Pet Food Samples Research Articles

Validation of a Modified Version of Actero™ Salmonella Enrichment Media for Rapid Detection of Salmonella spp. in Environmental and Food Samples.

Actero™ Salmonella Enrichment Media1 (Actero™ Salmonella) is a culture broth developed to recover Salmonella spp. from foods and environmental surfaces. Performance of Actero™ Salmonella broth has already been assessed and validated (AOAC Performance Tested MethodSM 041403) for the detection of Salmonella spp. in various foods, feeds and environmental samples. This study aimed to validate the performance of a modified version of Actero™ Salmonella broth by incorporating one of the two liquid supplements into the powdered formula. Inclusivity, exclusivity, stability, and lot-to-lot studies were carried out. Raw ground beef, chicken carcass rinse, dry pet food and stainless steel samples were enriched for 14-20 h at 35-39°C and analyzed using real-time PCR assay as well as by direct plating. The Probability of Detection assay confirmed the equivalent performance of the alternative methods as compared to the reference methods. All Salmonella strains, except Salmonella II : 57: z29:-, were able to grow in Actero™ Salmonella broth. One-half of the non-target strains did not grow in Actero™ Salmonella broth, whereas the atypical for Salmonella growth was observed for other non-target microorganisms subsequently plated onto selective and differential agars. Lot-to-lot consistency was demonstrated for three consecutively manufactured lots of the broth. The liquid broth was proven to be stable at 4°C for up to 9 weeks of storage. The incorporation of one of the two specific supplements into a powdered formula of Actero™ Salmonella broth made it more convenient to use without compromising the performance and accuracy.

High variability within pet foods prevents the identification of native species in pet cats' diets using isotopic evaluation.

Domestic cats preying on wildlife is a frequent conservation concern but typical approaches for assessing impacts rely on owner reports of prey returned home, which can be biased by inaccurate reporting or by cats consuming prey instead of bringing it home. Isotopes offer an alternative way to quantify broad differences in animal diets. By obtaining samples of pet food from cat owners we predicted that we would have high power to identify cats feeding on wild birds or mammals, given that pet food is thought to have higher C isotope values, due to the pervasive use of corn and/or corn by-products as food ingredients, than native prey. We worked with citizen scientists to quantify the isotopes of 202 cat hair samples and 239 pet food samples from the US and UK. We also characterized the isotopes of 11 likely native prey species from the southeastern US and used mixing models to assess the diet of 47 cats from the same region. Variation in C and N isotope values for cat food was very high, even within the same brand/flavor, suggesting that pet food manufacturers use a wide range of ingredients, and that these may change over time. Cat food and cat hair from the UK had lower C values than the US, presumably reflecting differences in the amount of corn used in the food chains of the two countries. This high variation in pet food reduced our ability to classify cats as hunters of native prey, such that only 43% of the animals could be confidently assigned. If feral or free ranging cats were considered, this uncertainty would be even higher as pet food types would be unknown. Our results question the general assumption that anthropogenic foods always have high C isotope values, because of the high variability we documented within one product type (cat food) and between countries (US vs. UK), and emphasize the need to test a variety of standards before making conclusions from isotope ecology studies.

Pet Food Quality Assurance and Safety and Quality Assurance Survey within the Costa Rican Pet Food Industry.

