Comparison of the effects of a commercial and an autochthonous Pediococcus acidilactici and Staphylococcus vitulus starter culture on the sensory and safety properties of a traditional Iberian dry‐fermented sausage “salchichón”

The effect of the addition of an autochthonous starter culture and commercial starter culture on the physico‐chemical and sensory characteristics of the dry‐fermented sausage ‘salchichon’ was investigated. Sausages were prepared with a mixture of Pediococcus acidilactici MC184 and Staphylococcus vitulus RS34 as the autochthonous starter culture (P184S34), ripened for 86 days, and compared with a commercial starter batch (CS1). Strains of acid lactic bacteria and Staphylococcus were identified in the samples along the ripening process which demonstrated that the inoculation of sausages assures their implantation during the ripening process. However, P184S34 starter culture showed a higher inhibitory effect on enterobacteria and coliform flora than the CS1 batches, guaranteeing a better quality hygienic sausages. Dry‐fermented sausages ripened with P184S34 showed higher amounts of NPN and volatile compounds derived from amino acid catabolism than the CS1 batches. Especially important was the result found in biogenic amines, since the P184S34 reduced their accumulation compared to the commercial starter batch. The inoculation of a decarboxylase‐negative autochthonous starter culture P184S34 reduced the biogenic amine accumulation guaranteeing safety and homogeneity of the products without producing a negative effect on the sensory characteristics of the traditional fermented sausages.     

Survival of Escherichia coli O157:H7, nitrite content and sensory acceptance of low‐salt Chinese paocai fermented by screened lactic acid bacteria

Starter cultures of low‐salt Chinese paocai were screened from 135 lactic acid bacteria (LAB) by evaluating their antimicrobial activity and growth characteristics. Furthermore, the survival of Escherichia coli O157:H7, nitrite contents and sensory acceptability of the starter‐fermented paocai were evaluated. LAB BC92, which was identified as Lactobacillus pentosus, was used as a starter culture to produce paocai. In comparison with naturally fermented paocai, the disappearance time of E. coli O157:H7 in starter‐fermented paocai decreased from 5.29 to 3.82 days, and the maximum nitrite content decreased from 11.73 to 8.64 mg kg^?1, and the nitrite reduction time decreased from 4 to 3 days. In addition, starter fermentations were able to accelerate the flavour formation and shorten the paocai ripening period. The paocai that was fermented naturally and fermented by BC92 all had good sensory acceptance, and no significant difference (P > 0.05) was observed.     

Stimulation of Cadaverine Production by Foodborne Pathogens in the Presence of Lactobacillus,Lactococcus, and Streptococcus spp.

Abstract: The effect of Lactobacillus plantarum (FI8595), Lactococcus lactis subsp. cremoris MG 1363), Lactococcus lactis subsp. lactis (IL 1403), and Streptococcus thermophilus on cadaverine and other biogenic amine production by foodborne pathogens was investigated lysine decarboxylase broth. Both of lactic acid bacteria and foodborne pathogens used (especially Staphylococcus aureus, E. coli, Lc. lactis subsp. lactis and Lb. plantarum) had an ability to convert aminoacids into biogenic amine. The conversion of lysine into cadaverine was the highest (167.11 mg/L) by Lactobacillus spp. Gram‐positive bacteria generally had a greater ability to produce cadaverine with corresponding value of 46.26, 53.76, and 154.54 mg/L for Enterococcus faecalis, S. aureus, and Listeria monocytogenes, respectively. Significant variations on biogenic amine production were observed in the presence of lactic acid bacteria strains (P < 0.05). The role of lactic acid bacteria on biogenic amine production by foodborne pathogens varied depending on strains and specific amine. Cadaverine accumulation by Enterobactericeae was increased in the presence of lactic acid bacteria strains except for St. thermophilus, which induced 2‐fold lower cadaverine production by S. Paratyphi A. Lc. lactis subsp. lactis and Lc. lactis subsp. cremoris induced 10‐fold higher increases in histamine for E. coli and K. pneumoniae, respectively. Lactic acid bacteria resulted in strong increases in cadaverine production by P. aeruginosa, although remarkable decreases were observed for histamine, spermidine, dopamine, agmatine, and TMA in the presence of lactic acid bacteria in lysine decarboxylase broth . The result of the study showed that amine positive lactic acid bacteria strains in fermented food led to significant amine accumulation by contaminant bacteria and their accumulation in food product may be controlled by the use of proper starters with amine‐negative activity. Practical Application: Foodborne pathogens and certain lactic acid bacteria are particularly active in the production of biogenic amines. Most of the strains of bacteria possess more than 1 amino acid decarboxylase activity under lysine enrichment culture conditions. Lactic acid bacteria strains had a significant role on increase putrescine accumulation by foodborne pathogens. The increased production of biogenic amines in mixed culture is the result of presence of amine positive lactic acid bacteria strains. The addition of a proper selected starter culture with amine‐negative activity is advisable to produce safer fermented food with low contents of biogenic amines.     

