Species In Food Research Articles

Prevalence of Non-typhoidal Salmonella Species in Food and Stool Samples in Port Harcourt, Rivers State, Nigeria

Aim: To assess the prevalence of Non-Typhoidal Salmonella spp isolated from food and stool samples in Port Harcourt. Study Design: This was a cross-sectional study with simple randomized sampling. Methodology: In this study, 210 stool samples and 210 food samples collected from December 2022 to November 2023 were tested for Salmonella using standard bacteriological and biochemical tests. The Salmonella species were isolated from the samples using Salmonella-Shigella agar (SSA), and Bismuth Sulfite Agar (BSA) after pre-enrichment and enrichment methods had been carried out using peptone water and Selenite F Broth after which biochemical tests were carried out for further identification. Data collected was analyzed with Graph pad prism version 8. Results: The prevalence and distribution of Salmonella were presented in frequencies and percentages with all analysis done at a 95% confidence interval and P-values less than .05 were considered significant. From chi-square analysis there was a 3.3% prevalence rate in food samples in comparison to stool samples that had a 2.4% prevalence (P value = .56). A higher prevalence was also reported in the female subjects (3.7%) compared to the male subjects (1.0%) (P value = .19). There was a statistically significant difference in relation to the age groups with the ‘above 50’ and ‘0 – 10’ age groups having a higher prevalence (11.1% and 10% respectively) compared to other age groups (P value = .02). For the food samples, samples in the chicken category had the highest prevalence (8.7%) (P value = 0.11). Conclusion: This study reports a relatively lower prevalence of Non-Typhoidal Salmonella species at 2.9% with the age, education and occupation of the subjects being significantly associated (P value < .05) with the prevalence of the infection. Health promotion and appropriate surveillance system should be put in place to continually reduce the burden of this disease.

High-resolution live cell imaging to define ultrastructural and dynamic features of the halotolerant yeast Debaryomyces hansenii.

Although some budding yeasts have proved tractable and intensely studied models, others are more recalcitrant. Debaryomyces hansenii, an important yeast species in food and biotechnological industries with curious physiological characteristics, has proved difficult to manipulate genetically and remains poorly defined. To remedy this, we have combined live cell fluorescent dyes with high-resolution imaging techniques to define the sub-cellular features of D. hansenii, such as the mitochondria, nuclei, vacuoles and the cell wall. Using these tools, we define biological processes like the cell cycle, organelle inheritance and various membrane trafficking pathways of D. hansenii for the first time. Beyond this, reagents designed to study Saccharomyces cerevisiae proteins were used to access proteomic information about D. hansenii. Finally, we optimised the use of label-free holotomography to image yeast, defining the physical parameters and visualising sub-cellular features like membranes and vacuoles. Not only does this work shed light on D. hansenii but this combinatorial approach serves as a template for how other cell biological systems, which are not amenable to standard genetic procedures, can be studied.

Risk assessment of small organoarsenic species in food.

The European Commission asked EFSA for a risk assessment on small organoarsenic species in food. For monomethylarsonic acid MMA(V), decreased body weight resulting from diarrhoea in rats was identified as the critical endpoint and a BMDL10 of 18.2 mg MMA(V)/kg body weight (bw) per day (equivalent to 9.7 mg As/kg bw per day) was calculated as a reference point (RP). For dimethylarsinic acid DMA(V), increased incidence in urinary bladder tumours in rats was identified as the critical endpoint. A BMDL10 of 1.1 mg DMA(V)/kg bw per day (equivalent to 0.6 mg As/kg bw per day) was calculated as an RP. For other small organoarsenic species, the toxicological data are insufficient to identify critical effects and RPs, and they could not be included in the risk assessment. For both MMA(V) and DMA(V), the toxicological database is incomplete and a margin of exposure (MOE) approach was applied for risk characterisation. The highest chronic dietary exposure to DMA(V) was estimated in 'Toddlers', with rice and fish meat as the main contributors across population groups. For MMA(V), the highest chronic dietary exposures were estimated for high consumers of fish meat and processed/preserved fish in 'Infants' and 'Elderly' age class, respectively. For MMA(V), an MOE of ≥ 500 was identified not to raise a health concern. For MMA(V), all MOEs were well above 500 for average and high consumers and thus do not raise a health concern. For DMA(V), an MOE of 10,000 was identified as of low health concern as it is genotoxic and carcinogenic, although the mechanisms of genotoxicity and its role in carcinogenicity of DMA(V) are not fully elucidated. For DMA(V), MOEs were below 10,000 in many cases across dietary surveys and age groups, in particular for some 95th percentile exposures. The Panel considers that this would raise a health concern.

