Raw materials, cooking techniques, packaging methods, and storage conditions all affect the content of nitrite in the prepared dishes. The use of vegetable pre-conversion nitrite and the addition of plant extracts can help reduce nitrite residues in meat products and meet the consumer demand for clean labeled meat products. Atmospheric pressure plasma, as a non-thermal pasteurization and curing process, is a promising meat processing technology. HHP has good bactericidal effect and is suitable for hurdle technology to limit the amount of sodium nitrite added. This review is intended to provide insights for the control of nitrite in the modern production of prepared dishes.

Reduced formation of biogenic amines in low-salt Zhacai via fermentation under CO2-modified atmosphere

Reducing sodium salt content in traditional fermented vegetables and developing low-salt fermented products have attracted increasing attention.However, low-salt fermented vegetables are prone to accumulate toxic biogenic amines (BAs) caused by the undesirable metabolism of spoilage microorganisms. This study aimed to investigate the impact of a CO₂-modified atmosphere (MA) approach to the fermentation of low-salt Zhacai and the accumulation of BAs. The results show CO₂-MA effectively suppressed the production of excessive BAs in low-salt Zhacai, as evidenced by a decrease in the total BA content from 63.66 to 161.41 mg/ kg under natural air conditions to 1.88-24.76 mg/ kg under CO₂-MA. Overall, the mechanism of hindering BA formation was closely related to the change in the microbial community and the downregulation of BA-producing enzymes. Lactic acid bacteria, including Lactiplantibacillus plantarum, Weissella spp., and Pediococcus spp., were enriched under CO₂-MA, whereas amine-producing microorganisms (e.g., Halomonas spp., Psychrobacter spp., Corynebacterium spp., and Levilactobacillus brevis) were greatly inhibited. Moreover, metagenomic analysis revealed that genes encoding amino acid decarboxylase, amine deiminase, and amine synthase were downregulated, which could be the fundamental reason for BA reduction. This study provides an alternative method for reducing BA production in fermented food.

Bacterial Diversity of Sun-Dried Spanish Mackerel in Dalian and Application of Lactobacillus plantarum X23 as a Biopreservative

ABSTRACT

Sun-dried Spanish mackerel is a common food in Dalian and made by adding salt and sun drying, which has special physical, chemical, and microbiological properties. In this study, the physicochemical properties and microbial composition of commercially available sun-dried Spanish mackerel in Dalian were assessed, and some Lactobacillus strains were screened as a biopreservative for sun-dried Spanish mackerel preparation. The results showed that the total volatile base nitrogen content in the traditional sun-dried Spanish mackerel samples from Dalian was within 30 mg/100 g, the histamine content was 7 to 17 mg/kg, and the dominant bacteria at the genus level were Lactobacillus, Psychrobacter, and Ralstonia. A strain with biopreservative potential was isolated from a sun-dried Spanish mackerel sample, identified as L. plantarum species by 16S rDNA sequencing, and assigned as L. plantarum X23. Fresh Spanish mackerel flesh was treated with 16% brine and L. plantarum X23 at a dose of 107 CFU/mL and then dried in the sun. The sun-dried Spanish mackerel flesh treated with 16% brine and L. plantarum X23 showed a decreased histamine and acid value, increased free amino acid content, and a higher sensory score compared with the sun-dried Spanish mackerel without L. plantarum X23 treatment (P < 0.05). In conclusion, the sun-dried Spanish mackerel purchased from the supermarkets in Dalian were safely edible, and L. plantarum X23 can significantly reduce the content of histamine and putrescine in self-made, low-salt, sun-dried Spanish mackerel and has potential as a biopreservative for sun-dried Spanish mackerel preparation.

HIGHLIGHTS

Determination of 6 biogenic amines in food using high-performance liquid chromatography-tandem mass spectrometry without derivatization

A rapid and simple method for the determination of 6 biogenic amines (BAs) in food was established on HPLC-MS /MS without derivatization. Samples were extracted with 5% perchloric acid and cleaned with n-hexane for lipid removal. The analytes were separated on Waters XBridge® HILIC (150 mm × 2.1 mm, 3.5 µm) and analyzed with multiple-reaction monitoring (MRM) mode after positive electrospray ionization on HPLC-MS/MS. Good linearity with high correlation coefficient was obtained between 10-1000 µg/L for cadaverine (CAD), putrescine (PUT), tyramine (TYR) and 2-phenylethylamine (2-PHE) and between 1-100 µg/L for histamine (HIS) and tryptamine (TRY), with the detection limits of the method ranging from 0.1 mg/kg for HIS and TRY, and 1.0 mg/kg for CAD, PUT, TYR and 2-PHE, which are under the residue limit of Chinese regulation. Spiking experiments demonstrated good recoveries between 70.2-114.6%, with relative standard deviations (RSDs) between 0.44-13.01%. This method was validated for BAs determination in liquor, fermented meat products, vegetable products, soybean products, dairy products, seafood and its derived products. These results promise high feasibility for BAs monitoring in various food with easy-to-operate and fast sample preparation process, stable analysis on HPLC-MS/MS without derivatization.

Determination of 8 biogenic amines in aquatic products and their derived products by high-performance liquid chromatography-tandem mass spectrometry without derivatization

A method for the determination of 8 biogenic amines in aquatic products and their derived products was established by HPLC-MS/MS without derivatization. The samples were extracted by 5% perchloric acid solution. N-hexane was used to clean the extract. The analytes were separated by a column of ACQUITY UPLC HSS T3 (100 mm × 2.1 mm, 1.8 µm), and gradient eluted with a mixed solution of (0.5% formic acid) and acetonitrile. Good linearity was obtained with correlation coefficients (R²) >0.99. This method achieved higher sensitivity (from 0.1 mg/kg for tyramine, 2-phenylethylamine and tryptamine to 1.0 mg/kg for spermidine, spermine, cadaverin, histamine and putrescine). The average recoveries were demonstrated in the range of 70.9%-113.1%, with relative standard deviations (RSDs) from 0.33% to 10.81%. This method was suitable for the detection of BAs in aquatic products and their products.