Simple SummaryThe health status of pets may be affected by infectious agents transmitted through the feed. The close coexistence between humans and animals makes the safety assurance of pet food paramount. Different unit operations are applied at the industry level to prevent and reduce the presence of physical, chemical, and biological hazards in pet food; through these operations and adequate implementation of good manufacturing practices, the safety of the finished product can be preserved. Costa Rican animal feed production is continually growing, with approximately 1,238,243 metric tons produced in 2018. Production-wise, pet cat and dog food are in fifth place (about 41,635 metric tons per year) amongst animal feeds, and it supplies up to 90% of the national market. Pet food production has increased as a response to the increase in the population of dogs and cats in Costa Rica, where 50.5% of households own at least one dog and indicates more responsible ownership in terms of feeding pets. Part of the process of making dry pet food involves a thermal process called extrusion, which is capable of eliminating the microbial load. However, extrusion can compromise nutritional quality to some extent by denaturing proteins, oxidizing lipids, and reducing digestibility. The objective of this study was to evaluate the quality and safety of dry pet food and to assess the effect of the extrusion process on digestibility and the quality of proteins, amino acids, and fatty acids. Pet food samples were collected before and after extrusion and were used to evaluate Good Manufacturing Practices (GMP), based on Central American Technical Regulation (RTCA 65.05.63:11). In general terms, weaknesses in infrastructure, documentary evidence, and post-process practices were observed in two Costa Rican feed manufactories. Feed safety was surveyed through the analysis of Salmonella spp., Escherichia coli, Listeria spp., Staphylococcus aureus, aerobic mesophilic microorganisms, fungi, and yeasts counts. The extrusion process effectively reduced pathogenic microorganisms, and showed no effect on the digestibility of dog food (p = 0.347), however, it could reduce the availability of some nutrients (e.g., amino acids, fatty acids). Furthermore, a retrospective diagnosis was made for puppy food (n = 68), dog food (n = 158), and cat food (n = 25), to evaluate the history of nutritional quality and safety. Finally, it can be confirmed that the correct implementation of GMP allows feed manufacturers to deliver a product of optimum texture, smell, nutritional composition, and safety.

Evaluation of a Bead-Based Salmonella Molecular Serotyping Method for Salmonella Isolated from Food and Environmental Samples

Salmonella is a leading cause of foodborne illness worldwide, and foods containing Salmonella (except raw meat and poultry products) are considered adulterated. Serotyping of Salmonella is an essential part of surveillance and investigation of outbreaks. This study evaluated a bead-based Salmonella molecular serotyping (SMS) method, which included the O-group 1, H-antigen, alternate target, and O-group 2 assays, compared with traditional serotyping. Salmonella was isolated from food, pet food, and environmental samples or were reference strains. A total of 572 isolates were analyzed by using two formats of the SMS method in comparison with traditional methods: 485 were analyzed by using Radix SMS (a custom user-mixed format), 218 were analyzed by using Luminex SMS (a commercial kit format), and 131 of the total isolates were analyzed by both formats for comparison. The SMS method was evaluated on the basis of the successful identification of antigens by the probes included in the method. The method identified 550 (96.2%) isolates as expected, 6 (1.0%) isolates were not identified as initially expected but were shown to be correctly identified by SMS after reanalysis by traditional serotyping, and 16 (2.8%) isolates not identified as expected possessed an antigen that should have been detected by the method but was not. Among the isolates considered correctly identified, 255 (44.6%) were identified to a single serovar, 44 (7.7%) required additional biochemical testing to differentiate variants or subspecies, and 251 (43.9%) were partially serotyped because probes for some antigens were not in the assay or had allelic variation for known serovars. Whole genome sequencing, SeqSero, and the Salmonella In Silico Typing Resource gave added confirmation for three isolates. Addition of the O-group 2 assay enabled the identification of 55 (9.6%) of 572 isolates. The SMS method could fully or partially serotype most isolates within a day. The SMS method should be a valuable tool when faster screening methods are needed, such as outbreaks and screening large numbers of environmental isolates.

Polyethylene Terephthalate and Polycarbonate Microplastics in Pet Food and Feces from the United States.

