Influence of inoculation levels and processing parameters on the survival of Campylobacter jejuni in German style fermented turkey sausages

This study investigated the influence of inoculum levels and manufacturing methods on the survival of Campylobacter (C.) jejuni in raw fermented turkey sausages. Sausages were prepared and inoculated with C. jejuni. After inoculation, these sausages were processed and ripened for 8 days. Samples were taken throughout the ripening process. The presence of C. jejuni was established bacteriologically. Additionally, lactic acid bacteria were enumerated, pH values and water activity were measured to verify the ripening process. To detect changes in genotype and verify the identity of the recovered clones, AFLP analysis was carried out on the re-isolated strains. Whereas no C. jejuni were detectable when inoculating the sausages with the lowest inoculum (0.08-0.44 log(10) cfu/g sausage emulsion), C. jejuni were detectable for 12-24h by enrichment when inoculated with approximately 2 log(10) cfu/g. After inoculation with 4 and 6 log(10) cfu/g respectively, C. jejuni were detectable without enrichment for 12-48 h and by enrichment for 144 h at the most. The greatest decrease of the C. jejuni population occurred during the first 4 h of ripening. Only a very high inoculum level allowed the survival of the organism during a fermentation process and during ripening to pose a potential risk for consumers. Lower initial Campylobacter inoculums will be eliminated during proper ripening of the sausages, if sufficient decrease in water activity and pH-value is ensured.     

Lipid oxidation in n-3 fatty acid enriched Dutch style fermented sausages

Dutch style fermented sausages were manufactured with a substitution of 10%, 15% and 20% of pork backfat by flaxseed oil and canola oil, pre-emulsified with soy protein isolate. The 15% and 20% substitution were also reached by adding encapsulated flaxseed oil and encapsulated fish oil and by adding flaxseed oil, pre-emulsified with sodium caseinate, respectively. The products were sliced, packaged in an oxygen-enriched atmosphere and stored in the dark for 12 weeks at 7°C. No differences were detected in moisture, protein and fat content between control and modified sausages, with the exception of the formulation with sodium caseinate. The PUFA/SFA ratio increased from 0.30 in the control to 0.42-0.48 in the sausages with canola oil and to 0.49-0.71 in the sausages with flaxseed oil. The n-6/n-3 ratio decreased from 11.20 in the control to 6.94-5.12 in the sausages with canola oil and to 1.93-1.05 in the sausages with flaxseed oil. The addition of canola oil and encapsulated flaxseed oil resulted in a comparable shelf life as the control in terms of lipid oxidation. In the samples with addition of pre-emulsified flaxseed oil, especially with sodium caseinate, lipid oxidation clearly increased during storage. Physical and sensory analysis showed that the sausages with encapsulated fish oil and flaxseed oil resembled the control most.     

The effect of nisin on L. monocytogenes in Turkish fermented sausages (sucuks)

Turkish fermented sausage (sucuk) is a traditional, well-known meat product in Turkey. The aim of this study was to evaluate the effect of different nisin concentrations on Listeria monocytogenes in experimentally contaminated sucuk. Analyses were performed on at 0, 1, 3, 5, 7, 10, 15, 20, 25 and 30days for L. monocytogenes and other microbiological parameters (Total mesophilic aerobic bacteria and lactic acid bacteria) and physico-chemical parameters (pH, a(w) and moisture content).The sucuk dough was contaminated with L. monocytogenes ATCC 7644 at a concentration of 10(6)cfu/g, and the dough was divided into six equal groups. Each group was treated separately with different nisin concentrations (0, 5, 10, 25, 50 and 100μg/g). No L. monocytogenes surviving cells were detected in groups which contained 100μg/g and 50μg/g nisin at day 20 and 25, respectively (p<0.001). In conclusion, the inhibition of L. monocytogenes in sucuk increases with the increasing concentrations of nisin.     

Probiotics in fermented sausages

Probiotic foods receive market interest as health-promoting, functional foods. They have been introduced in a wide range of food industries. However, commercial application of probiotic microorganisms in fermented sausages is not common yet. There are both advantages and disadvantages connected to fermented meat matrices. They are adequate for the carriage of probiotic bacteria since they are usually not or only mildly heated and may promote the survival of probiotic bacteria in the gastrointestinal tract. In contrast, bacterial viability may be reduced due to the high content in curing salt and the low water activity and pH. Therefore, results are expected to be strain-dependent. Up till now, several approaches have been followed but most results are too preliminary to be able to evaluate the effect of probiotic fermented meats on human health. Candidate probiotic strains have been obtained through screening for technological requirements among bacteria that are naturally present in the meat or that originate from meat starter cultures. Alternatively, existing probiotic bacteria have been applied in meat products. Finally, the evaluation of the end-products needs to deal with both health effects and technological characteristics, for instance through human intervention studies and taste panels, respectively.     

