PCR analysis for meat products authenticity - detection of horse meat

Food adulteration regarding species origin of meats is a common problem in the meat products sector. With regard to horse meat, its undeclared use in food products is not only a fraud, but could present a health risk since is often associated with the presence of the veterinary drug phenylbutazone in meat products. Therefore, it is important to use reliable methods for authentication of meat products regarding their species composition, which are applicable to complex food matrices. Polymerase chain reaction (PCR) with species-specific primers remains the most widely used analytical approach to detect species-related food adulteration due to its high sensitivity and specificity. The aim of the present study was to establish the authenticity of 20 different meat products on the Bulgarian market without declared horse meat content by using a species-specific PCR method. The specificity test of the PCR method used showed no amplification of DNA from beef and pork. A detection limit of 0.01% horse DNA in three-component meat mixtures was established for the PCR method. The PCR method enabled detection of undeclared presence of horse meat in 25% of the analyzed meat products, which demonstrates the need for strict control regarding authenticity in the meat food chain

Proteomes of Lactobacillus delbrueckii subsp. bulgaricus LBB.B5 Incubated in Milk at Optimal and Low Temperatures.

We identified the proteins synthesized by Lactobacillus delbrueckii subsp. bulgaricus strain LBB.B5 in laboratory culture medium (MRS) at 37°C and milk at 37 and 4°C. Cell-associated proteins were measured by gel-free, shotgun proteomics using high-performance liquid chromatography coupled with tandem mass spectrophotometry. A total of 635 proteins were recovered from all cultures, among which 72 proteins were milk associated (unique or significantly more abundant in milk). LBB.B5 responded to milk by increasing the production of proteins required for purine biosynthesis, carbohydrate metabolism (LacZ and ManM), energy metabolism (TpiA, PgK, Eno, SdhA, and GapN), amino acid synthesis (MetE, CysK, LBU0412, and AspC) and transport (GlnM and GlnP), and stress response (Trx, MsrA, MecA, and SmpB). The requirement for purines was confirmed by the significantly improved cell yields of L. delbrueckii subsp. bulgaricus when incubated in milk supplemented with adenine and guanine. The L. delbrueckii subsp. bulgaricus-expressed proteome in milk changed upon incubation at 4°C for 5 days and included increased levels of 17 proteins, several of which confer functions in stress tolerance (AddB, UvrC, RecA, and DnaJ). However, even with the activation of stress responses in either milk or MRS, L. delbrueckii subsp. bulgaricus did not survive passage through the murine digestive tract. These findings inform efforts to understand how L. delbrueckii subsp. bulgaricus is adapted to the dairy environment and its implications for its health-benefiting properties in the human digestive tract. IMPORTANCELactobacillus delbrueckii subsp. bulgaricus has a long history of use in yogurt production. Although commonly cocultured with Streptococcus salivarius subsp. thermophilus in milk, fundamental knowledge of the adaptive responses of L. delbrueckii subsp. bulgaricus to the dairy environment and the consequences of those responses on the use of L. delbrueckii subsp. bulgaricus as a probiotic remain to be elucidated. In this study, we identified proteins of L. delbrueckii subsp. bulgaricus LBB.B5 that are synthesized in higher quantities in milk at growth-conducive and non-growth-conductive (refrigeration) temperatures compared to laboratory culture medium and further examined whether those L. delbrueckii subsp. bulgaricus cultures were affected differently in their capacity to survive transit through the murine digestive tract. This work provides novel insight into how a major, food-adapted microbe responds to its primary habitat. Such knowledge can be applied to improve starter culture and yogurt production and to elucidate matrix effects on probiotic performance

Isolation and selection of sauerkraut lactic acid bacteria producing exopolysaccharides