Human exposure to microplastics has been a topic of interest, but measurements of exposure are limited. Pet animals are sentinels of human exposure, as they share a common living environment with humans. In this study, 58 pet (cat and dog) foods and 78 pet feces samples were collected from Albany, NY, USA, for the analysis of polyethylene terephthalate (PET) and polycarbonate (PC) by alkali-assisted thermal depolymerization and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) methods. PET was detected at concentrations in the range of <1,500 ng/g to 12,000 ng/g (median: <1,500 ng/g) and <1,500 to 4,600 ng/g (median: <1,500 ng/g) in cat and dog foods, respectively. The concentrations of PET in cat (<2,300-340,000 ng/g, median: 61,000 ng/g) and dog (7700-190,000 ng/g, median: 30,000 ng/g) feces were 1-2 orders of magnitude higher than those in pet food samples. A significant positive correlation was found between the concentrations of the monomers (i.e., TPA and BPA) and the corresponding MPs in cat feces. The calculated mean estimated daily intake of PET and PC (calculated from pet food) was lower than that of the mean cumulative daily intake (calculated from pet feces), which suggested that diet is a minor source of exposure to PET and PC in pets.

Target Analysis and Retrospective Screening of Multiple Mycotoxins in Pet Food Using UHPLC-Q-Orbitrap HRMS.

A comprehensive strategy combining a quantitative method for 28 mycotoxins and a post-target screening for other 245 fungal and bacterial metabolites in dry pet food samples were developed using an acetonitrile-based extraction and an ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) method. The proposed method showed satisfactory validation results according to Commission Decision 2002/657/EC. Average recoveries from 72 to 108% were obtained for all studied mycotoxins, and the intra-/inter-day precision were below 9 and 14%, respectively. Results showed mycotoxin contamination in 99% of pet food samples (n = 89) at concentrations of up to hundreds µg/kg, with emerging Fusarium mycotoxins being the most commonly detected mycotoxins. All positive samples showed co-occurrence of mycotoxins with the simultaneous presence of up to 16 analytes per sample. In the retrospective screening, up to 54 fungal metabolites were tentatively identified being cyclopiazonic acid, paspalitrem A, fusaric acid, and macrosporin, the most commonly detected analytes.

Comparison of different culture media for mycological evaluation of commercial pet food

The choice of a culture media to proceed a mycological analysis of food is extremely important to guarantee the reliability of the analysis. The medium should allow an excellent recovery of fungal species present in the food at the same time that it is necessary to avoid bacterial development. Thus the real microbial ecology will be reflected in the results. The efficacy of three media for fungal isolation and quantification (potato dextrose agar, dichloran rose of bengal and chloramphenicol agar and dichloran glycerol 18% agar) was compared for analysis of 54 samples of dry commercial pet food (34 for dogs and 20 for cats). Fungi were present in 74% of samples and 23 genera were isolated and identified. Aspergillus sp. and Aspergillus niger were respectively the most frequent genera and species isolated, whatever the culture medium selected to proceed the analysis. Dichloran glycerol 18% agar was the medium that presented the best results considering both the quantity and variety of isolated fungi. Comparing the results obtained in different media, it was observed that the fungi recovered can vary according to the selected culture medium. Eurotium was the genus that presented the biggest difference in occurrence among the media where samples were cultivated to enumeration in this study. Therefore, the utilization of specific media, selected according to the characteristics of the food to be analyzed (specially water activity) allow a better visualization of the presence of food spoilage fungi.

Parabens and Their Metabolites in Pet Food and Urine from New York State, United States.