Plain Language Summary of the Risk assessment of small organoarsenic species in food.

Plain Language Summary of the Risk assessment of small organoarsenic species in food.

Pharmacological and Biochemical activities of plantago major L

Throughout human history, natural remedies have been sought to treat diseases. The therapeutic wounds of plants are accepted worldwide as a result of many studies and research. Medicinal plants have started to be used in the pharmaceutical sector due to the chemical compounds contained in their structures. One of the potential plants that can be used in traditional medicine is the broadleaf plantain, white man's footprint, waybread, or greater plantain. Scientifically known as Plantago major, it is a wild plant belonging to the Plantaginaceae family that can reach a height of about 15 cm. Plantago major leaves have been used for centuries almost everywhere in the world as a wound healer and in the treatment of many diseases other than wound healing. Among them are treatments for skin, respiratory organs, digestive organs, reproduction, circulatory diseases, infections, and cancer. It is also used as a decongestant and analgesic. Plantago major contains biologically active compounds such as polysaccharides, lipids, caffeic acid derivatives, flavonoids, iridoid glycosides, and terpenoids. Alkaloids and some organic acids have also been detected. There are several biological activities from plant extracts, including wound healing activity, anti-inflammatory, analgesic, antioxidant, weak antibiotic, immune modulating, and antiulcerogenic activity. The widespread use of Plantago species in food and traditional medicine has attracted the attention of researchers looking for active principles and mechanisms of action. However, more studies are needed to better prove the medical applications, phytochemical properties, and pharmacological properties of this breed.

Graphite/Aluminum oxide/polylactic acid composite material: A valuable strategy for additively manufacturing cheap and improved electrochemical platforms for sensing sulfamethoxazole in honey samples

Composite materials with properties aimed at the additive manufacturing of affordable electrochemical sensors have received special attention in the scientific scenario. For this reason, we proposed a new composite material based on alumina oxide (Al2O3) and graphite (Gpt) dispersed in polylactic acid (PLA) biopolymer. Various proportions between the materials were studied, and a better compromise between printability and electrochemical performance was obtained using Gpt/Al2O3/PLA (30:10:60% w/w). The electrodes were manufactured using a 3D pen, a portable, user-friendly, and low-cost tool. Characterizations by Raman and infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy indicated that Gpt and Al2O3 were successfully incorporated into the PLA matrix. Preliminary studies using species with well-known electrochemical behavior revealed that Al2O3 positively impacts the electrochemical response of the sensor. As a proof of concept, sulfamethoxazole (SMZ), a low-cost antibiotic widely used in beekeeping practices, was selected as the target analyte, and a simple, fast, and selective method using square wave voltammetry was proposed. Using the 3D-printed Gpt/Al2O3/PLA electrode, a wider linear range (2.0 to 40.0 μmol L−1), a 6.5-fold increase in sensitivity, limits of detection (LOD = 0.4 μmol L−1) and quantification (LOQ = 1.2 μmol L−1) were achieved compared to the Al2O3-free electrode (Gpt/PLA). In addition, the proposed sensor was selective against other antibiotics commonly used in beekeeping practices. Three honey samples were analyzed after simple dilution in 0.12 mol L−1 Britton-Robinson buffer, pH 7.0 (background electrolyte), and recoveries close to 100% as well as statistically comparable results from chromatographic analysis certified the accuracy and reliability of the analysis. The proposed approach is innovative and valuable in contributing to the advancement of additive manufacturing in electrochemical sensing, especially in the on-site analysis of antibiotic species in food, a public health challenge.

Machine-Learning-Assisted Aggregation-Induced Emissive Nanosilicon-Based Sensor Array for Point-of-Care Identification of Multiple Foodborne Pathogens.