Fermented plant-based foods, including sauerkraut, offer high nutritional and functional value. Their microflora is dominated by lactic acid bacteria which are a source of different substances with health- promoting benefits and diverse applications in the food industry. Production of exopolysaccharides (EPSs) by lactic acid bacteria attracts particular interest in the food industry due to their rheological properties. In the present study, we isolated 20 strains of lactic acid bacteria from traditional Bulgarian sauerkraut. The isolates were identified by 16S rDNA sequencing and were attributed to Lactiplantibacillus plantarum (75%) and Pediococcus pentosaceus (25%). All strains were screened for their ability to synthesize exopolysaccharides, and 6 of them proved positive. Since culture media composition and especially the carbon source is a critical factor influencing the yield of bacterial EPSs, the impact of various carbon sources on the EPSs synthesis by the selected producers was explored. The best results were obtained by using glucose and sucrose as sole carbon sources

Effects of sourdough on rheological properties of dough, quality characteristics and staling time of wholemeal wheat croissants

The present study aimed to obtain good quality croissants from wholegrain wheat flour using baking sourdoughs prepared from single starter cultures of Pediococcus acidilactici 02P108 (PA), Pediococcus pentosaceus SM2D17 (PP) and Enteroccocus durans 09B374 (ED) as an attempt to overcome the usual negative effects of the wholegrain flour on the characteristics of this specific bakery product group. Results showed that the addition of sourdough in the wholegrain wheat dough had similar performance as that of conventional baker’s yeast regarding the rheological characteristics of dough. The dynamic viscosity of all sourdough-leavened samples remained higher than that of the control sample at all tested shear rates. A positive effect of sourdoughs used on the development of baking dough was observed in terms of specific volume improvement, higher degree of softening, and reduced baking loss. However, these positive effects were found as strain-specific. The use of Enteroccocus durans 09B374-made sourdough showed the most distinguished sensory characteristics and the best results regarding croissant staling during storage. The study demonstrated that sourdoughs used in wholemeal wheat croissant dough had positive effect on the quality characteristics and shelf-life of products. However, strain selection proved as of key importance for the successful production of wholemeal wheat croissants.info:eu-repo/semantics/publishedVersio

16S-rRNA-Based metagenomic profiling of the bacterial communities in traditional Bulgarian sourdoughs

Sourdoughs (SDs) are spontaneously formed microbial ecosystems composed of various species of lactic acid bacteria (LAB) and acid-tolerant yeasts in food matrices of cereal flours mixed with water. To date, more than 90 LAB species have been isolated, significantly impacting the organoleptic characteristics, shelf life, and health properties of bakery products. To learn more about the unique bacterial communities involved in creating regional Bulgarian sourdoughs, we examined the metacommunities of five sourdoughs produced by spontaneous fermentation and maintained by backslopping in bakeries from three geographic locations. The 16S rRNA gene amplicon sequencing showed that the former genus Lactobacillus was predominant in the studied sourdoughs (51.0–78.9%). Weissella (0.9–42.8%), Herbaspirillum (1.6–3.8%), Serratia (0.1–11.7%), Pediococcus (0.2–7.5%), Bacteroides (0.1–1.3%), and Sphingomonas (0.1–0.5%) were also found in all 5 samples. Genera Leuconostoc, Enterococcus, Bacillus, and Asaia were sample-specific. It is interesting to note that the genus Weissella was more abundant in wholegrain samples. The greatest diversity at the species level was found in the former genus Lactobacillus, presented in the sourdough samples with 13 species. The UPGMA cluster analysis clearly demonstrated similarity in species’ relative abundance between samples from the same location. In addition, we can conclude that the presence of two main clusters—one including samples from mountainous places (the cities of Smolyan and Bansko) and the other including samples from the city of Ruse (the banks of the Danube River)—may indicate the impact of climate and geographic location (e.g., terrain, elevation, land use, and nearby water bodies and their streams) on the abundance of microbiome taxa. As the bacterial population is crucial for bread standardization, we expect the local bakery sector to be interested in the relationship between process variables and their effect on bacterial dynamics described in this research study.info:eu-repo/semantics/publishedVersio

Towards harmonized approaches for mycotoxin analyses: an assessment

Abstract Mycotoxins (the poisonous metabolites of certain filamentous fungi) are potential contaminants of staple food commodities and, if uncontrolled, may present a significant public health hazard. In many jurisdictions, questions relating to mycotoxin contamination are addressed at both generic and specific levels by food-safety legislation. Key to the successful management of the mycotoxin question, both in terms of verifying food-safety measures by the agri-food businesses and ensuring compliance with statutory limits by enforcement agencies, is the use of reliable sampling and analytical methodology. Evidence from European Union Rapid Alert System for Food and Feed data suggest that harmonization of methodologies used to determine the mycotoxin content of foods would contribute to improved compliance at both regulatory and commercial levels

Grain quality parameters of wintering oat genotypes (Avena Sativa L.)

