Effect of starter culture and fermentation temperature on water mobility and distribution in fermented sausages and correlation to microbial safety studied by nuclear magnetic resonance relaxometry

Water mobility and distribution in fermented sausages produced with differences in pH development as a result of the use of three different starter cultures (T-SPX, F-1, or F-SC-111) and two fermentation temperatures (24 °C, or 32 °C) were studied using low-field proton NMR relaxometry. Changes in the distribution and mobility of water in fermented sausages upon fermentation and drying were detectable by NMR T₂ relaxation, and the progress in the drying process could be followed as a shift towards faster relaxation times. In addition, the distribution of water in the sausages was significantly affected by the pH decline. The sausages were spiked with Listeria monocytogenes, Salmonella, and Escherichia coli VTEC, and partial least squares regressions revealed that 90% of the variation in reduction of Salmonella and VTEC could be explained by the NMR T₂ relaxation decay. Consequently, the study demonstrated that NMR relaxometry is a promising technique for elucidating process parameters and microbial safety in the production of fermented meat products.     

Characterization of fermented silver carp sausages inoculated with mixed starter culture

To improve the characteristics and functionality, and increase the use of fish muscle, three groups mixed starter cultures (group one: Lactobacillus plantarum-15, Staphylococcus xylosus-12 and Pediococcus pentosaceus-ATCC33316 [S-PXP]; group two: Lactobacillus planatrum-15, Staphylococcus xylosus-12 and Lactobacillus casei subs casei-1.001 [S-PXC]; and group three: Staphylococcus xylosus-12, Lactobacillus casei subsp. casei-1.001 and P. pentosaceus-ATCC33316 [S-XCP]) were inoculated in minced silver carp muscle to produce a fermented fish product. During the 48 h fermentation at 30 °C, silver carp muscle inoculated with mixed starter cultures resulted in a rapid pH decrease, suppression in the increase of thiobarturic acid (TBARS) values, total volatile base nitrogen (TVB-N), trimethylamine (TMA), and the growth of spoilage bacteria and pathogens, and had higher whiteness than the control (without any starter) (P<0.05). The changes in SDS-PAGE indicated extensive hydrolysis of muscle protein occurred during fermentation. This study showed that the mixed starter cultures could substantially improve the flavor, digestibility, and nutritional value of the silver carp muscle.     

Changes in biogenic amine levels during storage of Mexican-style soft and Spanish-style dry-ripened sausages with different aw values under modified atmosphere

Two raw sausages were prepared: a soft and a dry-ripened one, both by local traditional and industrial manufacturing practices. Sausages were packaged under a CO₂/N₂ atmosphere at different targeted activity water (a_w) values: 0.96 and 0.92 (soft sausages) and 0.88 and 0.82 (dry-ripened sausages). Sausages were then stored at 5 °C for 42 days or at 12 °C for 240 days (soft and a dry-ripened sausages, respectively). The time-related changes in dominant microbiota, pH and biogenic amine contents during storage were determined. Tyramine was the most abundant biogenic amine in all the sausages. Biogenic amine levels were higher in dry-ripened sausages than in soft sausages at packaging. However, during refrigerated storage soft sausages were fermented and the levels of biogenic amines increased (P < 0.05). At the end of storage, traditional soft sausages with 0.96 a_w presented comparable levels of biogenic amines to traditional dry-ripened sausages.     

Fermentation of bighead carp (Aristichthys nobilis) surimi and the characteristics of fermented bighead carp surimi products

BACKGROUND: To improve the properties and functionality of bighead carp (Aristichthys nobilis) muscle, bighead carp surimi was inoculated with combinations of Saccharomyces cerevisiae, Lactobacillus and Monascus and fermented, and then bighead carp sausages were prepared. The characteristics of fermented bighead carp surimi and sausages were investigated. RESULTS: During the 24 h fermentation at 30 °C, bighead carp surimi inoculated with mixed starter cultures resulted in a rapid decrease of pH, and suppression in the growth of Enterobacteria. The bighead carp sausages exhibited better colour, taste, flavour and appearance than the control (P < 0.05). The changes in non‐protein nitrogen (NPN), free amino acid in the fermented bighead carp surimi and SDS–PAGE patterns indicated that severe hydrolysis of muscle protein had occurred during fermentation. The sausages inoculated with the mixed starter cultures gained higher scores for flavour and overall acceptability than the control. CONCLUSIONS: The characteristic of fermented bighead carp surimi and sausages can be significantly improved by fermentation with the combinations of yeast, Lactobacillus and Monascus. Copyright © 2008 Society of Chemical Industry     

