Chemical and microbiological characteristics of traditional homemade fresh goat cheeses from Northern Morocco

Analysis of the bacterial diversity in Moroccan Jben cheese using TTGE, DGGE, and 16S rRNA sequencing

This research investigated the physicochemical, microbiological, and bacterial diversity of Jben cheese, a popular artisanal variety in Morocco. The bacterial diversity was explored using culture-independent methods, including temporal temperature gel electrophoresis (TTGE), denaturing gradient gel electrophoresis (DGGE), and high-throughput sequencing (HTS). Significant intra-sample differences were observed for most physicochemical parameters within each milk type, while inter-sample differences occurred between cow and goat cheeses for dry matter and ash. Jben cheese exhibited distinct characteristics, with low pH values of 3.96, 4.16, and 4.18 for cow, goat, and mixed cheeses, respectively. Goat cheeses had higher fat (49.23 g/100 g), ash (1.91 g/100 g), and dry matter (36.39 g/100 g) than cow cheeses. All cheeses displayed high microbial counts, with a notable prevalence of the lactic acid bacteria (LAB) group, averaging 8.80 ± 0.92 log CFU/g. Jben cheese also displayed high contamination levels with total coliforms, faecal coliforms, yeast, and molds. Fatty acid profiling revealed fraudulent practices in Jben cheese marketing, with cow or mixed cheeses sold as goat cheese, as proven by low capric acid concentration. HTS analysis of Jben cheese identified ten genera and twenty-four species, highlighting Lactococcus lactis as predominant. TTGE and DGGE confirmed the presence of L. lactis but failed to provide the detailed profile achieved through HTS analysis. HTS has been demonstrated to be more reliable, whereas TTGE/DGGE methods, though informative, were more time-consuming and less reliable. Despite limitations, the combined use of TTGE, DGGE, and HTS provided a comprehensive view of indigenous bacterial communities in Jben cheese, identifying L. lactis as the main species.

Physicochemical composition, nitrogen fraction and volatile profiles of goat cheese made with artisanal liquid coagulant

In this study, physicochemical composition, nitrogen fractions and volatile compounds of goat cheeses manufactured using artisanal liquid coagulant by four different manufacturers in a mountainous area were investigated. Fresh goat cheeses were characterized by their high fat and high levels of total free amino acids. Volatile profiles were isolated by a solid-phase microextraction technique (SPME/GC-MS) and analyzed by gas chromography-mass spectrometry (GC-MS). In the cheeses, 50 aroma components were identified as ten acids, nine terpens, nine alcohols, eight esters, six aldehydes, five ketones, two volatile phenols and one norisoprenoid with 13 carbon atoms. The major aroma compounds found were nonanoic acid, 2-hexanol and acetoin.

Effects of Lactobacillus fermentum HY01 on the quality characteristics and storage stability of yak yogurt

Lactobacillus fermentum HY01 is a probiotic strain screened from traditional yak yogurt, which can effectively relieve enteritis and constipation. This study aimed to evaluate the effects of HY01 as an adjunct starter on the quality and storage of yak yogurt. A total of 36 main volatile flavor substances were detected in all samples. In particular, more aldehydes, esters, and alcohols were detected in yak yogurt prepared by mixed fermentation of L. fermentum HY01 and starter MY105 (including Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus). The rheological results showed that the yak yogurt prepared by mixed fermentation of L. fermentum HY01 and starter MY105 had higher apparent viscosity and lower tan δ value compared with compared with traditional yak yogurt, yak yogurt with only L. fermentum HY01, and cow yogurt with L. fermentum HY01 and starter MY105. Meanwhile, the conjugated linoleic acid in the yak yogurt prepared by mixed fermentation of L. fermentum HY01 and starter was significantly higher than those in the HY01 group or the yogurt starter group alone. After 28 d of storage at 4°C, the number of HY01 in the yak yogurt prepared by mixed fermentation of L. fermentum HY01 and starter was still higher than 10⁷ cfu/mL, its acidity was lower than 110°T, and its syneresis was the lowest. The results indicated that L. fermentum HY01 could improve the flavor, texture, and storage properties of yak yogurt.