Application of Autochthonous Mixed Starter for Controlled Kedong Sufu Fermentation in Pilot Plant Tests

Traditional sufu is fermented by back‐slopping and back‐slopping has many defects. The objective of this study was to apply autochthonous mixed starter to control Kedong sufu fermentation. Sufu was manufactured using back‐slopping (batch A) and autochthonous mixed starter (batch B) with Kocuria kristinae F7, Micrococcus luteus KDF1, and Staphylococcus carnosus KDFR1676. Considering physicochemical properties of sufu, 150‐day sufu samples from batch A and 90‐day sufu samples from batch B met the standard requirements, respectively. Considering sensory characteristics of sufu, 150‐day sufu samples from batch A and 90‐day sufu samples from batch B showed no significant differences (P > 0.05). The maturation period of sufu was shortened by 60 d. Profiles of free amino acids and peptides partly revealed the mechanism of typical sensory quality and shorter ripening time of sufu manufactured by autochthonous mixed starter. In final products, content of total biogenic amines was reduced by 48%. Autochthonous mixed starter performed better than back‐slopping. Fermentation had a positive influence on the quality, safety, and sensory properties of sufu. The application of autochthonous mixed starter does not change the sensory characteristics of traditional fermented sufu. In addition, it reduces maturation period and improves their homogeneity and safety. It is possible to substitute autochthonous mixed starter for back‐slopping in the manufacture of sufu.     

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     

Suitability of selected autochthonous lactic acid bacteria cultures for Pecorino Sardo Dolce cheese manufacturing: influence on microbial composition,nutritional value and sensory attributes

The use of an autochthonous starter culture made up by Streptococcus thermophilus, Lactococcus lactis subsp. lactis, Lactobacillus plantarum and Lactobacillus casei in the production of experimental Pecorino Sardo Dolce PDO resulted in a high presence of presumptive mesophilic lactococci and lactobacilli, ~10 log colony‐forming units (cfu), and in significantly higher amount of total free amino acids and free fatty acids, 195.1 vs 178.9 and 328.6 vs 191.8 mg/100 g of experimental vs control cheese (made using a commercial starter) respectively. The experimental cheese also displayed better sensory properties such as taste and aftertaste.     

传统发酵与接种发酵酸肉安全品质特性的分析

本实验对4种不同地区传统发酵酸肉的食用安全性进行分析,并进一步以植物乳杆菌120（Lp-120）、酿酒酵母2018（Sc-2018）、木糖葡萄球菌135（Sx-135）为发酵剂,研究不同发酵剂对发酵酸肉安全性的影响。采用高效液相色谱法、分光光度法、滴定法分别对酸肉生物胺、亚硝酸盐、过氧化值进行检测分析。研究结果表明:苗家酸肉、包谷酸肉、榕江酸肉和黎平酸肉的生物胺总含量分别为961.20、4673.85、3201.97和4687.37 mg·kg?1,除苗家酸肉外,其他地区生物胺含量均超过限定标准（1000 mg·kg?1）。另外,包谷酸肉、黎平酸肉的过氧化值也较高,分别达到0.181、0.158 g·(100 g)?1。但是,4种传统酸肉中亚硝酸盐残留量均在3.3~4.4 mg·kg?1范围内,未超过限量标准（30 mg·kg?1）。研究发现,接种Lp-120、Sc-2018以及混合发酵剂能显著（P<0.05）降低生物胺含量;接种Lp-120和Sc-2018的酸肉过氧化值分别为0.0377、0.0433 g·(100 g)?1,比包谷酸肉和黎平酸肉低70%左右;四组接种发酵（混合发酵组、Lp-120、Sc-2018、Sx-135）的亚硝酸盐含量均明显低于传统发酵组,其中,Sc-2018组最低,达到2.129 mg·kg?1。此外,接种发酵和传统发酵酸肉均有较好的微生物安全性。总体来看,不同地区的传统酸肉品质存在差异,包谷酸肉、榕江酸肉和黎平酸肉存在生物胺安全问题。接种发酵（混合发酵、Lp-120、Sc-2018）可明显提高酸肉的食用安全性。     

Malolactic fermentation of Tempranillo wine: contribution of the lactic acid bacteria inoculation to sensory quality and chemical composition