Physical and chemical changes of silver carp sausages during fermentation with Pediococcus pentosaceus

Changes in protein composition and physicochemical properties of silver carp sausages during fermentation were investigated. As fermentation progressed, the amount of salt-soluble and water-soluble proteins decreased gradually with a concomitant increase in insoluble proteins and non-protein constituents. The rapid reduction in pH to 4.5 within 48 h of fermentation coincided with a progressive increase in titratable acidity. The increasing content of TCA-soluble peptides during fermentation indicated intensive degradation of muscle proteins. SDS–PAGE showed that muscle proteins tended to aggregate into large polymers through disulphide bonds and non-disulphide covalent bonds during fermentation, which may be responsible for the formation of superior textural properties of silver carp sausages.     

Novel starter cultures to inhibit biogenic amines accumulation during fish sauce fermentation

Bacteria with amine oxidase activity have become a particular interest to reduce biogenic amines concentration in food products such as meat and fish sausages. However, little information is available regarding the application of these bacteria in fish sauce. Hence, our study was aimed to investigate the effect of such starter cultures in reducing biogenic amines accumulation during fish sauce fermentation. Staphylococcus carnosus FS19 and Bacillus amyloliquefaciens FS05 isolated from fish sauce which possess amine oxidase activity were used as starter cultures in this study. Fermentation was held for 120 days at 35 °C. The pH value increased in all samples, while salt concentration remained constant throughout fermentation. Aerobic bacteria count was significantly lower (p < 0.05) in the control than in inoculated samples as a result of starter cultures addition. However, it decreased during fermentation due to the growth inhibition by high salt concentration. Proteolytic bacterial count decreased during fermentation with no significant difference (p > 0.05) among samples. These bacteria hydrolyzed protein in anchovy to produce free amino acid precursors for amines formation by decarboxylase bacteria. The presence of biogenic amines producing bacteria in this study was considered to be indigenous from raw material or contamination during fermentation, since our cultures were negative histamine producers. Amino acid histidine, arginine, lysine and tyrosine concentration decreased at different rates during fermentation as they were converted into their respective amines. In general, biogenic amines concentration namely histamine, putrescine, cadaverine and tyramine increased throughout fermentation. However, their concentrations were markedly higher (p < 0.05) in the control (without starter cultures) as compared to the samples treated with starter cultures. Histamine concentration was reduced by 27.7% and 15.4% by Staphylococcus carnosus FS19 and Bacillus amyloliquefaciens FS05, respectively. Both cultures could also reduce other amines during fermentation. After 120 days of fermentation, the overall biogenic amines concentration was 15.9% and 12.5% less in samples inoculated with Staphylococcus carnosus FS19 and Bacillus amyloliquefaciens FS05, respectively, as compared to control samples. These findings emphasized that application of starter cultures with amines oxidase activity in fish sauce fermentation was found to be effective in reducing biogenic amines accumulation.     

Biogenic amine formation in Nham,a Thai fermented sausage,and the reduction by commercial starter culture, Lactobacillus plantarum BCC 9546

Biogenic amines are of concern for sausage due to their toxicological effects on nervous, blood pressure, gastric and intestinal systems. In this study, the influence of raw pork meat quality and starter culture inoculation on biogenic amines accumulation in Nham, a Thai traditional fermented pork, were studied. Before Nham processing, pork meat was stored at 30 °C for 6 h, and at 4 and −20 °C for 2 days. Formation of biogenic amines (cadaverine, putrescine, histamine and tyramine) was significantly higher in Nham processed from stored meat. Accumulation of these biogenic amines in Nham reduced significantly by the addition of Lactobacillus plantarum BCC 9546, a commercial Nham starter culture. The results highlight the importance of using fresh meat products and the inclusion of an appropriate starter culture to minimise the formation of biogenic amines during the process of Nham fermentation.     

