Technological and Sensory Quality and Microbiological Safety of RIR Chicken Breast Meat Marinated with Fermented Milk Products

The aim of the study was to determine the effect of marinating with fermented milk products (buttermilk and sour milk) on the physical characteristics, microbiological quality, and sensory acceptability of Rhode Island Red (RIR) hen meat after the first year of laying use. The hen breast meat was marinated with fermented dairy products, buttermilk and sour milk, by the immersion method for 12 h at 4 °C. The assessed features included the quality of raw and roasted marinated and non-marinated meat in terms of physical characteristics (marinade absorption, water absorption, pH, L*, a*, b* colour, shear strength, texture profile analysis (TPA) test), microbiological parameters, and sensory characteristics. Bacteria were identified by the mass spectrometry method (MALDI-TOF MS Biotyper). Marinating meat with fermented dairy products lightened the colour, decreased the value of shear force, reduced hardness and chewiness, and limited the growth of aerobic bacteria and Pseudomonas spp. Additionally, after heat treatment, the number of identified aerobic bacteria families in the marinated in buttermilk and marinated in sour milk groups was smaller than in the non-marinated muscle group. The sensory evaluation showed a beneficial effect of marinating with buttermilk and sour milk on the tenderness, juiciness, and colour of roasted meat.

Kefir and ayran – traditional fermented products of Russia

The objective of this study was to determine antibacterial activity two traditional fermented milk products from Russia: kefir and ayran. Freshly prepared kefir and ayran was diluted 1/10 with nutrient broth and inoculated with pathogens (log10 5.5-6.5 initial) Escherichia coli EPEC 8621, VTEC 12900VT, Staphylococcus aureus 8632, Clostridia difficile 13832 and Salmonella Typhimurium LT2 and incubated for 24 h at 370C. Growth of all pathogens was suppressed by kefir and ayran with decrease in viable count below the initial value being seen in the cases of kefir and ayran vs Staphylococcus aureus and kefir vs Salmonella typhimurium. In addition, the influence of novel, potential prebiotics, lactitol and chitozan succinate, added to fermented products on antibacterial effect was studied. We concluded that both additives had no additional effect on the antibacterial activity of the fermented products.

Study of rheological characteristics of fermented milk paste with spices

Research object: rheological characteristics of fermented milk pastes with spices. Investigated problem: according to the results of the degree of syneresis and rheological properties, the consistency of the product is characterized. This allows to improve and optimize the technological process for the production of fermented milk products. Main scientific results: the results of the dispersion analysis of spices show that their particle size is in the range of 250 … 400 microns. This size is optimal for the extraction of biologically active substances of spices, which will contribute to greater assimilation by the human body. And also optimally to avoid caking of raw materials and the manifestation of moisture-absorbing properties. It was found that the degree of syneresis of fermented milk pastes with spices is within 10 %. With the addition of cinnamon and fenugreek spices, the degree of syneresis is lower compared to other examples. This is due to the fact that spices contain a solution of fiber, which allows them to retain free moisture. The spice cinnamon is a dried bark that naturally contains polysaccharides, while fenugreek contains up to 30 % mucus, which also has a high moisture-absorbing capacity. With such a low serum separation, the stabilizing effect is sufficient to prevent spontaneous whey separation. Based on the results of the rheological properties of the product, it was established that fermented milk pastes belong to viscoplastic systems with a normal consistency. There was a slight difference in the shear stress index for pastes based on fermented milk low-fat soft dietary cheese and sour cream with a fat mass fraction of 20 % – by an average of 50 Pa. This characteristic is due to the hydrophilic characteristics of the protein. The area of practical use of the research results: scientific research concerns the technology of dairy products in the food industry. Innovative technological product: the obtained scientific result is an opportunity to improve the technological process of fermented milk products. The scope of implementation of an innovative technological product: the results obtained give grounds to assert the ability to translate into a real industrial creation.

Coxiella burnetii DNA in milk, milk products, and fermented dairy products

Introduction Q fever in dairy cattle has been investigated in Latvia since 2012. In 2015, 10.7% of farms tested positive for the DNA of C. burnetii, its aetiological agent, in bulk tank milk. The presence of C. burnetii DNA and infectious bacteria in dairy products has been assessed in several countries, and because Latvian milk may contain them, parallel assessment in this country is recommended. Accordingly, the present study tested shop and farm retail dairy products from Latvia and included foreign products for comparison. Material and Methods Investigation was carried out of 187 samples of a diverse range of dairy products from 41 Latvian milk producers. Twenty-six comparable samples pooled from Estonia, France, Germany, Greece, Italy, Lithuania, the Netherlands, Poland and Spain were also included. The all-countries total number of fermented milk products was 160. Special attention was paid to products that could be more attractive to children because of their added chocolate, cacao, berry and fruit content. DNA was extracted and amplification of C. burnetii IS1111 was performed using a commercial PCR kit. Results Overall positivity was 60.56%. Domestic products were positive more often (60.96%) than foreign ones (57.69%). Only 26.67% of unpasteurised Latvian cow’s milk samples were positive whereas 76.47% of pasteurised equivalents and 63.13% of fermented milk products were. Sweetened and fruit-containing samples were 71.43% positive. Conclusion The shedding of C. burnetii via milk should be monitored and only milk from healthy animals allowed for sale for direct human consumption without pasteurisation. Raw milk quality and the effectiveness of industrial heat treatment and pasteurisation methods in Latvia and other countries should be carefully assessed to ensure adequate consumer health protection.

Evaluation of Technological Attributes of Lactococcus lactis Cultures for Preparation of Dahi and Misti Dahi (Sweetened Dahi)

Background: Dahi and Misti dahi are traditional Indian fermented milk products. The present study was aimed to evaluate the technological attributes of selected six Lactococcus lactis cultures namely NCDC 193, 125, 128, 94, 97 and 314 for preparation of Dahi and Misti dahi. Methods: Six Lactococcus lactis were collected and tested for acidification profile as well as growth rate was also determined in milk with (15%) and without sucrose. Their flavor producing ability, proteolytic ability by OPA method and antimicrobial activity against four spoilage causing microorganisms (Escherichia coli NCDC 134, Staphylococcus aureus NCDC 109, Micrococcus luteus NCDC 131 and Pseudomonas fluorescenes NCDC 316) were evaluated. Result: All the six cultures were able to grow and produce acidity in milk containing 15% sucrose and similar acidification profile as well as growth rate (K) were found in milk without sucrose. Cultures NCDC 193, 128 and 125 were found to produce flavoring compound (diacetyl). Proteolytic activity of the selected cultures ranged between 0.17 to 0.41 mg/mL of Leucine. Among six cultures three Lactococcus lactis cultures NCDC 314, 94 and 97 have shown zone of inhibition against all four test organisms.