The use of commercial starter cultures in the production of Turkish semi-dry fermented sausages

 The effects of three different starter cultures (Pediococcus acidilactici, Staphylococcus xylosus plus P. pentosaceus, S. carnosus plus Lactobacillus pentosus) were evaluated during the production of Turkish semi-dry fermented sausages. Sausages were studied during the fermentation phase, after heat processing and after drying for 24 h and 72 h. Chemical and organoleptical results indicated that in the processing of these semi-dry sausages a starter culture of P. acidilactici should be used. The use of this culture significantly reduced the pH, increased the lactic acid content and percentage of total heme pigments converted to the cured pigment and improved the development of the sausages' characteristics, i.e. color, appearance, flavor and general acceptability. Received: 20 February 1998 / Revised version: 7 May 1998     

Effect of processing conditions on the quality of naturally fermented Turkish sausages (sucuks)

Effects of temperature and different fat levels on the quality of Turkish sausages (sucuks) were studied during the ripening period. Sausage batters prepared at 10%, 20% and 30% fat levels were processed at 20-22 and 24-26 °C. A high ripening temperature and low fat level caused fast dehydration. Fat level affected water activity, colour, total viable and lactic acid bacteria counts of the sausages. Increasing fat content and ripening temperature resulted in high lightness (L*) and yellowness (b*) and low redness (a*) at the end of ripening. The sausages with 10% fat resulted in higher redness values. Growth of total viable and micrococci-staphylococci bacteria was affected by ripening temperature. Sausages ripened at 24-26 °C had a rapid increase in micrococci-staphylococci counts.     

Yeast populations on Spanish fermented sausages

Yeast populations on 24 lots of Spanish fermented sausages, made by four factories (F1, F2 and F4, artisanal; F3, industrial) were investigated throughout manufacture and the influence of different variables evaluated. In addition, 41 yeast strains were identified at the species level using two miniaturised systems: ATB32C (API System) and Vitek Yeast Biochemical Card (Vitek YBC). Levels of yeasts found in the sausage mixture (mean counts around 4 log units/g) were similar to those described by other authors. In sausages from factories F1 and F2, a further increase was noted, reaching 5.5 log units/g after fermentation. Counts subsequently decreased to 3.6 and 5 log units/g, respectively. In sausages from factories F3 and F4, decreasing counts were observed from the beginning, particularly in sausages from F3, where yeasts were almost absent in the finished product. Type of manufacture and sausage diameter, were the variables most influencing yeast counts. Debaryomyces hansenii (teleomorph of C. famata) was the dominant species, being found at all stages of manufacture. Trichosporon ovoides (formerly T. beigelii), Yarrowia lipolytica (perfect form of C. lipolytica), C. intermedia/curvata, C. parapsilosis, C. zeylanoides and Citeromyces matritensis (teleomorph of C. globosa) were also present. Direct identification was possible only with 50% of the total of strains investigated, although a higher number of strains was identified using the API than the Vitek YBC system.     

四川自然发酵香肠中组胺降解菌的筛选鉴定及初步应用

采用产生物胺显色培养基,从20个四川自然发酵香肠样品中共分离得到不产生物胺的菌株256株。以肉制品发酵剂相关标准作为初筛条件得到菌株17株,且对组胺均有不同程度的降解。对组胺降解率较高的5株菌的鉴定结果表明,19号、41号和46号分别为植物乳杆菌(Lactobacillus plantarum)、戊糖片球菌(Pediococcus pentosaceus)、混淆魏斯氏菌(Weissella confusa),47号和48号均为屎肠球菌(Enterococcus faecium)。19号、41号和46号菌株之间无明显拮抗作用,具有较好的生长能力和产酸能力,能耐受低温、低pH、60 g/L的食盐及150 mg/kg的亚硝酸盐,且混合菌株比单一菌株能更好地抑制产胺菌的生长。香肠成熟30 d时,接种组的组胺含量(46.56 mg/kg)比未接种组的组胺含量(66.77 mg/kg)降低了30.26%(p0.05)。研究结果表明,在发酵香肠生产中接种可降解组胺的乳酸菌,能有效降低产品中组胺含量,提高发酵香肠的食用安全性。     