The exposure of pets, such as dogs and cats, to a wide range of chemicals present in the indoor environment and the concomitant increase in noninfectious diseases in these companion animals are a concern. Nevertheless, little is known about the sources and pathways of exposure to chemicals in pets. In this study, we determined the concentrations of parabens in commercially available cat and dog foods as well as in urine samples from these pets collected from the Albany area of the state of New York in the United States. Parabens, especially methyl paraben (MeP), and their metabolites were found in all pet food and urine samples. The mean concentrations of total parabens (i.e., sum of parabens and their metabolites) in dog ( n = 23) and cat ( n = 35) food were 1350 and 1550 ng/g fresh wt, respectively. Dry food contained higher concentrations of parabens and their metabolites than did wet food, and cat food contained higher concentrations of target chemicals than did dog food. The mean concentrations of total parabens found in dog ( n = 30) and cat ( n = 30) urine were 7230 and 1040 ng/mL, respectively. In both pet food and urine, MeP (among parabens) and 4-hydroxy benzoic acid (4-HB) (among metabolites) were the dominant compounds. The metabolites of parabens accounted for ∼99% (∼99.1% in food and ∼98.9% in urine) of the total concentrations in both food and urine. The profiles of parabens and their metabolites in the urine of dogs and cats varied. In addition to diet, other sources of paraben exposures were found for dogs, whereas, for cats, the majority of exposures was identified as related to diet.

Raw pet food as a risk factor for shedding of extended-spectrum beta-lactamase-producing Enterobacteriaceae in household cats.

BackgroundClose contact between pets and owners provides the opportunity for transmission of antimicrobial resistant organisms like extended-spectrum beta-lactamase (ESBL)/AmpC beta-lactamase (AmpC)-producing Enterobacteriaceae, posing a risk to public health.ObjectivesTo investigate whether raw feed is a risk factor for household cats to shed ESBL-producing Enterobacteriaceae, a cohort study was designed. Additionally, raw and non-raw commercial pet food products were screened for the presence of ESBL-producing Enterobacteriaceae.MethodsWeekly fecal samples of 17 cats in the control group and 19 cats in the exposed group were collected for three weeks and analyzed for the presence of ESBL-producing Enterobacteriaceae. Questionnaires were obtained to determine additional risk factors. Fecal samples were cultured on MacConkey agar supplemented with 1 mg/L cefotaxime. PCR and sequence analysis was used for screening for ESBL genes in suspected isolates. Pet food samples were cultured in LB broth supplemented with 1 mg/L cefotaxime and processed as described above.ResultsIn the cohort study, ESBL-producing bacteria were isolated from 3 of 51 (5.9%) samples in the control group compared to 37 of 57 (89.5%) samples in the exposed group. A significant association was found between ESBL shedding and feeding raw pet food products (OR = 31.5). No other risk factors were identified in this study. ESBL-producing Enterobacteriaceae were isolated from 14 of 18 (77.8%) raw pet food products and 0 of 35 non-raw pet food products.ConclusionsThis study shows a strong association between shedding of ESBL-producing bacteria in household cats and feeding raw pet food. Raw pet food was often contaminated with ESBL-producing Enterobacteriaceae.

Anthropogenic and Naturally Produced Brominated Phenols in Pet Blood and Pet Food in Japan.

Present study determined concentrations and residue patterns of bromophenols (BPhs) in whole blood samples of pet cats and pet dogs collected from veterinary hospitals in Japan. BPhs concentrations were higher in cat blood than in dog blood, with statistically insignificant differences (p = 0.07). Among the congeners, 2,4,6-tribromophenol (TBPh) constituted the majority of BPhs (>90%) detected in both species. Analysis of commercial pet food to estimate exposure routes showed that the most abundant congener in all pet food samples was 2,4,6-TBPh, accounting for >99% of total BPhs. This profile is quite similar to the blood samples of the pets, suggesting that diet might be an important exposure route for BPhs in pets. After incubation in polybrominated diphenyl ether (PBDE) mixtures (BDE-47, BDE-99 and BDE-209), 2,4,5-TBPh was found in dog liver microsomes but not in cat liver microsomes, implying species-specific metabolic capacities for PBDEs. Formation of 2,4,5-TBPh occurred by hydroxylation at the 1' carbon atom of the ether bond of BDE-99 is similar to human study reported previously. Hydroxylated PBDEs were not detected in cats or dogs; therefore, diphenyl ether bond cleavage of PBDEs can also be an important metabolic pathway for BPhs formation in cats and dogs.

