Beef Samples Research Articles

Spectroscopic assessment and quantitative analysis of the trace element composition of vegetable additives to meat products

In this scientific work, using the method of laser-induced breakdown spectroscopy (LIBS), the spectra of beef samples and impurities in meat products, namely, banana, pineapple, kiwi, bergamot, poria coconut, Chinese angelica, chicken blood vine, were measured by using developed experimental devices. The purpose of the research was to evaluate the qualitative characteristics of additives to meat semi-finished products for the potential formation of the desired properties of the products due to the analysis of the received spectrograms of trace elements of the samples when applying the LIBS method, quantitative analysis for processing the received information. The determined values of the electron temperature of the plasma, the electron density of the used raw material samples, and the assessment of the local heat balance were used as evaluation criteria. When processing the obtained data, the characteristics of the laser-induced plasma surface of the presented samples were analyzed; the electron temperature and electron density were determined, and a quantitative analysis of trace elements was carried out. LIBS technology allows rapid real-time monitoring and qualitative analysis of trace elements online and over long distances. During the research, it turned out that quantitative analysis requires further study and optimisation of experimental conditions, such as pre-treatment of samples. These conditions optimise defocusing, double laser pulse, and sample temperature, which increases the signal/noise ratio of all spectral lines. The combination of fluorescence spectroscopy and Raman technology enables higher detection sensitivity and better molecule control, creating a quantitative analysis method model that can reduce matrix effects and overcome the self-absorption effect. Among the difficulties of using LIBS technology, several elements can be noted online simultaneously, compared to Raman. The combination of spectroscopy and fluorescence spectroscopy can obtain more comprehensive information about the composition of materials, which can become a potential platform for monitoring trace elements in food products.

Phenotypic and genotypic characterization of antimicrobial resistance of non-typhoidal Salmonella from retail meat in California

Antimicrobial resistance (AMR) is a global emerging problem for food safety and public health. Retail meat is one of the vehicles that may transmit antimicrobial resistant bacteria to humans. Here we assessed the phenotypic and genotypic resistance of non-typhoidal Salmonella from retail meat collected in California in 2019 by the National Antimicrobial Resistance Monitoring System (NARMS) Retail Food Surveillance program. A total of 849 fresh meat samples were collected from randomly selected grocery stores in Northern and Southern California from January to December 2019. The overall prevalence of Salmonella was 15.31 %, with a significantly higher occurrence in Southern (28.38%) than in Northern (5.22 %) California. The prevalence of Salmonella in chicken (24.01 %) was higher (p < 0.001) compared to ground turkey (5.42 %) and pork (3.08 %) samples. No Salmonella were recovered from ground beef samples. The prevalence of Salmonella in meat with reduced antibiotic claim (20.35 %) was higher (p < 0.001) than that with conventional production (11.96 %). Salmonella isolates were classified into 25 serotypes with S. Kentucky (47.73 %), S. typhimurium (11.36 %), and S. Alachua (7.58 %) as predominant serotypes. Thirty-two out of 132 (24.24 %) Salmonella isolates were susceptible to all tested antimicrobial drugs, while 75.76 % were resistant to one or more drugs, 62.88 % to two or more drugs, and 9.85 % to three or more drugs. Antimicrobials that Salmonella exhibited high resistance to were tetracycline (82/132, 62.12 %) and streptomycin (79/132, 59.85 %). No significant difference was observed between reduced antibiotic claim and conventional production in the occurrence of single and multidrug resistance. A total of 23 resistant genes, a D87Y mutation of gyrA, and 23 plasmid replicons were identified from resistant Salmonella isolates. Genotypic and phenotypic results were well correlated with an overall sensitivity of 96.85 %. S. infantis was the most resistant serotype which also harbored the IncFIB (pN55391) plasmid replicon and gyrA (87) mutation. Data from Northern and Southern California in this study helps us to understand the AMR trends in Salmonella from retail meat sold in the highly populous and demographically diverse state of California.