The effect of different starter cultures and ripening temperatures on formation of biogenic amine in Turkish fermented sausages

Different starter culture added groups (Group I: Lactobacillus sake, Staphylococcus xylosus; Group II: Lactobacillus plantarum, Staphylococcus carnosus; Group III: Lactobacillus curvatus, Staphylococcus carnosus, and Staphylococcus xylosus) and control group sausage samples were produced experimentally at two different temperatures (22 and 26 °C). In raw materials and all groups, by the 0th, 2nd, 5th and 7th days of the ripening period, the analysis of HPLC and biogenic amine (tyramine, histamine, cadaverine, putrescine, phenylethylamine, tryptamine, spermine, and spermidine) amounts, microbiological (Lactic acid bacteria, Micrococcus/Staphylococcus, Enterobacteriaceae, Enterococcus spp., and moulds–yeasts) and chemical (pH, dry matter, and salt) have been done. During the ripening period, there is no statistical discrepancy (P > 0.05) in terms of biogenic amine amounts, microbiological, and chemical values detected from the sausage samples produced at 26 and 22 °C. However, in both levels of temperature, there is statistical discrepancy (P < 0.001) detected in terms of tyramine, putrescine values and the count of Enterococcus spp. between the starter culture added samples and control group samples. By this study, it has been stated that the ripening temperature does not make any statistical discrepancy (P > 0.05) for all values but the use of starter culture prevents the formation of biogenic amine in Turkish fermented sausages.     

Evaluation of antioxidative properties of Geranium macrorrhizum and Potentilla fruticosa extracts in Dutch style fermented sausages

Antioxidative properties of Geranium macrorrhizum, Potentilla fruticosa and Rosmarinus officinalis (as a reference) extracts were evaluated in Dutch style fermented sausages. Extracts were incorporated into sausages during preparation. The sausages were subsequently fermented, tested and compared to a standard spices mix, traditionally used for the production of such sausages. Formation of the primary oxidation products – peroxides, and secondary – TBARS and hexanal was monitored. The polar extracts from Potentilla showed some antioxidant activity, especially in combination with ascorbate, however the activity was low compared to the standard spices mix. Polar extracts from Geranium showed only negligible antioxidant activity.     

干发酵香肠中的生物胺

综述干发酵香肠中生物胺产生的条件,国外干发酵香肠中常见生物胺的种类及含量,与生物胺积累有关的微生物以及影响生物胺产生的理化因素,并提出了控制干发酵香肠中生物胺积累的措施。     

Short-chain fructooligosaccharides as potential functional ingredient in dry fermented sausages with different fat levels

The effects of short-chain fructooligosaccharides (sc-FOS) on colour, textural and sensory properties in dry fermented sausages have been studied. The sausages were manufactured with three different amounts of backfat (30%, 15% and 6%). The sc-FOS was incorporated in a sufficient amount to constitute 2%, 4% and 6% of the initial mixture. Physico-chemical parameters and microbiota evolution during ripening were not affected by the presence of this fibre. Colour parameters, especially lightness, decreased as the amount of sc-FOS incorporated increased. However, the presence of sc-FOS reduced hardness making the sausage easier to chew. Although all batches were well evaluated by the panellists, the higher acceptability was reported in batches with an intermediate fat level (15% of backfat). The results indicated that fibre could be suitable for use in the manufacture of dry fermented sausages     

鲶鱼发酵香肠的研制

为了获得质量、口感较好的鲶鱼发酵香肠,通过发酵剂适应性试验,选择用戊糖片球菌,植物乳杆菌和木糖葡萄球菌按1:1:1比例混合生产鲶鱼发酵香肠,在接种量、温度、相对湿度单因素试验的基础上结合正交实验,通过感官评价,确定鲶鱼发酵香肠的最佳生产工艺。试验结果表明:鲶鱼发酵香肠的最佳生产工艺为:三种菌的接种量为106cfu/g,发酵温度为25℃,发酵相对湿度为90%。     

预先包装发酵香肠表层的粉霜——肌酸

多次观察到在预先包装的生发酵香肠表层的不理想外衣,有时把粉霜的成分认为是D,L-乳酸盐。现在,我们首次鉴定肉产生的肌酸是在预包装细的生干肠表层结晶粉霜的来源。质谱分析粉霜和质谱分析纯一水肌酸结果基本是一致的,霜层含有83%的肌酸(对应的94%一水肌酸晶体)。香肠中肌酸含量为2.4mg/g,为了检测香肠粉霜中的肌酸,建议使用以VOGES-PROSKSUER反应为基础的检测方法。     