Mercury concentrations in wet and dry cat and dog food

Given that mercury (Hg) concentrates in fish, and this is an important ingredient in pet food, we hypothesized that Hg concentrations could be of concern. To address this hypothesis, total Hg concentrations were measured in a variety of brands of cat (n=47) and dog (n=54) food. Since most of the Hg in fish is methylmercury, we assume that this is the form in the pet food. However, this still needs to be tested. Mercury concentrations ranged from 1 to 604ngg−1. There are no standards for pet food, so values were compared to available consumption advisories: 300–1000ngg−1 for humans, 30ngg−1 for kingfishers (fish eating birds), small mammals (70ngg−1), and river otters (100ngg−1). Thirty one of the pet food samples had concentrations >30ngg−1, and 14>100ngg−1. More studies are necessary to understand the health implications of Hg concentrations observed.

Development and Validation of an ED-XRF Method for the Fast Quantification of Mineral Elements in Dry Pet Food Samples

A simple and fast method for the quantification of a series of macro elements (Na, Mg, P, Cl, K and Ca) and trace elements (Mn, Fe, Cu and Zn) by Energy Dispersive X-Ray Fluorescence (ED-XRF) was developed and validated using samples of commercial dry pet foods. All samples were systematically analyzed by reference methods (i.e. Potentiometry for chloride and Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) for other elements) and by ED-XRF. A calibration set of 33 samples was selected to uniformly cover the concentration ranges of each element and their reference method values were used to calibrate the ED-XRF device. A second set (the validation set) was composed of 46 other samples, which were analyzed as unknowns. During this validation step, the elemental concentrations obtained by ED-XRF were systematically evaluated against those obtained from the reference methods. Using robust statistics, for the 10 investigated analytes, the bias between both methods was found to be not significantly different from 0 and the relative uncertainties RSD(u) were found to be lower than 15 %. This study demonstrated that ED-XRF is a fast and reliable method for minerals quantification in dry pet foods.

Development and inter-laboratory study of a method for quantifying zearalenone in pet foods

An analytical method for quantifying zearalenone (ZEA) in pet foods using a liquid chromatograph-atmospheric pressure chemical ionization-mass spectrometer (LC-APCI-MS) was developed, and an inter-laboratory study was conducted. ZEA was extracted from pet food samples with aqueous acetonitrile. The extract was purified using a multifunctional column, MultiSep 226 Aflazon+, and analysed with LC-APCI-MS. The limit of quantification of ZEA by this method was estimated to be 0.2 mg/kg for dry and semi-dry pet foods, and 0.1 mg/kg for wet pet food. The calibration curve of ZEA for this method showed linearity in the range of 0.1-10 ng of ZEA (0.01-1.0 µg/ml, 0.04-4.0 mg/kg matrix). The mean recoveries, repeatabilities, reproducibilities, and the HorRats for ZEA from the inter-laboratory validation study were 99.0-102%, 2.2-3.0%, 5.6-6.6%, and 0.33-0.36, respectively.

Extruded Pet Food Development from Meat Byproducts using Extrusion Processing and its Quality Evaluation

The studies were carried out to development and quality evaluation of extruded pet food by utilization of buffalo meat byproducts like livers, trims and agro wastes namely sorghum, oat and corn flour. The quality of the extruded pet food was evaluated on the basis of qualities characteristics namely pH, fat content, protein content, ash content, and TBA number. Protein content and fat content of fresh pet food were found in the following ranges 15.84% and 10.64% respectively. The pH of extruded pet food was significantly decreased. The ash content, TBA number and pH content were 2.43%, 0.605 mg/kg and 6.29% in fresh condition. During ambient storage pH values was found to decrease consistently. Protein content was found to decrease significantly. The Sorghum, oat and corn flour incorporation, significantly affected on quality of extruded pet food samples.

