Levels of Se, Zn, Mg and Ca in commercial goat and cow milk fermented products: Relationship with their chemical composition and probiotic starter culture

Occurrence and health risk assessment of mineral composition and aflatoxin M1 in cow milk samples from different areas of Sicily, Italy

This study aimed to determine 16 mineral elements (Cd, Pb, As, Na, Mg, Al, Ca, K, Cr, Mn, Fe, Ni, Cu, Zn and Se) using inductively coupled plasma mass spectrometry (ICP-MS) and a direct mercury analyzer (DMA-80) for Hg evaluation. Aflatoxin M1 was determined by high-performance liquid chromatography with fluorescence detection (HPLC-FLD) in cow milk samples. This research considered 180 milk samples, 20 by province (Palermo, Catania, Messina), collected for a period of three years (2020-2022) to assess the potential risks for consumer, the safety status and nutritional quality related to mineral intake by consuming of milk. All samples showed a Pb concentration below the limit reported by European Regulation 915/2023. Cadmium and Hg concentrations were below the Limit Of Quantification (LOQ) in all samples analyzed. The milk samples analyzed proved to be a good source of Ca (up to 44.5 % of the dietary reference values), with well percentages also for Na (up to 7.6 %), K (up to 23.1 %) and Mg (up to 11.1 %). Regarding trace elements, the results reported that chromium requires attention; its value was always higher than 168.8 % in all samples analyzed. Levels of arsenic and lead were up to 20.2 % and up 7.1 % respectively. Aflatoxin M1 concentrations were below the limit of detection (< 0,009 mcg/kg) in all milk analyzed. Therefore, further studies are needed to safeguard consumer health, the quality of the product and to assess the state of animal health.

Tracking microbial quality, safety and environmental contamination sources in artisanal goat cheesemaking factories

A harmonised microbiological survey was performed in two artisanal factories of raw goat milk cheeses (A and B) located in the Andalusian region (Spain). A total of 165 different control points or samples (raw materials, final products, food-contact surfaces [FCS], and air) were examined as microbial and pathogen sources of contamination of artisanal goat raw milk cheeses. For raw milk samples analysed from both producers, the concentrations of aerobic-mesophilic bacteria (AMB), total coliforms, coagulase-positive Staphylococcus spp. (CPS), lactic-acid bacteria (LAB) and moulds and yeasts ranged between 3.48 and 8.59, 2.45-5.48, 3.42-4.81, 4.99-8.59 and 3.35-6.85 log cfu/mL respectively. For the same microbial groups, the analysis of raw milk cheeses revealed concentrations ranging from 7.82 to 8.88, 2.00-6.82, 2.00-5.28, 8.11-9.57 and 2.00-5.76 log cfu/g, respectively. Although the raw material analysed from producer A presented higher microbial loads and between-batch variability, it was B the producer with the most loaded final products. Regarding the microbial air quality, the fermentation area, storage room, milk reception and packaging room were the most AMB loaded places, while the ripening chamber was the area with higher fungal loads in bioareosol from both producers. Conveyor belts, cutting machine, storage boxes and brine tank were highlighted as the most contaminated FCS evaluated. Staphylococcus aureus was the only pathogen detected within the set of 51 isolates from samples as revealed by MALDI-TOF and molecular PCR, with a prevalence of 12.5% for samples from the producer B. The public health risk attributed to the consumption of artisanal goat cheese should not be neglected, and may consider the whole cheesemaking processing chain, from microbiological quality of raw milk to the ready-to-eat final product, especially concerning the presence of S. aureus.

Microwave-assisted digestion method using diluted nitric acid and hydrogen peroxide for the determination of major and minor elements in milk samples by ICP-OES and ICP-MS

A novel method for microwave-assisted digestion of milk samples using diluted HNO₃and H₂O₂ with a single reaction chamber was developed for elemental analysis by ICP-based techniques. The optimal conditions for digestion were 0.25 g of sample mass, 6 mL of 0.1 molL^-1HNO₃and 2 mL of 30% H₂O₂ at 250 ℃ and 160 bar. The optimized procedure resulted in low residual carbon content and residual acidity of 260 mgL^-1 and 0.06 mol L^-1, respectively. The limits of detection ranged from 0.286ոg g^-1(Ca) to 82.990ոg g^-1(Fe). In addition, the proposed method was considered an excellent green analysis method with a final score of 87 based on the analytical Eco-Scale. Finally, the method was validated and applied to the determination of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sb, Se, and Zn in milk samples from South Korea.