How timely identification and determination of pathogen species in pathogen-contaminated foods are responsible for rapid and accurate treatments for food safety accidents. Herein, we synthesize four aggregation-induced emissive nanosilicons with different surface potentials and hydrophobicities by encapsulating four tetraphenylethylene derivatives differing in functional groups. The prepared nanosilicons are utilized as receptors to develop a nanosensor array according to their distinctive interactions with pathogens for the rapid and simultaneous discrimination of pathogens. By coupling with machine-learning algorithms, the proposed nanosensor array achieves high performance in identifying eight pathogens within 1 h with high overall accuracy (93.75-100%). Meanwhile, Cronobacter sakazakii and Listeria monocytogenes are taken as model bacteria for the quantitative evaluation of the developed nanosensor array, which can successfully distinguish the concentration of C. sakazakii and L. monocytogenes at more than 103 and 102 CFU mL-1, respectively, and their mixed samples at 105 CFU mL-1 through the artificial neural network. Moreover, eight pathogens at 1 × 104 CFU mL-1 in milk can be successfully identified by the developed nanosensor array, indicating its feasibility in monitoring food hazards.

Halophilic lactic acid bacteria - Play a vital role in the fermented food industry.

Halophilic lactic acid bacteria have been widely found in various high-salt fermented foods. The distribution of these species in salt-fermented foods contributes significantly to the development of the product's flavor. Besides, these bacteria also have the ability to biosynthesize bioactive components which potentially apply to different areas. In this review, insights into the metabolic properties, salt stress responses, and potential applications of these bacteria have been have been elucidated. The purpose of this review highlights the important role of halophilic lactic acid bacteria in improving the quality and safety of salt-fermented products and explores the potential application of these bacteria.

Coordination of prophage and global regulator leads to high enterotoxin production in staphylococcal food poisoning-associated lineage.

The importance of this study lies in its unveiling of a molecular regulatory mechanism associated with the most important food poisoning toxin and the evolution of Staphylococcal food poisoning (SFP)-associated clone. SFP is primarily caused by Staphylococcus aureus, with Staphylococcal enterotoxin A (SEA) being commonly involved in many cases. Thus, SEA has been recognized as a major toxin type. However, despite almost a century since its discovery, the complete mechanism of SEA production is as yet unknown. In this study, we analyzed an SEA-producing SFP clone isolated in East Asia and discovered that this strain, besides acquiring the high SEA-producing phage, exhibits remarkably high SEA production due to the low activity of SarS, an intrinsic regulatory factor. This is the first report documenting the evolution of the SFP clone through the coordinated action of exogenous mobile genetic factors and endogenous regulators on this notorious toxin.

Detecting Fasciola hepatica and F. gigantica microRNAs using loop-mediated isothermal amplification (LAMP)

Fascioliasis is a parasitic infection typically caused by two common parasites of class Trematodo, genus Fasciola, named Fasciola hepatica and F. gigantica. The widespread appearance of these species in water and food makes fascioliasis become a global zoonotic disease that affects 2.4 million people in more than 75 countries worldwide. Typically, F. hepatica and F. gigantica can be recognized with parasitological techniques to detect Fasciola spp. eggs, immunological techniques to detect worm-specific antibodies, or molecular techniques for instance polymerase chain reactions to detect parasitic genomic DNA. Recently, miRNAs have been recognised a key regulator and potential diagnostic biomarkers of diseases, including parasitic infection. An isothermal PCR called LAMP (loop-mediated isothermal amplification) is rapid, sensitive, and this amplification is very extensive, making it well-suited for field diagnostics. LAMP reaction for miRNA detection has been introduced and is able to detect miRNA in the range between 1.0amol and 1.0pmol, showing high selectivity to differentiate one miRNA sequence from others. Here, we introduced a modified LAMP to detect a typical miRNA of both F. hepatica and F. gigantica. Our method does not demand an initial heating step and the reactions have a high sensitivity even 1,000 times higher in comparison to that reported in previous studies. These results create a promising technique basis for some novel and simple device to diagnose fascioliasis and other parasitic diseases at point-of-care.