Identification of Aflatoxins and Ochratoxin A in Selected Imported Pet Food

The current study was conducted to analyze the aflatoxins (AF i.e. AFB1, AFB2, AFG1 AFG2) and ochratoxin A (OTA) in imported pet food. A total of five hundred and ten commercially available imported pet food samples of cat (solid = 240, semi-solid = 90) and dog (solid = 150, semi-solid = 30) were collected from retailers and analyzed by chromatographic technique i.e. HPTLC. Results revealed 45.83% (mean, 3.90 ppb) and 18% (mean, 4.83 ppb) of AFB1 incidence in solid pet foods of cats and dogs, respectively. However, lower levels i.e. 8.88% (mean, 4.60ppb) and 6.66% (mean, 2.80ppb) of AFB1 were observed for semi-solid food samples of cat and dog, respectively. Aflatoxin B2 was found in solid cat food only with an incidence of 12.5% (mean, 0.89 ppb). About 35.33% (mean, 4.5 ppb) and 26.66% (mean, 2 ppb) of OTA were observed in solid and semi-solid dog foods respectively. Similarly, the trend of OTA in cat foods was 15% (mean, 3.87 ppb) and 13.13% (mean, 1.0 ppb) for solid and semisolid foods. Furthermore, co-contamination of AF and OTA were observed in 33.33% and 41.60% samples of dog and cat foods, respectively. It was concluded that natural incidence of mean contaminations was below than European Commission (EC) legislation i.e. 20 ppb and 10 ppb for AF and OTA, respectively. However, co-occurrence of mycotoxins in pet food may exert synergistic deleterious effects even at levels far below the regulatory limits.

Determination of moulds and mycotoxins in dry dog and cat food using liquid chromatography with mass spectrometry and fluorescence detection

In this study moulds and 12 mycotoxins in dry pet food samples (25 for dogs and 24 for cats) were determined. Primary moulds identified were Aspergillus, Mucor and Penicillium, found in 55% of the samples. Deoxynivalenol and zearalenone (ZEN) were detected in all samples with mean respective concentrations being 97.3 and 38.3 µg kg−1 in cat food and 114 and 20.1 µg kg−1 in dog food. T-2 and HT-2 toxins were present in 88% and 84% of the samples, respectively. Two samples contained fumonisins, with a maximum concentration of 108 µg kg−1. Aflatoxin B1 and ochratoxin A were detected in 8% and 45% of the samples, respectively. The measured mould and mycotoxin levels were consistent with results obtained by other studies. However, potential exposure to relatively high concentrations of an oestrogen mycotoxin as is ZEN, especially when in combination with other mycotoxins, needs attention.

The Effects of Cooking Process and Meat Inclusion on Pet Food Flavor and Texture Characteristics.

Simple SummaryThe results of this research indicate that processing (baked vs. extruded) plays an important role in determining pet food product texture. In addition, raw ingredients (fresh meat vs. meal-based) did not consistently affect product sensory characteristics. These results may help pet food technologists better understand factors that affect palatability.The pet food industry is an important portion of the food and feed industries in the US. The objectives of this study were (1) to determine cooking method (baking or extrusion), meat inclusion (0 or 20%), and extrusion thermal to mechanical energy ratios (low, medium, and high) effects on sensory and volatile properties of pet foods, and (2) to determine associations among sensory and volatile characteristics of baked and extruded pet foods. Descriptive sensory analysis and gas chromatography-mass spectrometry were used to analyze the pet food samples. It was found that baked samples were lighter in color (2.0–2.6 baked vs. 3.5–4.3 extruded, color intensity scale 0–15), and had lower levels of attributes that indicated rancidity (i.e., fishy flavor; 0.3–0.6 baked, 0.6–1.5 extruded, scale 0–15), whereas extruded pet foods were more cohesive in mass, more friable, hard, and crisp, but less powdery than baked samples. Fresh meat inclusion tended to decrease bitterness and increase fishy flavor and cohesiveness of pet foods. High thermal to mechanical energy ratio during extrusion resulted in less musty and more porous kibbles. The main volatile compounds included aldehydes, such as hexanal and heptanal, ketones, and alcohols. Extruded samples did not contain methylpyrazine, while baked samples did not contain 2-butyl furan. Future studies should consider evaluating the relationship between sensory results and animal palatability for these types of foods.