Consumption of Goat Cheese Naturally Rich in Omega-3 and Conjugated Linoleic Acid Improves the Cardiovascular and Inflammatory Biomarkers of Overweight and Obese Subjects: A Randomized Controlled Trial

This study examines the value of a goat cheese naturally enriched in polyunsaturated fatty acids (PUFA) (n-3 PUFA and conjugated linolenic acid (CLA)) as means of improving cardiovascular and inflammatory health. Sixty-eight overweight and obese subjects (BMI ≥ 27 and <40 kg/m²), with at least two risk factors for cardiovascular disease (CVD) in a lipid panel blood tests, participated in a randomized, placebo-controlled, double-blind, parallel designed study. The subjects consumed for 12 weeks: (1) 60 g/d control goat cheese and (2) 60 g/d goat cheese naturally enriched in n-3 PUFA and CLA. Diet and physical activity were assessed. Anthropometric and dual-energy X-ray absorptiometry (DXA) tests were performed. Blood samples were collected at the beginning and at the end of the study period. Changes in health status, lifestyle and dietary habits, and daily compliance were recorded. The consumption of a PUFA-enriched goat cheese significantly increased plasma high-density lipoprotein (HDL)-cholesterol, as well as in apolipoprotein B, and it significantly decreased high-sensitivity C-reactive protein concentrations compared to the control goat cheese (p < 0.05). The significant improvement of the plasma lipid profile and inflammatory status of people with risk for CVD due to the consumption of PUFA-enriched cheese suggests a potential role of this dairy product as an alternative to develop high nutritional value food in a balanced diet comprising regular exercise.

Analysis of 17 elements in cow, goat, buffalo, yak, and camel milk by inductively coupled plasma mass spectrometry (ICP-MS)

We analyzed the concentrations of 17 elements including arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), zinc (Zn), strontium (Sr), tin (Sn), aluminum (Al), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), sodium (Na), and selenium (Se) in cow, goat, buffalo, yak, and camel milk in China using inductively coupled plasma mass spectrometry. The concentrations of the elements varied and depended on the milk type. K, Ca, Na, and Mg were the most abundant elements. Fe and Zn concentrations ranged from 1 to 6 μg g⁻¹, while Cu, Al, and Mn concentrations ranged from 0.1 to 1 μg g⁻¹. Trace elements, especially toxic trace elements, were present at very low concentrations; however, Pb concentrations in cow milk reached the MRLs established by the Codex Alimentarius Commission. Data were analyzed by chemometrics to evaluate the correlations between elements in the milk samples. PCA and factor analysis highlighted the relationship between element distribution and milk type. The LDA model correctly identified most milk types. Element analysis combined with chemometrics can be used to distinguish milk types.

17 elements in cow, goat, buffalo, yak, and camel milk were determined by ICP-MS; element analysis combined with chemometrics can be used to distinguish milk types.

Rapid determination of majority cations in yoghurts using on-line connection of capillary electrophoresis with mini-dialysis

An analyser was constructed on the basis of on-line connection of capillary electrophoresis over a short separation path with continuous mini-dialysis sample collection. The developed instrument was employed for simultaneous determination of the majority minerals K⁺, Ca²⁺, Na⁺ and Mg²⁺ (and possibly NH₄⁺ ions) in commercially available unflavoured yoghurts. The cations are released from the organic structures by digestion with boiling 6 mol/L HCl. They were separated from residues of the organic matrix by a dialysis probe and were transferred to a stream of water. From the continuous stream, the dialysate was injected into the separation capillary through a flow-gating interface. Within the reliability interval, the determined total mineral content was equal to their contents stated on the yoghurt labels and the content determined by flame atomic absorption spectrometry and complexometric titration. The relative standard deviation of the electrophoretic determination is mostly about 5%.

Assessment of safety and quality of fermented milk of camels, cows, and goats sold and consumed in five localities of Burkina Faso

Background and Aim:

Fermented milk is food produced and consumed all over the world and plays an important role in human nutrition. This work aimed to evaluate the microbiological and physicochemical quality and mineral composition of fermented milk consumed in Burkina Faso.

Materials and Methods:

A total of 114 samples of fermented milk from camels, goats, and cows were purchased in the market in five localities in Burkina Faso; Bobo Dioulasso, Djibo, Dori, Gorom-Gorom, and Sebba. Microbiological and physical parameters were monitored using standards methods.

Results:

Microbiological analysis of fermented milks showed high average values of 7.60±1.50×10⁹ colony-forming unit per milliliter (CFU/ml), 5.72±3.60×10⁷ CFU/ml, 5.53±2.00×10⁵ CFU/ml, 1.97±0.18×10³ CFU/ml, 1.98±0.25×10³ CFU/ml, and 0.10±0.09×10³ CFU/ml for total microbial flora, lactic acid bacteria, yeasts and molds, Staphylococcus aureus, total coliforms, and thermotolerant coliforms, respectively. None of the samples were contaminated by Salmonella or Shigella. The average values of pH, acidity, dry matter, ash, fats, proteins, and total carbohydrates content of samples were ranged, respectively: 3.830-4.137, 1.888-2.822%, 8.271-13.004%, 0.199-0.476%, 1.210-3.863%, 2.125-3.764%, and 3.080-5.428 % (w/w). Na/K and Ca/Mg ratio ranged from 0.104 to 0.909 and from 3.392 to 16.996, respectively. Total microbial flora, yeasts and molds, total coliforms, fats, calcium, potassium, iron, and zinc were significantly different.