In-depth exploration of the high and normal pH beef proteome: First insights emphasizing the dynamic protein changes in Longissimus thoracis muscle from pasture-finished Nellore bulls over different postmortem times

This study aimed to evaluate for the first time the temporal dynamic changes in early postmortem proteome of normal and high ultimate pH (pHu) beef samples from the same cattle using a shotgun proteomics approach. Ten selected carcasses classified as normal (pHu < 5.8; n = 5) or high (pHu ≥ 6.2; n = 5) pHu beef from pasture-finished Nellore (Bos taurus indicus) bulls were sampled from Longissimus thoracis muscle at 30 min, 9 h and 44 h postmortem for proteome comparison. The temporal proteomics profiling quantified 863 proteins, from which 251 were differentially abundant (DAPs) between high and normal pHu at 30 min (n = 33), 9 h (n = 181) and 44 h (n = 37). Among the myriad interconnected pathways regulating pH decline during postmortem metabolism, this study revealed the pivotal role of energy metabolism, cellular response to stress, oxidoreductase activity and muscle system process pathways throughout the early postmortem. Twenty-three proteins overlap among postmortem times and may be suggested as candidate biomarkers to the dark-cutting condition development. The study further evidenced for the first time the central role of ribosomal proteins and histones in the first minutes after animal bleeding. Moreover, this study revealed the disparity in the mechanisms underpinning the development of dark-cutting beef condition among postmortem times, emphasizing multiple dynamic changes in the muscle proteome. Therefore, this study revealed important insights regarding the temporal dynamic changes that occur in early postmortem of high and normal muscle pHu beef, proposing specific pathways to determine the biological mechanisms behind dark-cutting determination.

Development of a cabin for fast freezing in a household refrigerator and examination of its effects on the quality characteristics of beef

In this study, a cabin design was made for fast freezing in household refrigerators using different fan types (radial fan velocity of 1100, 1500 and 1900 rpm) and axial (1350 rpm) and the effects on the quality characteristics of beef were examined. Before the freezing process, the beef (Semitendinosus) was sized at 10 × 10 × 2 cm as a single fillet; 2 × 2 × 2 cm as the cubed sample and the minced beef was prepared by the butcher from the same meat and shaped with the dimensions of 10 × 10 × 2 cm. It was seen that when the fan velocity was 1900 rpm during the freezing process, the weight (0.39–11.61 %) and cooking loss (26.69–44.66 %) values of the beef samples decreased. A decrease was observed in the TBARS values (0.34–0.87) of the sample as the radial fan velocity increased in radial fan. When the total color change values (3.96–7.59) of all beef samples were examined, it was seen that the least color change was achieved with the axial fan before and after cooking. When the textural properties of the meat were examined before and after cooking, it was observed that the hardness decreased as the radial fan velocity increased, and the lowest hardness value was obtained from freezing with the axial fan. In addition, porosity values decreased and protein denaturation temperatures increased due to the formation of smaller ice crystals with the axial fan. As a result, it has been observed that fan type and velocity have significant effects on accelerating the freezing process and preserving the quality of beef samples.

Innovate plant-based burger patties using defatted sesame cake flour, chickpea flour, coffee silver skin and pomegranate juice as natural colorant: effects on nutritional and acceptability aspect

PurposeThis study aims to evaluate the nutrient content and acceptable qualities of plant-based burger patties (PBBP) formulated with chickpea flour, defatted sesame cake (DSC) flour, coffee silver skin and pomegranate juice as colorant.Design/methodology/approachThe chemical composition, energy value, cholesterol content, amino acid composition, cooking loss, pH, color characteristics and sensory attributes of PBBP were analyzed using official procedures and compared to beef burger. FindingsPBBP had a protein value of 16.0 g/100g, which is nearly close to the protein content of the beef burger (18.1 g/100g). The fat content of the PBBP was approximately three times lower than that of the beef burger. The fiber content in PBBP was approximately 23 times as high as that in beef burgers samples (p = 0.05). The raw PBBP samples supplies 178 Kcal/100g, whereas beef burger possessed 259 Kcal/100g. Neither the raw nor the cooked PBBP samples contained any cholesterol. Both the beef and PBBP displayed acceptability scores higher than 7.0, which suggests that PBBP was well accepted.Originality/valueIt is concluded that the PBBP sample exhibited a protein value of 16.0 g/100g, which is comparable to the protein level of beef burgers (18.1 g/100g). The fat level of the PBBP samples was significantly lower than that of the beef burger samples. Uncooked PBBP samples contained significantly higher fiber content compared to beef burger samples. No cholesterol was found in raw or cooked PBBP samples. Overall acceptance scores for both beef and PBBP samples exceeded 7.0, suggesting that the proposed product (PBBP) was received favorably.