Adaptation of Escherichia coli O157:H7 to acid in traditional and commercial goat milk amasi

Acid resistance of Escherichia coli O157:H7 strains UT 10 and UT 15 were determined in traditional Amasi fermented for 3 days at ambient temperature (ca 30 °C) and commercial Amasi fermented at 30 °C for 24 h and stored at 7 °C for 2 days. Escherichia coli O157:H7 counts in commercial Amasi were detected at 2.7 log₁₀ cfu/ml after 3 days while those in traditional Amasi could not be detected after the same period. There was no significant difference (p ? 0.05) in the survival of acid adapted (AA) and non-adapted (NA) E. coli O157:H7 in traditional Amasi, while in commercial Amasi, the NA strain survived significantly (p ? 0.05) better than its AA counterpart. Regardless of prior adaptation to acid, E. coli O157:H7 can survive during fermentation and storage of fermented goat milk Amasi. Also, the fermentation time, pH and storage temperature affects the survival of E. coli O157:H7 in the fermented milk.     

Technological conditions influence aminogenesis during spontaneous sausage fermentation

The influence of two manufacturing processes on biogenic amine formation during the manufacture of Spanish dry fermented sausages of different diameters (fuet and llonganissa) was evaluated to elucidate which conditions allow better control of the aminogenic activity of spontaneous microbiota. Technological conditions affected both the amounts and the qualitative profile of biogenic amine accumulated. The higher processing temperature and relative humidity in process A (simulating those applied in industrial manufacture) favoured aminogenesis, since biogenic amine accumulation was faster and higher than in sausages manufactured under the process B (close to those used in traditional practices). The major amine differed depending on the diameter of the sausages, tyramine being the major amine in fuet (2.5 cm diameter sausage), and putrescine in llonganissa (4.5 cm). Moreover, sausages of higher diameter (llonganissa) had higher biogenic amine contents compared with the thinnest sausages (fuet). Conditions would modulate biogenic amine accumulation not only due to its influence on development of the bacterial population but also on its aminogenic activity. From the biogenic amine point of view, when sausages are spontaneously fermented, traditional lower temperatures and relative humidities are more appropriate than those usually applied in industrial processes.     

Improvement of the quality and abatement of the biogenic amines of grass carp muscles by fermentation using mixed cultures

BACKGROUND: To improve the quality of processed grass carp (Ctenopharyngodon idellus) products and control the accumulation of hazardous substances therein, minced grass carp slices were salted for 6 h at room temperature and then inoculated with mixed starter cultures of Lactobacillus casei, Streptococcus lactis, Saccharomyces cerevisiae Hansen and Monascus anka and fermented for 12 h at 30 °C. The changes in some characteristics and biogenic amine contents of the fermented muscles were investigated. RESULTS: During the 12 h fermentation at 30 °C, muscles inoculated with mixed starter cultures showed a rapid decrease in pH from 6.0 to 5.1 and suppression of the growth of enterobacteria and pseudomonads. The fermented muscles exhibited better colour, appearance, flavour and overall acceptability than the control (P < 0.05). The changes in non‐protein nitrogen and free amino acid contents of the fermented muscles and in their sodium dodecyl sulfate polyacrylamide gel electrophoresis profiles indicated that severe hydrolysis of muscle proteins occurred during fermentation. The accumulation of biogenic amines in the muscles was efficiently reduced by fermentation with mixed starter cultures. CONCLUSION: Fermentation with mixed starter cultures of L. casei, S. lactis, S. cerevisiae Hansen and M. anka significantly improved the characteristics of grass carp muscles and controlled the accumulation of biogenic amines. Copyright © 2009 Society of Chemical Industry     

Impact of fermentation conditions and refrigerated storage on microbial quality and biogenic amine content of sauerkraut

White cabbage (Brassica oleracea L. var. capitata cv. Bronco) was fermented, at 0.5% and 1.5% NaCl, using Lactobacillus plantarum or Leuconostoc mesenteroides as starter cultures and, subsequently, sauerkraut was stored at 4 °C for 3 months. Microbial populations and six biogenic amines (putrescine, cadaverine, histamine, tyramine, spermine and spermidine) were investigated. Fermentation and storage increased aerobic mesophilic bacteria and LAB populations in sauerkrauts, and this was accompanied by a rise in biogenic amine content. L. plantarum sauerkrauts produced with 0.5% NaCl had the highest microbial counts, whilst no differences between salt contents were found with L. mesenteroides. Total biogenic amine amount was lower at 0.5% NaCl than at 1.5% in both induced fermentations and L. mesenteroides produced a lower content than did L. plantarum. Spermidine was the major contributor to the total biogenic amine content, followed by putrescine, whilst histamine was present at the lowest level. The individual and total biogenic amine levels in the experimental sauerkrauts stored at 4 °C for 3 months were below the upper limits reported in the literature for fermented products, indicating good quality and safety of the sauerkrauts. L. mesenteroides starter and 0.5% NaCl were the optimal fermentation conditions for producing sauerkrauts with the lowest biogenic amine contents.     