Importance of Elemental Chemical Speciation Studies in Enriched Food: Nutritional Quality, Toxicity, and Economic Improvement

For several reasons, mainly cost and local productivity, the world population does not have access to a balanced diet that contains all the macro and micronutrients necessary to maintain physiological functions for a healthy life. Nutritional education, supplementation, and consuming enriched (or fortified) foods appear as alternatives to supply daily demands and minimize malnutrition. Adding essential elements as salts (e.g., iron, calcium, and zinc) to ready-to-eat processed foods, such as milk, flour, and juices is already adopted in several countries. The choice of the compound to be added, as well as the transport vehicle (foods), must be very well evaluated since the cost, long-term consumption, and bioavailability of the added chemical species are imperative to ensure the nutritional quality of enriched food.1 Another alternative to produce enriched foods is cultivating an enriched medium (Figure 1), adding essential elements to soil or in nutritive solution (hydroponic procedure), irrigating leaves, or immersing seeds.2 In this case, the chemical species used to the enrich food must be absorbed, translocated, and accumulated in the edible part.2 Studies have shown that the iron enrichment of adzuki beans using iron nitrate or iron chloride was unsuccessful since iron inorganic species interact strongly with the antinutrients (tannins or phytates) present in the roots, forming insoluble complexes and preventing their translocation.3 Alternatives found to overcome this obstacle were enrichment by applying iron complexes with EDTA (ethylenediaminetetra-acetic acid)3 or iron nanoparticles, mainly encapsulated.4 The nanoparticle application has been gaining prominence in agriculture, aiming to carry fertilizer, pesticides, and nutrients to stimulate plant growth and increase macro and micronutrient availability and absorption efficiency.5,6 Besides the interaction between essential elements with antinutrients, evaluating the competition between elemental species is important, because synergistic or antagonistic effects can be observed. In both cases, chemical species must interact with other components present in food or cultivation medium, altering its chemical composition when compared to food cultivated in conventional conditions. The antagonistic effect between selenium and mercury was observed in edible mushrooms, while the synergistic effect was observed with lead and selenium.7,8 Finally, it must be evaluated if the enrichment promotes the production of non-bioavailable or toxic species. Regardless of the food enrichment strategy, it is important to highlight the need to identify and quantify the elemental chemical species in the enriched foods by chemical speciation analysis. In the Figure 1 is shown examples of elemental chemical species; they can differ according to their oxidation states, inorganic forms, and organometallic or isotopic composition.9 For chemical speciation studies, initial fractionation steps (e.g., extraction procedures) are carried out; subsequently, chromatographic, or non-chromatographic methods can be used to identify/determine the chemical species. The hyphenation (Figure 1) between separation techniques, mainly chromatography, with high sensitivity detectors, such as inductively coupled plasma mass spectrometry (ICP-MS), is commonly applied.9-11 Nonetheless, extremely creative procedures used in non-chromatographic chemical speciation, working only with chemical reactions and solubility differences, can also be applied to determine chemical species. Non-chromatographic strategies were applied for iron (reaction with hydroxylamine and precipitation with trichloroacetic acid and HCl) and selenium (cloud point extraction) speciation in enriched adzuki sprouts.3 In summary, food enrichment success is closely associated with chemical speciation studies since there are chemical species that will be absorbed in a cultivation medium, as well as the chemical species that are formed during translocation and accumulation, which must be in bioavailable forms, in order to act on the different metabolic systems of the human body, including remedying prevalences. In this scenario, it is imperative to go beyond determining the total concentration of essential elements, since quantifying their species will provide information regarding essentiality and toxicity. Finally, the formation of bioavailable chemical species will add nutritional quality and, consequently, economic benefits that are so essential for countries with specific prevalences to combat in a predominantly agricultural economy.

Characterisation and quantification of phenolic, anthocyanidin and terpene species in plant foods and plant food-based complementary products with antioxidant and neuroprotective properties.

Phytochemicals, including phenolic compounds and terpenes, are of interest for the treatment and prevention of conditions with oxidative stress, inflammatory and neurodegenerative pathologies. Certain plant foods have shown beneficial effects for the brain; however, the specific phenolic and terpene species in these foods are unclear. The present study aimed to characterise and quantify the phenolic, anthocyanidin and terpene species in six plant foods (Queen Garnet plum (QGP, Prunus salicina); black pepper (BPF, Piper nigrum); clove (CF, Syzygium aromaticum); elderberry (EF, Sambucus nigra); lemon balm (LBF, Melissa officinalis); and sage (SF, Salvia officinalis)) and six plant food-based complementary products (clove (CC), elderberry (EC), lemon balm (LBC), and sage (SC), plus two blends (Astragalus membranaceus and lemon balm-rich, WC and R8)). The relationships between the concentration of phytochemical species in these samples and their antioxidant capacities (i.e. oxygen and nitrogen free radical scavenging, Cu2+ and Fe2+ chelating capacities, and the ability to prevent H2O2-induced oxidative stress in neuroblast-like SH-SY5Y cells, in vitro) were also examined. WC had the highest concentration of phenolics, followed by QGP, EF, CC and CF. BPF had the highest total terpene concentration followed by CC, CF and SF. Correlations between certain compounds and antioxidant capacity were demonstrated. The results provide insight into the potential functional capabilities of species of phenolics and terpenes. Understanding the phytochemical profile of plant foods and their correlations may be important in understanding their potential therapeutic benefits for brain health.