Novel soy protein isolate films incorporated with phage CAM-21 show strong antimicrobial effects against E. coli O157:H7

Due to their specificity, bacteriophages are becoming more widely used as antibacterial agents in the food industry. However, their effectiveness in food is often compromised by food components that can lead to a loss of their biological activity. In this study, soy protein isolate (SPI)-based packaging films incorporated with Escherichia phage CAM-21 were developed using a solution casting method. CAM-21 was relatively stable at pH 3–11 and temperatures up to 55 °C after 1 h of incubation. It remained active on the surface of raw beef, ground beef, and baby spinach after 36 h at 4 °C. The distribution of CAM-21 in the films was uniform, and its incorporation did not affect the film microstructure. No significant impact on the color, water vapor permeability, opacity, and mechanical properties of the films was observed. The antimicrobial activity of CAM-21-incorporated films was significantly enhanced in beef products inoculated with E. coli O157:H7. CAM-21-containing films significantly decreased the number of bacteria on raw beef samples by up to 1.5 and 2.0 log CFU/g after 3 and 5 days of refrigerated storage, respectively. These findings suggest that SPI films containing Escherichia phage CAM-21 have potential as antimicrobial packaging materials for preserving meat products.

Evaluation of the effect of active essential oil components added to pickled-based marinade on beef stored under vacuum packaging: Insight into physicochemical and microbiological quality

This research aimed to evaluate the effects of the addition of active essential oil components (linalool and/or eugenol) to a pickle-based marinade on controlling spoilage and extending the shelf life of fresh beef stored under vacuum packaging at 4 °C. Linalool and eugenol were used either separately at a concentration of 0.2 % (w/w) or together (1:1 ratio) to preserve marinated beef under vacuum packaging for 15 days. Samples were assessed for pH, color, texture, oxidative degradation, and microbiological parameters. All marinades exhibited significantly lower TBARS values than the control sample. The addition of linalool or eugenol to the marinate showed a significant antibacterial effect on total aerobic mesophilic bacteria (TAMB), lactic acid bacteria (LAB), Pseudomonas spp., and total coliform, and the reductions in microbial counts are as follows: TAMB: 1.563 log CFU/g and 1.46 log CFU/g; Pseudomonas spp.: 1.303 log CFU/g and 1.08 log CFU/g; LAB: 0.323 log CFU/g and 0.357 log CFU/g. Marinated beef with linalool and/or eugenol was found to be effective against the growth of yeast and mold. The use of eugenol presented the most effective inhibition activity against yeast and mold by reducing the number of yeast and molds to an uncountable level on the 12th and 15th days of storage. Physicochemical analysis also showed that the addition of active essential oils to marinade did not cause any undesirable effects on the color and texture properties of beef samples. Therefore, the findings revealed that eugenol and linalool could be suitable alternatives for beef marination.