In the period 2010-2012 in the experimental field of the Department of Crop Production in Agricultural University-Plovdiv (Bulgaria) field experiment was conducted with 8 lines and 2 cultivars (Dunav 1 and Resor 1) wintering oats.The experiment was set in a standard method in three repetitions with the size of the plots 10.5 m2. There was foundsome grain quality parameters in order to assess the potential of wintering genotypes. Line Kt 718 (14.6%) and line07/Z1 (14.51%) have the highest amount of crude protein in the grain. The fat content is 5.04% (Kuceviste) to 8.89%(Kt 718). Starch has values which are similar for different genotypes. Line 07/Z1 has a higher value – 46.93%. Theamount of ß-glucans in the grain of the tested genotypes reached 3.9%

Productivity potential of wintering oat genotypes (Avena sativa L.) under the south Бulgaria agroecological conditions

In the period 2010 – 2013 a field experiment with 8 lines and 2 cultivars (Dunav 1 and Resor 1) wintering oats was conducted in the Agricultural university - Plovdiv, Bulgaria. The investigation was performed by the standard method in 3 replications in 10.5 m2 lots. From the researched genotypes highest of greatest mass of grain at line 07/Z1. Highest potential of grain yield shows 07/Z1 (421.89 kg/da), followed by line M-K – 402.64 kg/da and Kt 651 (394 kg/da). The researched genotypes differ in date of maturity

PCR analysis for meat products authenticity - detection of horse meat

Food adulteration regarding species origin of meats is a common problem in the meat products sector. With regard to horse meat, its undeclared use in food products is not only a fraud, but could present a health risk since is often associated with the presence of the veterinary drug phenylbutazone in meat products. Therefore, it is important to use reliable methods for authentication of meat products regarding their species composition, which are applicable to complex food matrices. Polymerase chain reaction (PCR) with species-specific primers remains the most widely used analytical approach to detect species-related food adulteration due to its high sensitivity and specificity. The aim of the present study was to establish the authenticity of 20 different meat products on the Bulgarian market without declared horse meat content by using a species-specific PCR method. The specificity test of the PCR method used showed no amplification of DNA from beef and pork. A detection limit of 0.01% horse DNA in three-component meat mixtures was established for the PCR method. The PCR method enabled detection of undeclared presence of horse meat in 25% of the analyzed meat products, which demonstrates the need for strict control regarding authenticity in the meat food chain

Isolation and Characterization of Lactic Acid Bacteria and Yeasts from Typical Bulgarian Sourdoughs

Traditional sourdoughs in Bulgaria were almost extinct during the centralized food production system. However, a rapidly developing trend of sourdough revival in the country is setting the demand for increased production and use of commercial starter cultures. The selection of strains for such cultures is based on geographical specificity and beneficial technological properties. In this connection, the aim of this study was to isolate, identify and characterize lactic acid bacteria (LAB) and yeasts from typical Bulgarian sourdoughs for the selection of strains for commercial sourdough starter cultures. Twelve samples of typical Bulgarian sourdoughs were collected from different geographical locations. All samples were analyzed for pH, total titratable acidity and dry matter content. Enumeration of LAB and yeast was also carried out. Molecular identification by 16S rDNA sequence analysis was performed for 167 LAB isolates, and 106 yeast strains were identified by ITS1-5.8S-ITS2 rRNA gene partial sequence analysis. The LAB strains were characterized according to their amylolytic and proteolytic activity and acidification capacity, and 11 strains were selected for further testing of their antimicrobial properties. The strains with the most pronounced antibacterial and antifungal activity are listed as recommended candidates for the development of starter cultures for sourdoughs or other food products