Recent advances in dairy goat products

Goat population world-wide is increasing, and the dairy goat sector is developing accordingly. Although the new technology applied to the goat industry is being introduced slowly because the weight of traditional subsector in the dairy sector, considerable advances have been made in the last decade. Present review focuses on the emerging topics in the dairy goat sector. Research and development of traditional and new dairy goat products are reviewed, including the new research in the use of goat milk in infant formula. The research in alternatives to brine, production of skimmed goat cheeses and the use of different modified atmosphere packaging are also addressed. Special attention is given to antibiotic residues and their determination in goat milk. Functional foods for human benefits are a trending topic. Health properties recently discovered in dairy goat products are included in the paper, with special attention to the antioxidant activity. The dual-purpose use of goats by humankind is affecting the way of how new technology is being incorporated in the dairy goat sector and will certainly affect the future development of dairy goat products.

Technological characterization and sensory evaluation of a traditional Algerian fresh cheese clotted with Cynara cardunculus L. flowers and lactic acid bacteria

Jben is an Algerian traditional fresh cheese produced on a small scale in a limited area of east and west Algeria, in Maghnia and Nadrouma. It is manufactured from raw sheep, cow or goat milks, coagulated with dried flowers of wild thistle Cynara cardunculus L. without starter culture addition. In this work, Jben was made using cow and goat pasteurized milks to improve the microbiological quality. Milk was clotted with crude enzymatic extract of dried flowers of wild thistle C. cardunculus L. In order to obtain a better organoleptic characteristic, the assays of cheese making were realized with adding strains of lactic acid bacteria isolated from traditional cheeses. Physico-chemical and microbiological analyzes were carried out on the manufactured cheeses. Milk was clotted with 0.5% v/v by aqueous extract (40 g/L) of dried flowers of C. cardunculus L. Better organoleptic quality and higher cheese yield were obtained with goat milk. Cheese made from pasteurized goat's milk added with Lactococcus lactis subsp. lactis, and that added with the mixture of lactic acid bacteria strains L. lactis subsp. lactis, Lactococcus raffinolactis, Leuconostoc mesenteroïdes ssp. mesenteroïdes, were the most appreciated. It is believed that the activity of L. raffinolactis in dairy products may contribute to their final sensory characteristics.

Hygiene Quality and Consumer Safety of Traditional Short- and Long-Ripened Cheeses from Poland

The aim of this study was the assessment of the microbiological quality of three types of traditional cheeses which are produced from raw and pasteurized cow’s milk. Two types of cheeses were of the short-ripened type, and one cheese was long-ripened. A microbial examination was conducted for the presence of Salmonella spp. and Listeria monocytogenes microorganisms and the count of aerobic, psychrotrophic, lactic acid bacteria, and coliform bacteria, as well as Escherichia coli, Enterobacteriaceae, Enterococcus spp., Staphylococcus spp., and yeasts. The examined cheeses did not fulfill the microbial criteria for food safety (presence of L. monocytogenes) and process hygiene (exceeded allowable levels of E. coli and coagulase-positive Staphylococcus). The levels of coliform bacteria, E. coli, and Enterobacteriaceae and the presence of Enterococcus faecalis determined in the three examined cheese types indicated that insufficient hygiene procedures were used during the production process. The results of the study indicate that the examined cheeses did not fulfill the microbial criteria for food safety and process hygiene according to the legislation. It is necessary to introduce correction procedures as indicated in the current report.

Effect of different thistle flower ecotypes as milk-clotting in Serra da Estrela cheese

Purpose

Thistle flower (Cynara cardunculus) aqueous extracts, as rich source of milk-clotting peptidases, have been widely used for cheeses marketed under the Registry of the Protected Designation of Origin, as it is the case of Serra da Estrela cheese, manufactured from raw ewes’ milk and without addition of any commercial starter culture. This paper aims at studying the influence of six different ecotypes of thistle flowers in cheese properties during the ripening and of final products.

Design/methodology/approach

Cheeses were produced with different thistle flower extracts and then the clotting time, weight and colour of cheeses, as well as texture properties and sensorial characteristics, were evaluated.

Findings

The clotting time varied from 47 to 66 min, and the weight loss along ripening varied between 32 and 40 per cent. There was some influence of thistle flower ecotype on the colour during ripening and in the final product. The results of texture analysis revealed significant differences between the thistle ecotypes: crust firmness varying from 2.4 to 5.6 N; inner firmness from 0.82 to 1.82 N; stickiness from −0.5 to −1.60 N; adhesiveness from −3.0 to −11.3 N.s; and Ecotype C was particularly distinguishable. Sensorial evaluation revealed differences among the cheeses, with Ecotype C receiving the highest score for global appreciation.

Originality/value

The usage of different extracts of thistle flower to produce Serra da Estrela cheese with different properties is a novelty, and it allows the possibility of manipulating this parameter in the future so as to produce cheeses with specific characteristics, addressed to different consumer targets.