Susceptibility to antibiotics and virulence profiling of Proteus mirabilis among foodstuff

Proteus mirabilis is a genus of bacteria that can cause foodborne diseases. We collected 100 canned food samples from local supermarkets in Hillah (Iraq), including juice (23%), milk products (22%), beef (20%), fish (14%), milk (12%), and tomato paste (9%) samples. We subsequently characterized some virulence factors of P. mirabilis found in these foodstuff, including biofilm formation, protease activity, motility, haemolysis, adhesion, urease production, lipase pro¬duction, and antibiotic susceptibility. In a total of 32 foodstuff samples of positive culture, P. mirabilis was isolated in 15 (46.8%), including 3 juice samples, 4 milk product samples, 2 beef samples, 1 fish sample, 3 milk samples, and 2 tomato paste samples. All isolates exhibited swarming motility (100%) and urease production (100%), while none of the isolates was found to produce haemolysin. The results of the antibiotic susceptibility test revealed a higher re¬sistance against ampicillin (86.6%).

Detection and quantification of 4-oxo-2-nonenal in plant-based meat and beef

Oxidative degradation of lipids and proteins in food causes loss of nutrition, produces genotoxic oxidative byproducts, and increases health concerns. 4-Oxo-2-nonenal (4-ONE) is a highly reactive and toxic aldehyde, recently identified as a novel lipid peroxidation byproduct. However, naturally formed 4-ONE and its interaction with proteins in food are still not fully understood. In this study, methods for the detection and quantification of 4-ONE were further developed and used. The developed method successfully detected the formed lipid oxidation products (LOPs) and protein oxidation products (POPs) during cooking, as well as after in-vitro digestion of plant-based (PB) meat and beef. The method used exhibited consistencies of detection of 4-ONE in raw, cooked, and in-vitro digested PB meat and beef samples. Furthermore, the findings of this study show that PB meat had significantly higher levels of POPs but lower levels of aldehydes (4-ONE and malondialdehyde) than beef samples. The results revealed the LC–MS/MS method for detecting and quantifying 4-ONE as a novel lipid oxidation marker was promising. Furthermore, the results indicated that the protein in PB meat may be prone to covalent modification of aldehyde and free radical attacks, thus reducing its proteolysis during digestion. Future studies should further assess the covalent binding ability of aldehydes (especially 4-ONE) in different types of protein, as well as the interaction between lipid and protein oxidation. Processors should develop new strategies to avoid undesirable LOPs and POPs in PB meat and beef, to improve their nutrition and relieve long-term health concerns.

Seroprevalence and molecular detection of Toxoplasma gondii and Neospora caninum in beef cattle and goats in Hunan province, China

BackgroundToxoplasma gondii and Neospora caninum are closely related protozoan parasites that are considered important causes of abortion in livestock, causing huge economic losses. Hunan Province ranks 12th in the production of beef and mutton in China. However, limited data are available on the seroprevalence, risk factors and molecular characterization of T. gondii and N. caninum in beef cattle and goats in Hunan province, China.MethodsSera of 985 beef cattle and 1147 goats were examined for the presence of specific antibodies against T. gondii using indirect hemagglutination test (IHAT) and anti-N. caninum IgG using competitive-inhibition enzyme-linked immunoassay assay (cELISA). Statistical analysis of possible risk factors was performed using PASW Statistics. Muscle samples of 160 beef cattle and 160 goats were examined for the presence of T. gondii DNA (B1 gene) and N. caninum DNA (Nc-5 gene) by nested PCR. The B1 gene-positive samples were genotyped at 10 genetic markers using the multilocus nested PCR-RFLP (Mn-PCR-RFLP).ResultsSpecific IgG against T. gondii were detected in 8.3% (82/985) and 13.3% (153/1147) and against N. caninum in 2.1% (21/985) and 2.0% (23/1147) of the beef cattle and goats, respectively. Based on statistical analysis, the presence of cats, semi-intensive management mode and gender were identified as significant risk factors for T. gondii infection in beef cattle. Age was a significant risk factor for T. gondii infection in goats (P < 0.05), and age > 3 years was a significant risk factor for N. caninum infection in beef cattle (P < 0.05). PCR positivity for T. gondii was observed in three beef samples (1.9%; 3/160) and seven chevon samples (4.4%; 7/160). Genotyping of PCR positive samples identified one to be ToxoDB#10. The N. caninum DNA was observed in one beef sample (0.6%; 1/160) but was negative in all chevon samples.ConclusionsTo our knowledge, this is the first large-scale serological and molecular investigation of T. gondii and N. caninum and assessment of related risk factors in beef cattle and goats in Hunan Province, China. The findings provide baseline data for executing prevention and control of these two important parasites in beef cattle and goats in China.Graphical