Malolactic fermentation (MLF) of Tempranillo Rioja wines (Spain) inoculated with two lactic acid bacteria (LAB) strains were studied and compared with spontaneous MLF. Inoculation with selected Oenococcus oeni lyophila shortened MLF duration up to 19 days and lead to wines with more fresh and fruity characters, especially when implantation was 100%. We demonstrated modifications in the concentration of volatile and nitrogenous compounds and a good correlation between analytical and sensory attributes was also noted. In addition, the low initial amino acid concentration and the consumption of these compounds by the inoculated yeast strain during alcoholic fermentation resulted in wines with very low biogenic amines levels (under 3.75 mg L^?1) after MLF and 3 month storage period in all cases. The results showed the significance of choose the most suitable starter to elaborate quality wines and suggest the control of amino acid content in must and wine to prevent the formation of biogenic amines.     

Improvement of Fermented Chinese Cabbage Characteristics by Selected Starter Cultures

Traditional fermented vegetables have inconsistent quality and high nitrite content, whereas a commercial starter culture could overcome these problems. A total of 34 lactic acid bacteria strains were screened from 2 homemade naturally fermented Chinese cabbages. Fermented characters of single starter or mixed cultures were examined, including acidification, growth rate, and nitrite depletion ability in the fermented culture. As a result, the combined starter culture (Lactobacillus delbrueckii IWQ and Lactobacillus paracasei J21) was selected. The fermented Chinese cabbage resulted from this mixed starter culture had higher sugar content residue (30.5 mg/mL for mixed culture and 22 mg/mL for control). And the titratable acid of the cabbage fermented by the mixed starter was 110°T, which was twice higher than that of control sample. The selected starter culture also had a better texture and sensory qualities than that the starter cultures from a local fermented Chinese cabbage plant, especially for its significantly lower nitrite content (3.00 mg/kg for mixed culture and 4.49 mg/kg for control). The findings of this study form a database for further studies on the development of starter cultures for fermented cabbage production and could replaced the local plant starter culture.     

康普茶直投式发酵剂的制备及其发酵性能的研究

目的 制备菌种成分明确的康普茶直投式发酵剂,并对直投式发酵剂的发酵性能进行探究,解析直投式发酵剂应用于康普茶生产的理论基础。方法 通过测定菌株存活率筛选适用于发酵康普茶的巴氏醋杆菌、木醋杆菌、拜耳结合酵母的冻干保护剂,再将冻干后的菌粉接种至红茶中发酵,以前期开发的康普茶混菌发酵剂为对照,通过测定康普茶发酵过程中糖类、乙醇、有机酸和感官等指标考察直投式发酵剂的发酵性能。结果 巴氏醋杆菌、木醋杆菌、拜耳结合酵母的最优冻干保护剂分别为30 g/100 mL的菊粉、20 g/100 mL的海藻糖、30 g/100 mL的海藻糖,存活率分别为92.41±1.33%、57.61±2.29%、52.95±1.67%。在康普茶发酵过程中,直投式发酵剂与未冻干的混菌发酵剂发酵的康普茶在主要成分、电子舌评测及感官评定等各个方面均呈现相似的变化趋势。直投式发酵剂发酵后的康普茶中以酸味柔和兼具健康功效的葡萄糖酸和葡萄糖醛酸为主,醋酸仅在第二天检测到;在发酵终点康普茶的乙醇含量符合饮料的标准（< 0.5% m/V）。结论 直投式发酵剂与实验室前期获得的混菌发酵剂发酵的康普茶品质相当,可以为康普茶直投式发酵剂的制备提供理论和技术支持。     

Effect of fermentation with mixed starter cultures on biogenic amines in bighead carp surimi

The effects of one group mixed starter cultures, combined with Lactobacillus casei, Streptococcus lactis, Saccharomyces cerevisiae Hansen, and Monascus anka, and a batch without starter as control on biogenic amines accumulation in the bighead carp surimi during fermentation were investigated. Determination of five different biogenic amines was carried out by reverse‐phase high‐performance liquid chromatography with UV detection. Results showed that mixed starter cultures decreased the pH quickly from initial pH value of 6.4 to 5.2, inhibited the growth of contaminant microorganisms, such as Enterobacteriaceae and Pseudomonas, present in the raw materials, and suppressed the accumulation of histamine, tyramines, spermine and spermidine. Fermentation inoculated with combination of Lactobacillus casei, Streptococcus lactis, Saccharomyces cerevisiae Hansen, and Monascus anka with negative‐decarboxylase activity may prevent biogenic amine formation in the fermented ssurimi and improve hygienic quality of fermented surimi.     