Dabsyl derivatisation as an alternative for dansylation in the detection of biogenic amines in fermented meat products by reversed phase high performance liquid chromatography

The commonly applied HPLC method to determine biogenic amines in dry fermented meat after dansylation was compared with an alternative dabsylation procedure. The use of dabsyl chloride at 70 °C resulted in a 25-min reduction of the derivatisation time, in comparison with the dansylation at 40 °C. Furthermore, the use of irritating ammonia to remove the excess of dansyl chloride can be avoided. Introduction of the SPE cleaning procedure on the C18 cartridge resulted in a reliable and sensitive method of biogenic amines determination in a complex protein–fat matrix, which is typical of dry fermented sausages.     

Influence of technological conditions of sausage fermentation on the aminogenic activity of L. curvatus CTC273

The influence of technological factors (temperature and relative humidity of the manufacturing process and the diameter of the sausage) on the aminogenic activity of the strain Lactobacillus curvatus CTC273 was evaluated. Inoculation of sausages with L. curvatus CTC273 resulted in the accumulation of large amounts of biogenic amines (higher than 1000 mg/kg dry matter in some samples) during the manufacture of fuet and llonganissa sausages. Sausages produced via process ‘A’ (3 days at 20-23 °C and 90-95% RH followed by 20 days at 12-14 °C and 70% RH) contained significantly higher amounts (p < 0.05) of biogenic amines than those manufactured via process ‘B’ (23 days at 12-13 °C and 70-90% RH), specifically tyramine, cadaverine and phenylethylamine in llonganissa and phenylethylamine in fuet. The higher fermentation temperature and relative humidity during the fermentation stage in process ‘A’ promoted decarboxylase activity in L. curvatus CTC273 and thus favoured amine accumulation. The diameter of the sausages also influenced biogenic amine production. Higher amine levels were found (p < 0.05) in llonganissa than in fuet, regardless of the manufacturing conditions. The effect of the factors considered on the modulation of aminogenic activity is not necessarily linked to the effect of strain growth, but chiefly favouring proteolytic and decarboxylase reactions.     

Proteolytic activity of Saccharomyces cerevisiae strains associated with Italian dry-fermented sausages in a model system

Strains of Saccharomyces cerevisiae isolated from Italian salami were screened for proteolytic activity in a model system containing sarcoplasmic (SMS) or myofibrillar (MMS) proteins, at 20 °C for 14 days, to evaluate the possible influence on the proteolysis of fermented sausages.SDS-PAGE revealed that 14 of the most osmotolerant strains were responsible for the extensive hydrolysis of the main myofibrillar proteins, while only one strain was able to hydrolyze sarcoplasmic proteins. Free amino acids (FAA) accumulated during proteolysis were strain-dependent with different patterns from sarcoplasmic or myofibrillar protein fraction. In general, proteolysis lead Cys, Glu, Lys and Val as the most abundant FAA in the inoculated MMS samples. Volatile compound analysis, determined by SPME-GC-MS, evidenced 3-methyl butanol in MMS, and 2-methyl propanol and 3-methyl-1-butanol in SMS as major compounds. Our findings highlight that S. cerevisiae could influence the composition in amino acids and volatile compounds in fermented sausages, with a strain-dependent activity.     

Potential production and preservation of dahi by Lactococcus lactis W8, a nisin-producing strain

Lactococcus lactis W8 produced nisin concomitantly while fermenting milk to “dahi”, a traditional Indian fermented milk. The activity of nisin was detected at 3 h of fermentation, which increased in parallel to growth of the organism and reached its maximum at 6 h. The activity remained essentially stable thereafter. At 7 h of fermentation of milk with the strain L. lactis W8 the pH of the medium dropped to 4.2, when the milk became converted to dahi. The produced dahi displayed antibacterial property against spoilage and pathogenic bacteria including Listeria monocytogenes. When L. monocytogenes was mixed with dahi at 5.2 log CFU/ml and stored at 4 °C, the number of L. monocytogenes gradually decreased and became undetectable at 10 h. L. lactis W8 appeared to be a suitable starter culture for production of dahi from milk and preservation of the dahi.     