Real-time PCR method based on single-copy nuclear DNA sequences for the quantitative detection of pork adulteration in processed beef products

Meat adulteration, which adversely impacts food safety, economy, and religious beliefs, has come to be considered as a matter of global concern. The lack of a standard method that can be employed to quantitatively detect the pork content in processed meat products has led to demands for an accurate and sensitive method capable of detecting the proportion of pork in processed beef products. In this study, we aimed to develop a real-time PCR-based method to accurately and quantitatively detect pork adulteration in processed beef. We used bovine and porcine species-specific sequences to design primers and probes that specifically amplified bovine and porcine genes. Our real-time PCR method was evaluated via quantitative detection of reference samples and found to be highly accurate. Sensitivity analyses indicated that the limit of detection for beef as well as for pork was as low as five copies, while the limit of quantification for beef and for pork was 0.1%. To compare qualitative and quantitative results, beef samples cross-contaminated with pork were analyzed using both quantitative and standard qualitative methods. No undeclared meat components were found among the 25 processed meat products that were analyzed to evaluate the applicability of the quantitative method. However, the beef content in some processed beef products was very low, even approaching zero. This real-time PCR method may be reliably applied for quantitatively detect pork adulteration in processed beef products. Thus, this method of ours may help promote healthy and sustainable development of meat products.

In vitro digestion of beef and vegan burgers cooked by microwave technology: Effects on protein and lipid fractions

Commercial beef burgers and vegan analogues were purchased and, after a microwave treatment, they were submitted to an in vitro digestion (INFOGEST). Vegan cooked burgers showed similar protein content (16–17 %) but lower amounts of total peptides than beef burgers. The protein digestibility was higher in beef burgers. Peptide amounts increased during in vitro digestion, reaching similar amounts in both types of products in the micellar phase (bioaccessible fraction). The fat content in cooked vegan burgers was significantly lower than in beef burgers (16.7 and 21.2 %, respectively), with a higher amount of PUFAs and being the lipolysis activity, measure by FFA, less intense both after cooking and after the gastrointestinal process. Both types of cooked samples showed high carbonyl amounts (34.18 and 25.51 nmol/mg protein in beef and vegan samples, respectively), that decreased during in vitro digestion. On the contrary, lipid oxidation increased during gastrointestinal digestion, particularly in vegan samples. The antioxidant capacity (ABTS and DPPH) showed higher values for vegan products in cooked samples, but significantly decreased during digestion, reaching similar values for both types of products.

Specific and Simultaneous Detection of E. coli O157:H7 and Shiga-like Toxins Using a Label-Free Photonic Immunosensor

The current study outlines the advancement of an innovative technique for the simultaneous detection of E. coli O157:H7 and its Shiga-like toxins in food samples by utilizing a photonic label-free biosensor coupled with a microfluidic system. This detection method relies on ring resonator transduction that is functionalized with specific bioreceptors against O157:H7 on silicon nitride surfaces capable of binding specifically to the antigen bacterium and its verotoxins. This experiment included the characterization of selected monoclonal and polyclonal antibodies employed as detection probes through ELISA immunoassays exposed to target bacterial antigens. A thorough validation of photonic immunosensor detection was conducted on inoculated minced beef samples using reference standards for E. coli O157:H7 and its verotoxins (VTx1 and VTx2) and compared to gold-standard quantification. The lowest limit-of-detection values of 10 CFU/mL and 1 ppm were achieved for the detection of bacteria and its verotoxins. In this study, the lowest limit of quantification (LoQ) achieved for bacterial quantification was 100 CFU/mL, and, for verotoxins, it was 2 ppm. This study confirmed the effectiveness of a new quality control and food hygiene method, demonstrating the rapid and sensitive detection of E. coli O157:H7 and its verotoxins. This innovative approach has the potential to be applied in food production environments.