Validation of the ANSR Salmonella method for detection of Salmonella spp. in a variety of foods. Performance Tested Method 061203.

This study represents a proposal to extend the matrix claims for the ANSR Salmonella test, Performance Tested Method 061203. The test is based on the nicking enzyme amplification reaction (NEAR) isothermal nucleic acid amplification technology. The assay platform features simple instrumentation, minimal labor, and following a single-step 16-24 h enrichment (depending on sample type), an extremely short assay time of 30 min including sample preparation. Detection is real-time using fluorescent molecular beacon probes. ANSR Salmonella was originally validated for detection of Salmonella spp. in chicken carcass rinse, raw ground turkey, raw ground beef, hot dogs, and oat cereal, and on stainless steel, plastic, sealed concrete, ceramic tile, and rubber surfaces. The matrixes tested in this study include pet food, ice cream, soy flour, raw almonds, peanut butter, spinach, black pepper, raw frozen shrimp, cocoa powder, and pasteurized dried egg. In unpaired comparative testing there were no statistically significant differences in the number of positive results obtained with the ANSR and the reference culture methods. Enrichment for 16 h was effective for all commodities tested except ice cream, black pepper, dried pasteurized egg, and 375 g samples of dry pet food, for which enrichment for 24 h is indicated.

Multivariate optimization of an analytical method for the analysis of dog and cat foods by ICP OES

Experimental design methodology was used to optimize an analytical method for determination of the mineral element composition (Al, Ca, Cd, Cr, Cu, Ba, Fe, K, Mg, Mn, P, S, Sr and Zn) of dog and cat foods. Two-level full factorial design was applied to define the optimal proportions of the reagents used for microwave-assisted sample digestion (2.0molL−1 HNO3 and 6% m/v H2O2). A three-level factorial design for two variables was used to optimize the operational conditions of the inductively coupled plasma optical emission spectrometer, employed for analysis of the extracts. A radiofrequency power of 1.2kW and a nebulizer argon flow of 1.0Lmin−1 were selected. The limits of quantification (LOQ) were between 0.03μgg−1 (Cr, 267.716nm) and 87μgg-1 (Ca, 373.690nm). The trueness of the optimized method was evaluated by analysis of five certified reference materials (CRMs): wheat flour (NIST 1567a), bovine liver (NIST 1577), peach leaves (NIST 1547), oyster tissue (NIST 1566b), and fish protein (DORM-3). The recovery values obtained for the CRMs were between 80±4% (Cr) and 117±5% (Cd), with relative standard deviations (RSDs) better than 5%, demonstrating that the proposed method offered good trueness and precision. Ten samples of pet food (five each of cat and dog food) were acquired at supermarkets in Aracaju city (Sergipe State, Brazil). Concentrations in the dog food ranged between 7.1mgkg−1 (Ba) and 2.7gkg−1 (Ca), while for cat food the values were between 3.7mgkg−1 (Ba) and 3.0gkg−1 (Ca). The concentrations of Ca, K, Mg, P, Cu, Fe, Mn, and Zn in the food were compared with the guidelines of the United States’ Association of American Feed Control Officials (AAFCO) and the Brazilian Ministry of Agriculture, Livestock, and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento—MAPA).

ペットフード中リン,鉄,カルシウム,マグネシウム,亜鉛,マンガンおよび銅の分析におけるICP発光分析法の有用性

ペットフード中リン,鉄,カルシウム,マグネシウム,亜鉛,マンガンおよび銅の分析におけるICP発光分析法の有用性