Effect of Lactobacillus plantarum on the survival of acid‐tolerant non‐O157 Shiga toxin‐producing E. coli (STEC) strains in fermented goat's milk

The ability of goat's milk fermented with a Lactobacillus plantarum strain B411, and in combination with commercial starter culture, to inhibit acid‐adapted (AA) and non‐acid‐adapted (NAA) environmental non‐O157 STEC strains was investigated. Acid‐adapted and NAA non‐O157 STEC strains were not inhibited in the L. plantarum‐fermented goat's milk, while the goat's milk fermented with the combination of L. plantarum and starter culture inhibited AA more than NAA non‐O157 STEC strains. Environmental acid‐tolerant non‐O157 STEC strains were not inhibited by L. plantarum, starter culture or combination of starter culture with L. plantarum unless they were subjected to prior acid adaptation such as backslopping.     

Effectiveness of a Lactobacillus sakei starter culture in the reduction of biogenic amine accumulation as a function of the raw material quality

The effectiveness of an amine-negative starter culture (Lactobacillus sakei CTC494) in the reduction of biogenic amine production during the ripening of fermented sausages was examined. Four batches were manufactured in parallel: spontaneously fermented and starter-mediated sausages were manufactured from two lots of raw materials of different hygienic quality. Besides the biogenic amine contents, changes in the microbial counts, nitrogenous fractions, pH, and water content were measured at several sampling points during the ripening process. In sausages manufactured from good quality meat, the starter strain of L. sakei reduced and even inhibited biogenic amine accumulation during sausage fermentation, the end products showing extremely low biogenic amine contents (tyramine levels less than 15 mg/kg of dry matter and putrescine and cadaverine levels less than 5 mg/kg of dry matter). Nevertheless, starter-mediated sausages made from poorer-quality raw materials showed much higher amine contents (308, 223, and 36 mg/kg of dry matter of cadaverine, tyramine, and putrescine, respectively), which were only slightly lower than those of the spontaneously fermented sausages made from the same raw materials. The relatively high bacterial numbers of raw materials of poorer-hygienic quality diminished the beneficial effect of the starter strain. Therefore, the effectiveness of the starter was strongly dependent on the hygienic quality of the raw materials used.     

四川区域自然发酵香肠及人工接种牦牛肉发酵香肠中生物胺含量的研究

以四川省10 区域自然发酵香肠及人工接种发酵剂的牦牛肉香肠共21 个样品为研究对象,测定发酵香肠中的生物胺含量。结果发现,21 个发酵香肠样品中均检测到酪胺、亚精胺、精胺、尸胺、腐胺、色胺及组胺,β-苯乙胺均未检出;生物胺总量在57.34～411.12 mg/kg,除采自凉山州西昌的自然发酵牦牛肉香肠和广安的自然发酵猪肉香肠中酪胺含量超过了美国食品及药品管理局（Food and Drug Administration,FDA）规定标准（酪胺含量≤100 mg/kg）,其余均不存在生物胺安全问题。     

Safety and functional aspects of pre‐selected pediococci for probiotic use in Iberian dry‐fermented sausages

The purpose of this study was to investigate pre‐selected pediococci for potential probiotic use in Iberian dry‐fermented sausages. A total of twelve strains isolated from Iberian dry‐fermented sausages and pig faeces were evaluated according to safety and functional characteristics including biogenic amines and d ‐lactic acid production, antibiotic susceptibility, cell adhesion and antimicrobial activity against food‐borne pathogens. The strain P. acidilactici SP979 was able to establish itself and compete with enteropathogens such as Salmonella choleraesuis on the intestinal epithelium and an inhibition of such pathogenic bacteria as Listeria monocytogenes and Staphylococcus aureus in vitro. This strain was also considered safe to be used with regard to its void aminogenic potential, low d ‐lactic acid production and antibiotic resistance pattern; being identified as a potential probiotic meat starter culture suitable for manufacture of dry‐fermented Iberian sausages.     