Nanoparticles-based lateral flow strip for halofuginone ultrasensitive detection in chicken and beef

Halofuginone (HFG) is a widely used anti-coccidiosis drug in animal husbandry. There is an urgent need for a rapid detection method to detect HFG residues in chicken and beef to ensure human health. In this study, suitable HFG haptens were selected using computer simulation, and a highly sensitive monoclonal antibody (mAb) was developed with the 50%-inhibitory concentration (IC50) of 0.66 ng/mL. Then, gold nanoparticle-based lateral flow immunochromatographic (ICA) strips for HFG detection were produced. Under optimization conditions, the ICA strips exhibited outstanding performance with a visual limit of detection (vLOD) of 50 μg/kg and 5 μg/kg, and cut-off values of 100 μg/kg and 10 μg/kg, for chicken and beef samples, respectively. In addition, the reliability of strips was verified by enzyme linked immunosorbent assay (ELISA) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Therefore, the developed strip can be used as an effective tool for HFG residues screening in chicken and beef samples.

Rapid detection of chlortetracycline and metacycline in food based on the fluorescence quenching effect of ZnS@CdS quantum dots

Excessive accumulation of tetracycline can not only cause harm to the environment, but also threaten human health through the food chain. In order to reduce the likelihood of people being harmed by these drugs, new methods for the detection of chlortetracycline (CTC) and metacycline (MTC) based on the ZnS@CdS quantum dot (QDs) fluorescence quenching reaction were established. High quality CdS QDs capped by mercaptopropionic acid and ZnS were prepared, which were characterized by transmission electron microscopy, fluorescence, ultraviolet visible spectra, fourier transform infrared, X-ray diffraction and thermogravimetric analysis. The study showed that there was an interaction between CTC/MTC and ZnS@CdS QDs, and the electrostatic force was the main force. The Stern-Volmer analysis showed that the quenching was static, which was further proved by fluorescence lifetime experiment. Under the optimized experimental conditions, linear calibration curves for detecting CTC/MTC were obtained with a limit of detection of 12.91/12.10 ng mL−1. The contents of CTC/MTC in milk, tangerine, beef and pork samples were detected. The recoveries of CTC/MTC were satisfactory. The established method had good analytical performance and can be used for the detection of more actual samples.

Potential Pharmaceutical Biotechnology Products in the Form of Formulations and Preparations of Telang Flower Kombucha Dish Soap (Clitoria ternatea L) as an Antibacterial from Beef (Bos taurus) Isolate

This research aims to see the potential of each formulation and preparation of dishwashing soap with the active ingredient telang flower kombucha in inhibiting the growth of pathogenic bacteria isolated from beef. This research is a laboratory experiment, namely by making a dishwashing soap base without the active substance of telang flower kombucha. Make a dishwashing soap base that adds the active substance of butterfly pea flower kombucha at concentrations of 20%, 30% and 40%. Biochemical identification results have shown that beef samples contain gram-positive bacteria in the form of Staphylococcus aureus and Listeria monocytogenes, as well as gram-negative bacteria in the form of Salmonella thyposa and Escherichia coli. The results of this research have also proven that pharmaceutical biotechnology products in the form of formulations and dishwashing soap preparations with the active ingredient telang flower kombucha have a positive correlation in inhibiting the growth of the four test bacteria. Based on the one-way ANOVA statistical test at each P value &lt;0.05, it proves that telang flower kombucha dish soap at a concentration of 40% according to post hoc analysis is not significantly different from concentrations of 20% and 30% as a pharmaceutical and antibacterial biotechnology product. isolated from beef. The conclusion of this research is that the formulation and preparation of dishwashing soap at a concentration of 40% proved to be the most effective as a pharmaceutical biotechnology product in inhibiting the growth of the four test bacteria.