Development of ion torrent-based targeted next-generation sequencing panel for identification of animal species in pet foods

Manufacturers may intentionally or unintentionally incorporate ingredients not specified on the label of canned pet foods. Including any unacknowledged ingredients in a food product is considered food fraud or misbranding. Contamination of pet foods may occur in the processing of the foods, including potential cross-contamination in packaging facilities.Of the methods available to identify meat species in food products, Sanger sequencing and several next-generation sequencing methods are available, but there are limitations including the number of targets analyzed at a time and the method specificity. In this study, we developed a targeted next-generation sequencing panel to detect meat species in canned pet foods using Ion Torrent technology.The panel contains multiple primers targeting mitochondrial genes from as many as 27 animal species, of which 7 major animal species were validated. The meat species targets could be identified from samples spiked with as low as 0.01% w/w of the contaminating meat species in a vegetarian food matrix material. Targeted NGS in the current study enriches species-specific multiple target areas in the mitochondrial genome of the target material, which gives high accuracy in the sequencing results.

Technique for the identification of insect species in processed foods based on three short DNA sequences

For pest control, it is necessary to identify insect species in food. However, it is difficult to identify the insect species in processed food based on their morphological characteristics owing to deformation or fragmentation. DNA sequence-based identification is useful not only to corroborate morphological identification, but also as an alternative identification approach. Therefore, markers are required to obtain the target specific amplicons from insect DNA sequences fragmented by food processing. We developed a DNA sequence-based insect species identification technique that combined two markers in the cytochrome oxidase subunit I (COI) region and one marker in the 16S ribosomal RNA (rRNA) region, with amplicons up to 200 bp in size. The identification results from this technique were consistent with those from the morphological identification of 89% of the 38 insect samples selected from seven orders. This technique identified the insect species in insect samples recovered from model food that were heat-treated at 118 °C for 18 min.

Foodborne Clostridioides Species: Pathogenicity, Virulence and Biocontrol Options.

Clostridioides species possess many virulence factors and alarming levels of muti-drug resistance which make them a significant risk to public health safety and a causative agent of livestock disease. Clostridioides result in serious systemic and gastrointestinal diseases such as myonecrosis, colitis, food poisoning and gastroenteritis. As foodborne pathogens, Clostridioides species are associated with significant incidences of morbidity and mortality where the application of broad-spectrum antibiotics predisposes patients to virulent Clostridioides colonisation. As part of the One Health approach, there is an urgent need to eliminate the use of antibiotics in food production to safeguard animals, humans and the environment. Alternative options are warranted to control foodborne pathogens at all stages of food production. Antimicrobial peptides and bacteriophages have demonstrated efficacy against Clostridioides species and may offer antimicrobial biocontrol options. The bacteriocin nisin, for example, has been implemented as a biopreservative for the control of Listeria, Staphylococcus and Clostridia species in food. Bacteriophage preparations have also gained recognition for the antibacterial action against highly virulent bacterial species including foodborne pathogens. Studies are warranted to mitigate the formulation and administration limitations associated with the application of such antimicrobials as biocontrol strategies. This review outlines foodborne Clostridioides species, their virulence factors, and potential biocontrol options for application in food production.

Research Progress of Selenium-Enriched Foods.

Selenium is an essential micronutrient that plays a crucial role in maintaining human health. Selenium deficiency is seriously associated with various diseases such as Keshan disease, Kashin-Beck disease, cataracts, and others. Conversely, selenium supplementation has been found to have multiple effects, including antioxidant, anti-inflammatory, and anticancer functions. Compared with inorganic selenium, organic selenium exhibits higher bioactivities and a wider range of safe concentrations. Consequently, there has been a significant development of selenium-enriched foods which contain large amounts of organic selenium in order to improve human health. This review summarizes the physiological role and metabolism of selenium, the development of selenium-enriched foods, the physiological functions of selenium-enriched foods, and provides an analysis of total selenium and its species in selenium-enriched foods, with a view to laying the foundation for selenium-enriched food development.