Probiotic beverage from cashew apple juice fermented with Lactobacillus casei

This study optimized the conditions of Lactobacillus casei NRRL B-442 cultivation in cashew apple juice, as well as, determined the proper inoculum amount and fermentation time. Moreover, it was investigated the survivability ability of L. casei in cashew apple juice during refrigerated storage (4 °C) for 42 days. The optimum conditions for probiotic cashew apple juice production were initial pH 6.4, fermentation temperature of 30 °C, inoculation level of 7.48 Log CFU/mL (L. casei) and 16 h of fermentation process. It was observed that the L. casei grew during the refrigerated storage. Viable cell counts were higher than 8.00 Log CFU/mL throughout the storage period (42 days). The values of lightness, yellowness and total color change increased and the values of redness reduced along the fermentation and refrigerated storage periods. The fermented juice with L. casei is a good and healthy alternative functional food containing probiotics. Cashew apple juice showed to be as efficient as dairy products for L. casei growth.     

Quality characteristics of Dutch-style fermented sausages manufactured with partial replacement of pork back-fat with pure, pre-emulsified or encapsulated fish oil

Dutch-style fermented sausages were manufactured with 15% and 30% pork back-fat substitution by pure or commercial encapsulated fish oil, either added as such or as pre-emulsified mixture with soy protein isolate. Adding commercial encapsulated fish oil was the most important factor influencing the chemical composition. The fat content was not significantly different between products (p > 0.05). The n−6/n−3 ratio decreased from 8.49 in controls to 0.90-2.47 in modified products. Lipid oxidation parameters (propanal and hexanal) showed much higher values for sausages with pure fish oil than for products with encapsulated oil. For the latter, lipid oxidation was similar to controls. Products with encapsulated or pre-emulsified oil were significantly firmer than products from other treatments in physical and sensory analysis (p < 0.05). Overall, it is technologically feasible to enrich dry fermented sausages with n−3 fatty acids from fish oil and the application of commercial encapsulated fish oil seems to be the best in retaining overall quality.     

Polyphenols and antioxidant capacity of Phaseolus vulgaris stored under extreme conditions and processed

Phaseolus vulgaris is a foodstuff that not only supplies nutrients, but also bioactive compounds with antioxidant capacity; however, bad post-harvest storage or processing can diminish the antioxidant capacity. In this work, the effect of storage under extreme conditions, of thermal processing and of fermentation on the content of phenolic compounds and their antioxidant capacity (AA) in beans of just harvested P. vulgaris were evaluated. Combination of temperatures of 30 and 50 °C and relative humidity of 11% and 80% for 150 days were evaluated. Extreme storage conditions drastically decreased the AA, demonstrating that post-harvest storage at low temperature and humidity preserves the antioxidant capacity of the beans. Regarding processing, cooking decreased the scavenging effect and the AA by 63.5% and 56.8%, while fermentation decreased them by only 14% and 22%, respectively. It was concluded that the loss of antioxidant capacity due to heating is less in fermented beans.     

Sugar metabolism and involvement of enzymes in sugarcane (Saccharum officinarum L.) stems during storage

Sugarcane (Saccharum officinarum L. cv. Badila) was harvested at the mature stage and stored at 2, 10, and 20 °C for 30, 90, and 120 days, respectively. Metabolic changes in the contents of sucrose and reducing sugar in relation to the activities of soluble acid invertase (SAI), neutral invertase (NI) and sucrose-phosphate synthase (SPS), in sugarcane juice, were studied. Extractable juice, sucrose and vitamin C declined significantly with increasing storage temperatures, while respiration rate increased. There was a rapid increase in titratable acidity during storage, with a more rapid rate at higher temperatures. A sharp increase in reducing sugar was observed within 20 days at 20 °C and 70 days at 10 °C, followed by a rapid decrease. Both SAI and NI activities showed a sharp increase within 15 days at 20 °C, followed by a rapid decrease, while a moderate increase occurred within 40–60 days at 10 °C. Slight increases were observed in SPS activity within 20 days at 20 °C and 50 days at 10 °C. Enzyme activities remained steady or underwent a small change in canes stored at 2 °C. Enzyme activities were significantly correlated with reducing sugar content.