Effect of fat level and ripening temperature on biochemical and sensory characteristics of naturally fermented Turkish sausages (sucuk)

Changes in chemical and sensory characteristics of naturally fermented Turkish sausages during ripening were evaluated for three fat levels (10, 20 and 30%) and two different ripening temperatures, i.e. 20–22 and 24–26 °C. Fat level, ripening temperature and time affected total acidity, free fatty acids (FFA) and thiobarbituric acid (TBA) values. Both higher fat content and higher temperature resulted in higher FFA and TBA values during ripening, indicating high lipolytic and oxidative activity. TBA values showed an increase from the first to the ninth day, but were lower at 20–22 °C than at 24–26 °C. High fat level and temperature adversely affected rancid flavor and overall acceptability.     

Creatine blooms on the surface of prepacked fermented sausages

Undesired coatings have been repeatedly observed on the surface of prepacked raw fermented sausages. In some cases d,l-lactate was identified as a major component of these blooms. We now for the first time identified meat-borne creatine as the source of white crystalline blooms on prepacked thin-calibre dry raw sausages. The mass spectra of the blooms and of authentic creatine monohydrate were essentially identical. The coatings contained 83% creatine corresponding to 94% crystalline creatine monohydrate. The creatine concentration in the sausages was 2.4 mg/g. For the detection of creatine in white sausage blooms a rapid test based on the VOGES-PROSKAUER reaction is suggested.     

Effect of replacing beef fat and tail fat with interesterified plant oil on quality characteristics of Turkish semi-dry fermented sausages

Seven treatments of Turkish semi-dry fermented sausage were manufactured by replacing 0, 20, 60 and 100% of beef fat and tail fat by interesterified palm (IPaO) and cottonseed oils (ICO). pH, fat and moisture content, penetrometer value and fatty acid composition as well as sensory attributes were determined for each formulation. Addition of interesterified plant oils (IPOs) was found to significantly affect the miristic, palmitic, palmitoleic, stearic, oleic, linoleic acid content and also saturated to unsaturated (SFA/UFA), polyunsaturated to saturated (PUFA/SFA) ratios of treatments ( p<0.05), however no significant change in the miristoleic acid content was recorded ( p>0.05). Sensory evaluation indicated that control sausages had the highest sensory scores. However the sausages produced with IPOs were also acceptable. Therefore, further research is needed to improve the sensory attributes of these products, particularly their flavour.     

Effect of selected mould strains on lipolysis in dry fermented sausages

 Several batches of fermented sausages were prepared and inoculated with five strains of moulds belonging to the genera Penicillium and Mucor, selected for their enzymatic activity, and a strain of Penicillium nalgiovense obtained as a commercial starter culture. Control batches were manufactured similary, but without inoculation. Sausages were produced with either artificial or natural casings, and very similar results were obtained with both. The evolution of the different lipidic fractions was monitored, paying special attention to the free fatty acid (FFA) fraction. Two strains presented a high lipolytic activity as indicated by the rise in FFA in comparison to control batches. In conclusion, not all the mould strains contributed to the lipolytic process occurring during sausage ripening and, therefore, not all of these had a positive effect on the final quality of the product. If moulds are to be used for this purpose it is, therefore, necessary to carefully select suitable moulds beforehand. Received: 25 September 1998 / Revised version: 4 February 1999     

Perceptual masking of boar taint in Swedish fermented sausages

Surgical castration of male piglets has traditionally been practiced to avoid development of boar taint in pork meat which can occur if entire male pigs are raised. Boar taint is commonly characterised as exhibiting the odour and flavour of urine and manure. This study involves sensory characterisation of the possibilities to mask boar taint in meat from entire male pigs by fermentation and smoking to maintain high sensory quality in meat products if castration is prohibited. Model and commercial type Swedish fermented sausage products based on low or high levels of boar tainted fat, three different starter cultures and two different levels of smoking were studied. In the model sausages, liquid smoke masked the perception of boar taint. In contrast, the smoking procedure of the commercial sausages was insufficient to totally mask the perception of boar taint. In both the model and commercial sausages, the aroma development from the starter cultures lowered the perception of boar taint but was insufficient for total perceptual masking. Due to the total masking effect of smoking in the model sausages, it was clear that smoke may present a potential solution to remove the perception of boar taint in fermented sausages if the smoking procedure is optimised.