A Critical Overview of HPLC-MS-Based Lipidomics in Determining Triacylglycerol and Phospholipid in Foods.

With the current advancement in mass spectrometry (MS)-based lipidomics, the knowledge of lipidomes and their diverse roles has greatly increased, enabling a deeper understanding of the action of bioactive lipid molecules in plant- and animal-based foods. This review provides in-depth information on the practical use of MS techniques in lipidomics, including lipid extraction, adduct formation, MS analysis, data processing, statistical analysis, and bioinformatics. Moreover, this contribution demonstrates the effectiveness of MS-based lipidomics for identifying and quantifying diverse lipid species, especially triacylglycerols and phospholipids, in foods. Further, it summarizes the wide applications of MS-based lipidomics in food science, such as for assessing food processing methods, detecting food adulteration, and measuring lipid oxidation in foods. Thus, MS-based lipidomics may be a useful method for identifying the action of individual lipid species in foods.

Extraction and determination of mercury from spring water, beverage and rice samples using combined microwave‐assisted cloud point and dispersive‐solid phase extraction in micellar media

AbstractThe determination of inorganic mercury species in water, beverages and foods has been a special research priority in recent years because mercury, as a highly carcinogenic species, even in trace concentration, has high adverse effects on the body of living organisms. In this research, combining two extraction techniques, including microwave‐assisted cloud point extraction and dispersive‐solid phase extraction (MA‐CP‐dSPE), for the separation and pre‐concentration of mercury in environmental samples is presented. This method is based on the dispersion of nanoparticles in micellar media in the presence of a novel mono‐thiosemicarbazone Schiff base (2 N′‐[4‐diphenylamino]benzylidene) hydrazinecarbothiohydrazide) ligand. Using the experimental conditions defined in the optimization, the method allowed mercury determination from 0.020 to 350 mg/L with a detection limit of 0.005 mg/L. The accuracy of the procedure was tested by analysing certified reference material. The method was successfully applied to copper determination in spring water, beverage and rice samples.

Artemisia arborescens and Artemisia inculta from Crete; Secondary Metabolites, Trace Metals and In Vitro Antioxidant Activities.

Currently, the use of medicinal plants has increased. Artemisia species have been used in several applications, including medicinal use and uses in cosmetics, foods and beverages. Artemisia arborescens L. and Artemisia inculta are part of the Mediterranean diet in the form of aqueous infusions. Herein, we aimed to compare the secondary metabolites of the decoctions and two different extracts (methanolic and aqueous-glycerolic) of these two species, as well as their antioxidant capacity and trace metal levels. Total phenolic, total flavonoid, total terpenes, total hydroxycinnamate, total flavonol, total anthocyanin contents and antioxidant/antiradical activity were determined, and GC/MS analysis was applied to identify and quantify phenolics and terpenoids. Trace metals were quantified with ICP-MS. Aqueous-glycerolic extracts demonstrated higher levels of total secondary metabolites, greater antioxidant potential and higher terpenoid levels than decoctions and methanolic extracts. Subsequently, the aqueous-glycerolic extract of a particularly high phenolic content was further analyzed applying targeted LC-MS/MS as the most appropriate analytic tool for the determination of the phenolic profile. Overall, twenty-two metabolites were identified. The potential contribution of infusions consumption to metal intake was additionally evaluated, and did not exceed the recommended daily intake. Our results support the use of these two species in several food, cosmetic or pharmaceutical applications.

Speciation of Phosphorus in Pet Foods by Solid-State 31P-MAS-NMR Spectroscopy.

Solid-state magic angle spinning 31P NMR spectroscopy is used to identify and quantify phosphorus-containing species in pet foods. The measurement is challenging due to the long spin-lattice relaxation times (T1s). Data acquisition times are shortened by acquiring data with a tip angle smaller than 90° and shortening the repetition time. However, the spin-lattice relaxation times (T1s) of the different 31P compounds are quite different, necessitating a separate measurement for each compound in the pet food. Knowledge of T1 is used to calculate the relative amount of 31P in the samples. Samples of known concentration are also measured, enabling the quantitative measurement of total phosphorus content.