Effect of milk fat replacement by polyunsaturated fatty acids on the microbiological,rheological and sensorial properties of fermented milks

A modified milk (W3DD) where fat had been replaced by oils enriched in ω‐3 polyunsaturated fatty acids was used for the manufacture of a set‐type fermented product. In order to improve the organoleptic properties of the product, 30 g l^?1 whey protein concentrate (WPC) was added during the manufacturing process. Samples were fermented employing a commercial probiotic starter culture (ABT‐2), which contained Streptococcus thermophilus ST‐20Y, Lactobacillus acidophilus LA‐5 and Bifidobacterium lactis BB‐12. The acidification process was dependent on the WPC addition, which favoured the increase of viable counts, but fermentation was not influenced by the milk fat composition. The highest counts of the probiotic strains, L acidophilus LA‐5 (3.3 × 10⁵ cfu g^?1) and B lactis BB‐12 (5.5 × 10⁷ cfu g^?1), after 21 days of storage at 4 °C, were found in fermented products derived from W3DD supplemented with WPC. Addition of WPC also increased the firmness of the products and reduced syneresis. No apparent colour changes due to fat composition or WPC supplementation were observed in the products. Milk fat replacement by oils rich in ω‐3 polyunsaturated fatty acids had a negative influence on the product texture but did not affect the typical yoghurt flavour. These defects were overcome by the addition of 30 g l^?1 WPC, which improved the appearance, texture and general acceptability scores in the product. Copyright © 2004 Society of Chemical Industry     

Reduced biogenic amine contents in sauerkraut via addition of selected lactic acid bacteria

The contents of free amino acids and biogenic amines in spontaneously fermented sauerkraut, inoculated or not with specific lactic acid bacterium strains, were monitored throughout 45 d of storage. The strains tested were Lactobacillus plantarum 2142, Lactobacillus casei subsp. casei 2763 and Lactobacillus curvatus 2771. In both the control and the experiments, the total amino acid contents increased with time – and the predominant ones were aspartic acid, arginine and glutamic acid. However, upon inoculation with either strain, the total biogenic amine contents remained considerably lower than those of the control (especially in the cases of L. casei subsp. casei and L. curvatus); every single biogenic amine was actually below the 100 ppm-threshold. The dominant biogenic amines in the control were putrescine – and tyramine and histamine, to a lesser extent; the putrescine content was 10-fold lower if inoculation had taken place with either lactobacillus tested; and histamine and tyramine were essentially absent during storage, whereas they ranked above 200 ppm in the control by 45 d. Hence, an efficient food-grade biological tool was made available that constrains buildup of dangerous biogenic amines in fermented vegetables during storage.     

Sensory Acceptability and Stability of Probiotic Microorganisms and Vitamin C in Fermented Acerola (Malpighia emarginata DC.) Ice Cream

ABSTRACT:  Six fermented acerola ice creams were produced, containing different starter cultures ( Bifidobacterium longum , Bi.lactis , and traditional yogurt starter culture— Streptococcus thermophilus and Lactobacillus delbrueckii spp. bulgaricus ) and final pH (5 and 4.5). The ice creams were evaluated for probiotic culture viability, vitamin C stability, and sensory acceptance. Mix fermentations were stopped when pH 5.0 and 5.5 were attained. However, after the addition of acerola pulp the determined pH were 4.5 and 5, respectively. Mixes were frozen and stored for 15 wk at −18 °C. The viable counts for probiotic cultures remained above the recommended minimum limit of 10⁶ cfu/g during 15 wk storage even in products with pH 4.5. Vitamin C concentration remained around 140 mg/100 g of product. The attributes of aroma, taste, texture, and overall acceptance obtained scores in the range of 5.15 to 7.22. The fermented acerola ice cream was a suitable food for the delivery of vitamin C and Bifidobacterium strains with excellent viability and acceptable sensory characteristics.     

Effect of starter cultures on the quality of Suan yu,a Chinese traditional fermented freshwater fish

The generation of volatile compounds of four starter cultures composed of isolated microorganisms from traditional Suan yu was investigated. The cultures included two pure starters (PS1: Lactobacillus plantarum 120 and PS2: Pediococcus pentosaceus 220) and two mixed starters (MS1: L. plantarum 120, Staphylococcus xylosus 135 and Saccharomyces cerevisiae 31 at 1:1:1; MS2: P. pentosaceus 220, S. xylosus 135 and S. cerevisiae 31 at 1:1:1). Naturally fermented Suan yu was used as control. The volatile compounds were collected from the headspace of the samples by Solid‐phase microextraction and analysed by gas chromatography–mass spectrometry. The type and total content of volatile compounds in the mixed‐starter‐fermented fish were higher than those of the pure‐starter‐fermented samples and control. A total of seventy nine and eighty volatile compounds were detected in Suan yu fermented with MS1 and MS2, respectively, with ethanol as the predominant compound and hexanal, ethyl acetate, 3‐methylbutanol, 3‐hydroxy‐2‐butanone, hexanoic acid ethyl ester and 2,3‐butanedione as the other compounds. Furthermore, the sensorial acceptance of the different products with mixed starter cultures seemed to improve the quality of Suan yu products.