Breastfeeding is a gold standard of feeding of newborns and infants. Tandem breastfeeding (TBF) is feeding two children of different ages at the same time. The knowledge about the composition of human milk in prolonged lactation is still scarce. Milk from tandem breastfeeding women and after weaning was examined. Milk samples were collected from 13 TBF mothers. A 24-h milk collection was done. Analyses of fat, protein, carbohydrate and energy content were performed using MIRIS. Sociodemographic characteristics of TBF mothers was done. Higher fat content, energy value and total protein concentration was found in TBFM milk during tandem breastfeeding, than in milk after weaning the older child. The carbohydrate content remained stable. The composition of breastmilk, in terms of macronutrients, changes after weaning, taking into account the nutritional requirements of the younger child. The milk of nursing mothers in tandem did not show diurnal variability in individual components. These findings suggest an adaptive role of human milk to nutrient requirements of newborn and older children. The results may support the promotion of long breastfeeding, including tandem breastfeeding.

Breast milk is the optimal food for infants and toddlers, providing basic nutrients. It is also a source of many biologically active substances. Among them are hormones responsible for metabolic balance. One of the hormones taken in with breast milk by a breastfed baby is leptin. This hormone is involved in the regulation of appetite, informing the brain about the body’s energy resources. Having the correct mechanisms related to the action of leptin is a factor reducing the risk of obesity. The natural presence of leptin in the composition of breast milk suggests that it has a specific role in shaping the health of a breastfed child. Obesity as a disease of civilization affects more and more people, including children. The development of this disease is multifaceted and determined by many factors, including genetic and environmental factors such as eating habits and low physical activity. Behind obesity, there are complex mechanisms in which many elements of the human body are involved. Understanding the effects of breastfeeding as a natural source of leptin can help prevent childhood obesity and development of this disease in future life.

Rapid diagnostics of microbes in hospitals are crucial for promptly identifying infections, enabling timely and appropriate treatment. The study was conducted to evaluate the effectiveness of the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI TOF MS) technology in the microbial profiling of hospital environments and patient samples. The objective was to determine the microbial landscape in swabs collected from hospitalized patients and their immediate environments, using MALDI to compare the capabilities of two systems: BRUKER and ZYBIO. The analysis resulted in 1012 microbial identifications from patient samples (N = 81), encompassing 96 species, and 1496 identifications from hospital surface samples (N = 108), covering 124 species. Predominantly identified microorganisms in patients' samples included Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus capitis, Steptococcus salivarius, and Micrococcus luteus, whereas environmental samples chiefly yielded S. epidermidis, Staphylococcus hominis, Staphylococcus warneri, and Microcccus luteus. 33 species were found in both types of samples, highlighting a significant microbial interchange within hospital settings. Both MALDI systems showed high consistency in results at both genus and species levels. Nevertheless, mismatches in identification between both MALDI systems were noted, particularly within Brevibacterium, Streptococcus, Bacillus, Staphylococcus, and Neisseria genera. This study presents the precision of MALDI technology in microbial identification and highlights the need for ongoing enhancements, especially in the expansion and updating of databases, to bolster its diagnostic effectiveness further.

Human milk comprehensively meets the nutritional needs of a child, providing not only structural and energy components but also various bioactive factors. Among these, neurotrophic factors and hormones involved in metabolic processes deserve special attention. Studies using enzyme-linked immunosorbent assays compared the content of neurotrophic factors—CNTF, NT-3, and NGF—and hormones, leptin and insulin, in two groups of breast milk samples: early lactation (1–3 months) and extended lactation (>6 months, up to 12 months). The results indicated changes in leptin and insulin levels as the lactation period extended. NGF, leptin, and insulin were present in milk samples from both study groups, with leptin and insulin levels being higher in the early lactation group. CNTF and NT-3 were not detected in any of the samples from either study group. The analyses confirmed that human milk from women who breastfeed for extended periods remains a source of biologically active components and macronutrients that support a child’s development and health.

The specific fermented matrices influence microbial diversity and proteomic adaptations being crucial for optimising fermentation efficiency and effective microbial identification. Therefore, the study aimed to investigate the impact of plant‐based fermentation matrices and their physicochemical composition on microbial diversity and MS‐protein profiles. Microbial communities were characterised using MALDI‐TOF MS and 16S rRNA sequencing. Physicochemical analyses were conducted on the 10 fermentation matrices. The sequencing verified low‐confidence MALDI identifications and assessed species‐level microbial diversity. Combined MALDI‐TOF MS and 16S rRNA gene sequencing confirmed the presence of 24 species across five taxonomic classes and revealed strong matrix‐dependent variation in the lactic acid bacteria composition. A significant positive correlation was observed between Lactiplantibacillus pentosus abundance and pH, with the presence being negatively associated with Ca and Mg levels in the fermented products. Furthermore, the concentration of carbohydrates and Fe was positively correlated with Corynebacterium amycolatum and Micrococcus luteus . MALDI−TOF MS spectra obtained for the key lactic acid bacteria species revealed differences in protein profiles depending on the type of fermented matrices. The study provides new insights into the interactions between microbial communities and fermentation substrates, emphasising the role of physicochemical properties of plant‐based matrices in shaping microbial diversity and proteomic adaptations.