Conclusion:

This research contributed in the evaluation of the hygienic and nutritional qualities of local fermented milk. Results obtained in this study confirm the need to set up the training program on the sanitary condition to traditional maker’s to ensure the good fermented milk with high organoleptic and nutritional qualities.

Detection of selected trace elements in yogurt components

The objective of this study was to determine the concentrations of Cu, Cd, Pb, Mn, Cr, Co, Ni, Zn, and Hg in the white and fruit parts of commercially available yogurts (n = 30) from Nitra markets (Slovak Republic). The results were correlated to determine their relationships. Three yogurt fruit flavors were chosen and tested, strawberry (n = 10), blueberry (n = 10), and cherry (n = 10). The elements were analyzed using atomic absorption spectrophotometry. Higher concentrations of toxic elements, such as Cd and Pb, were found in the fruit parts of the yogurt, and in some cases, the tolerable limit was exceeded. The white part of the yogurt was not contaminated by toxic elements. White yogurt is a good source of nutrients for humans, but the fruit part in yogurt requires detailed monitoring and improvements in the processing techniques.

Lead Concentrations in Raw Cow and Goat Milk Collected in Rural Areas of Croatia from 2010 to 2014

A total of 249 cow and 33 goat milk samples were collected in rural areas of Croatia during the period 2010-2014. Lead concentrations in milk samples were analyzed by graphite furnace-atomic absorption spectroscopy. Mean Pb concentrations in milk ranged from (μg/kg): cow 10.8-12.2; goat 9.33-60.0. The highest Pb level of 131 μg/kg in cow milk was measured during 2014. There were no significant differences in Pb levels between cow and goat milk and also in goat milk among the analysed years. However, significant differences were found in cow milk among years. The highest Pb was determined in 2011 (157 μg/kg in goat milk). The calculated estimated weekly intakes of Pb concentrations for cow and goat milk contribute only 1.37 % and 1.84 % to the provisional tolerable weekly intake. Therefore, the consumption of milk from both species should not pose a consumer health risk.

Does Lactobacillus plantarum or ultrafiltration process improve Ca, Mg, Zn and P bioavailability from fermented goats' milk?

Ca, Mg, Zn and P bioavailability from two experimental ultrafiltered fermented goats' milks (one of them with the probiotic Lactobacillus plantarum and another one without it), and fermented goats' milk samples available in the market were evaluated. Solubility, dialysability and a model combining simulated gastrointestinal digestion and mineral retention, transport and uptake by Caco-2 cells were used to assess bioavailability. The highest Ca, Mg, Zn and P bioavailability values always corresponded to the fermented milk developed by our research group, which could be explained by the effect of milk ultrafiltration. The fermented milk with L. plantarum showed higher Ca retention than the ones without the microorganism, and major Ca uptake when compared to commercial products. This fact could be attributed to a positive effect exerted by the probiotic strain.

Analysis of minor and trace elements in milk and yogurts by inductively coupled plasma-mass spectrometry (ICP-MS)

This study aimed at analysing the content of 22 minor and trace elements in milk and yogurts from South Korea, using inductively coupled plasma-mass spectrometry (ICP-MS), after digestion using heating block. The analytical method was validated by detection limits, precision, accuracy and recovery experiments, obtaining satisfactory results in all cases. Results of both minor and trace elements were found mostly similar in all varieties of milk and yogurts studied. Copper and manganese were comparatively high in fruit mixed yogurts, while selenium was high in milk samples. The overall concentrations of minor elements were found to have good nutritional values in accordance to RDA. Zn showed the highest concentration, followed by Rb, Se, Sr and Cr. The level of toxic trace elements, including As, Cd and Pb were very low and did not pose any threat to consumers.

The probiotic bacterial strain Lactobacillus fermentum D3 increases in vitro the bioavailability of Ca, P, and Zn in fermented goat milk

We determined calcium, magnesium, phosphorus and zinc levels in a total of 27 samples of commercial goat- and cow-milk fermented products and 9 samples of a goat-milk fermented product with addition of a probiotic bacterial strain, Lactobacillus fermentum D3, manufactured experimentally by our research group. Atomic absorption spectroscopy with flame atomization and UV/VIS spectrophotometry were used as analytic techniques. The results of an in vitro digestion process showed that the bioavailability of calcium, phosphorus, and zinc was significantly higher in our fermented milk containing the probiotic bacterial strain than it was in commercial goat-milk fermented products. Furthermore, our product showed a significantly higher bioavailability of calcium and zinc compared to goat- and cow-milk fermented products made with other microorganisms. We conclude that, in in vitro assays, strain D3 seems to increase the bioavailability of these minerals and that this new product may constitute a better source of bioavailable minerals compared to other products already on the market.