Assessment of the content of macronutrients and microbiological safety of dry dog foods.

In Europe, there are no legal regulations specifying maximum allowable limits for pathogenic bacteria or fungi and yeasts in dog food. For proximate composition, the European Pet Food Industry Federation (FEDIAF) nutritional guidelines provide minimum recommended levels for protein and fat only, not for other ingredients and no safe maximum levels. Therefore, the aim of this study was to evaluate the microbiological safety of 35 dry dog foods, taking into account the division into foods with grains as the main plant ingredient and those described as grain-free. We assumed that grain-included foods are more susceptible to the presence of the total number of aerobic bacteria. This parameter is an essential, hygienic criterion informing about the microbiological safety of the pet food. It also inform about the microbiological quality of the food ingredients used, the effectiveness of decontamination during the production process, sanitary and hygienic conditions during the acquisition, processing and marketing of pet food and its components. In the case of macronutrients, the results in some cases were multiples of the minimum recommended levels. The most important microorganisms that presence was found in the analyzed dog foods were indicator bacteria (E. coli and coliform bacteria, Clostridium perfringens), whose presence in feed constitutes microbiological contamination. They inform about sanitary and hygienic conditions during the production and storage of the pet food. The current guidelines recommend microbiological testing of food for the presence of Salmonella bacilli as the basic indicator for assessing the sanitary quality. No Salmonella spp. was detected in any of the foods. The remaining analyzed bacteria (Proteus spp., Enterococcus spp., Staphylococcus spp.) as well as molds and yeasts, were present in both grain-included and grain-free foods. The obtained results showed that in terms of microbiological safety, grain-included foods come out worse, because microorganisms were detected more frequently in this type of dry dog food.

Mineral and heavy metal content in dry dog foods with different main animal components.

Dog caregivers, mainly for economic reasons and easy availability, choose dry, over the counter diets (OTC). The mineral composition of OTC foods depends primarily on the components used in the production of the pet food. Regardless of the main component of the food, it must meet the recommended minimum mineral content, established by nutritional guidelines. Therefore, the aim of this study was to determine the mineral (Ca, K, Mg, Na, Fe, Mn, Zn, Cu, Mo) and heavy metal content (Pb, Co, Cd, Cr, Ni) using the methods of colorimetry and mass spectrometry, of OTC dry dog foods and to compare with the FEDIAF and AAFCO nutritional guidelines. Dry foods pose no risk to dogs in terms of heavy metal content. The worst results in terms of mineral content were obtained in mixed foods, therefore it is worth considering feeding the dog a mono-protein food. The PCA analysis disproved our hypothesis and revealed that the main animal source did not statistically significantly affect the levels of minerals and their ratios. However, the analysis of contrasts confirms the differentiation of the content of individual minerals between the groups of foods. For the first time, we proved that pet food with a mineral composition similar to the MIN-RL may be characterized by unfavorable mineral ratios.

Recovery of microelements from municipal sewage sludge by reed canary grass and giant miscanthus.

The aim of the study was to evaluate the content, uptake, and utilization of Al, Mn, Fe, Co, and Mo from municipal sewage sludge by the reed canary grass (RCG) and the giant miscanthus (MG). The impact of sewage sludge on the mass ratios between microelements contained in the plant biomass was analyzed as well. The long-term field experiment consisted in application of four levels of fertilization with sewage sludge: 10, 20, 40, and 60 Mg DM·ha-1. A non-fertilized control object (0 Mg DM·ha-1) was used as well. The miscanthus biomass was characterized by higher content of Al and Mn, whereas higher levels of Fe, Co, and Mo were determined in the reed canary grass biomass. As in the case of the element content, the giant miscanthus was characterized by highest level of Al and Mn uptake, while the highest uptake of Fe, Co, and Mo was exhibited by the reed canary grass. In the group of the analyzed microelements, the giant miscanthus showed the highest the recovery of Mo (47%) followed by Mn (39%), Fe (35%), and Co (15%), and the lowest uptake was determined in the case of Al (5%).

In addition to the use of their biomass for the production of renewable energy, energy crops (reed canary grass, giant miscanthus) can be used to recover microelements from municipal sewage sludge. Energy crop biomass can therefore be a potential source of microelements in animal feed. Attention was paid to the mass ratios of Fe:Mn, Fe:Al, Fe:Co, Fe:Mo, Mn:Al, Mn:Co, Mn:Mo, and Co:Mo in the biomass yield of the species used.

Chemical properties of the coffee grounds and poultry eggshells mixture in terms of soil improver.

Spent coffee grounds (SCG) as well as chicken (CES) or duck eggshells (DES) left over from the artificial hatching technology are proposed as potential soil improver and/or organic-mineral fertiliser components. Therefore, it seems interesting and necessary to evaluate the chemical composition of these wastes and their mixtures in terms of their possible use for that purpose. The study was conducted under the incubation experiment conditions using a mixture of SCG and eggshells (10:1 ratio). Macronutrients, i.e. C, N, S, were determined by the catalytic combustion method, while P, K, Mg, Ca, Na by atomic spectrometry. It was found that SCG were rich in C, N, P, and K, while eggshells in Ca, Mg, Na, and S. However, CES compared to DES were richer in deacidifying components (i.e. Ca, Mg, K). At the same time, the content of macronutrients in eggshells decreased gradually along with the embryo development. For this reason, the mixture of SCG and shells of unembryonated chicken eggs (CES I) had the best chemical and usable proprieties. To conclude, the chemical properties of the mixtures of spent coffee grounds and eggshells indicate their possible application in soil bioengineering.

Evaluation of nutritional value and microbiological safety in commercial dog food.

In addition to properly balancing nutritional value in accordance with the needs of a dog, estimating the microbiological quality of dog food is crucial in providing healthy and safe foods. The aim of this study was to examine the quality of dry food for adult dogs, with particular reference to: (1) evaluating the nutritional value and compliance with nutritional guidelines for dogs, (2) comparing the nutritional value of dog foods, with particular emphasis on the division into cereal and cereal-free foods, and (3) evaluating their microbiological safety. All thirty-six evaluated dry dog foods met the minimum European Pet Food Industry FEDIAF requirement for total protein and fat content. The total aerobic microbial count in the analyzed dry dog foods ranged from 2.7 × 102 to above 3.0 × 107 cfu/g. In five (14%) dog foods the presence of staphylococci was detected; however, coagulase positive Staphylococcus (CPS) was not found. Mold presence was reported in one cereal-free dog food and in six cereal foods. In none of the analyzed foods Enterobacteriaceae were found, including coliforms, Escherichia coli and Salmonella spp. Bacteria of the genus Listeria and Clostridium as well as yeasts were also not detected. In conclusion, the evaluated dry dog foods had varied microbiological quality. The detected number of microorganisms may have some implications for long-term consumption of contaminated food. The lack of European Commission standards regarding the permissible amounts of microorganisms in pet food may result in insufficient quality control of these products.

Mineral Composition of Cereal and Cereal-Free Dry Dog Foods versus Nutritional Guidelines.

The aims of the present work are to estimate the nutritional value and to evaluate and compare the levels of macroelements (Ca, P, K, Na, Mg), microelements (Fe, Zn, Mn, Cu), heavy metals (Co, Cd, Pb, Mo, Cr, Ni), and their ratios in extruded complete foods for adult dogs, their compatibility with nutritional guidelines, as well as food profile similarity. Basic composition was determined according to Association of Official Analytical Chemists (AOAC). Analyses for elements were performed using an atomic absorption spectrometer. All the evaluated dry dog foods met the minimum recommended levels for protein and fat. Eighteen tested dog foods (60%) did not meet at least one recommendation of nutritional guidelines. Four dog foods exceeded the legal limit of Fe and five foods exceeded the legal limit of Zn; in one of them, Zn level was almost twice higher. Dog foods with insect protein exceeded the legal limit for Mn content. Eight dog foods had an inappropriate Ca:P ratio. Heavy metals were below detection limit in all analyzed dog foods. The results seem to show the need for regular feed analyses of the elemental composition in raw materials before introducing supplementation and for the monitoring of the mineral composition of finished pet food.

Microorganisms and Biostimulants Impact on the Antioxidant Activity of Buckwheat (Fagopyrum esculentum Moench) Sprouts.

The study analyzes the influence of plant growth promoters and biological control agents on the chemical composition and antioxidant activity (AA) in the sprouts of buckwheat. The AA of cv. Kora sprouts was higher than cv. Panda, with 110.0 µM Fe2+/g (FRAP-Ferric Reducing Antioxidant Power), 52.94 µM TRX (Trolox)/g (DPPH-1,1-diphenyl-2-picrylhydrazyl), 182.7 µM AAE (Ascorbic Acid Equivalent)/g (Photochemiluminescence-PCL-ACW-Water-Soluble Antioxidant Capacity) and 1.250 µM TRX/g (PCL-ACL-Lipid-Soluble Antioxidant Capacity). The highest AA was found in the sprouts grown from seeds soaked in Ecklonia maxima extract and Pythium oligandrum (121.31 µM Fe2+/g (FRAP), 56.33 µM TRX/g (DPPH), 195.6 µM AAE/g (PCL-ACW) and 1.568 µM TRX/g (PCL-ACL). These values show that the antioxidant potential of buckwheat sprouts is essentially due to the predominant hydrophilic fraction of antioxidants. The AA of the sprouts was strongly correlated with total polyphenol content.

Proximate Composition, Minerals and Antioxidant Activity of Artichoke Leaf Extracts.

In this study, leaf extracts from the Green Globe cultivar of artichoke (Cynara scolymus L.), a herbaceous plant of the Asteraceae family, were analyzed to determine the levels of basic nutrients, selected macroelements (K, P, Ca, Mg, and Na) and microelements (Zn, Fe, Mn, Cr, Pb, Cd, and Ni), and their ratios. The antioxidant activity (aa) of the extract was evaluated using ABTS˙+ and DPPH˙+ radicals and the ferric reducing antioxidant power assay (III) (FRAP). Total polyphenolic content was also determined. Macroelement concentrations in the artichoke leaf extract can be presented in descending order as follows: K > P > Ca > Mg > Na. Microelement content in the extract was as follows: Zn > Fe > Cr > Mn. We determined the ratios of elements in artichoke leaf extracts and compared them against the recommended dietary allowance, adequate intake, or tolerable upper intake level. Mean total phenolic content in artichoke leaf extracts was high - 2795 mg CAE/100 g dry matter (DM). The ABTS˙+ assay showed a very high ability of artichoke extract to scavenge free radicals (79.74%), and the antioxidant capacity measured at 1060.8 Trolox/1 g DM. The results show that artichoke extract is a valuable source of minerals and antioxidants that could have applications in the prevention of chronic non-communicable diseases caused by oxidative damage.