Food safety knowledge and practices among raw meat handlers and the microbial content of raw meat sold at Kumasi Abattoir Butchery Shops in Kumasi, Ghana

BackgroundFoodborne diseases affect nearly 600 million people each year, that is, one in every ten people, and their outbreaks are most common in low- and middle-income countries, particularly in Africa. This study investigated the food safety practices among raw meat handlers and the microbial quality of the meat from the butchery shops in Kumasi Abattoir, Ghana.MethodsThis study employed a descriptive cross-sectional study and collected quantitative data on factors associated with food safety and hygienic practices among raw meat handlers and the microbial quality of the raw meat using a structured questionnaire and standard laboratory methods, respectively. The study used all 50 beef vending shops in the butchery for questionnaire aspect and fresh beef samples were obtained from 10 vendors in the butchery shop. Appropriate methods were followed to analyse questionnaire data and meat samples.ResultsMost of the butchers (72%) were between the ages of 31 and 45, and they were predominantly Muslims (68%). Most of the respondents (48%) had basic education. All the respondents had food safety certificates from the local authority but needed adequate knowledge of meat safety. Most respondents (90%) handled meat and money with the same bare hands, thus contaminating the meat. The study showed that the maximum Total Viable Count (TVC), Total Staphylococcus Count (TSC), and Total Escherichia coli Count (TEC) were 5.60, 4.39 and 5.13 cfu/g, respectively. The study also revealed that all the meat samples were Salmonella species-free.ConclusionsMicroorganisms in raw beef indicate a public health hazard. It gives a signal of a possible occurrence of food-borne intoxication and infection if not controlled. Environmental health officers in the Greater Kumasi area should organize food safety training and educate raw meat handlers on the importance of food safety and its consequences.

An Innovative and Efficient Fluorescent Detection Technique for Salmonella in Animal-Derived Foods Using the CRISPR/Cas12a-HCR System Combined with PCR/RAA.

Here, we present a method for Salmonella detection using clustered regularly interspaced short palindromic repeats associated with the CRISPR-associated protein 12a-hybridization chain reaction (CRISPR/Cas12a-HCR) system combined with polymerase chain reaction/recombinase-assisted amplification (PCR/RAA) technology. The approach relies on the Salmonella invA gene as a biorecognition element and its amplification through PCR and RAA. In the presence of the target gene, Cas12a, guided by crRNA, recognizes and cleaves the amplification product, initiating the HCR. Fluorescently labeled single-stranded DNA (ssDNA) H1 and H2 were introduced, and the Salmonella concentration was determined based on the fluorescence intensity from the triggered HCR. Both assays demonstrate high specificity, sensitivity, simplicity, and rapidity. The detection range was 2 × 101-2 × 109 CFU/mL, with an LOD of 20 CFU/mL, and the entire process enabled specific and rapid Salmonella detection within 85-105 min. Field-incurred spiked recovery tests were conducted in mutton and beef samples using both assays, demonstrating satisfactory recovery and accuracy in animal-derived foods. By combining CRISPR/Cas12a with hybridization chain reaction technology, this study presents a rapid and sensitive Salmonella detection method that is crucial for identifying pathogenic bacteria and monitoring food safety.

The analysis of lamb and beef fatty acids with a 30 m BPX70 column is comparable with a 120 m column

Gas chromatography (GC) analysis of fatty acid methyl esters (FAME) typically uses long capillary columns (≥ 100 m) which can be expensive and time consuming. The current study determined whether the major FAME of interest for human health in lamb and beef can be quantified using a 30 m compared with 120 m moderately polar capillary (BPX70) column. Lamb and beef samples with a range of intramuscular fat content from either grass- or grain-fed animals were analysed. All major FAME of human health importance, including omega-3 and omega-6 polyunsaturated fatty acids and conjugated linoleic acid (CLA) isomers, could be identified on the 30 m BPX70 column. The correlation (r2) for fatty acid percentage between columns was > 0.98 for all major n–3PUFA and > 0.86 for all major CLAs. When animals were fed a grain-based diet, C18:1n–7t (vaccenic acid) could not be resolved from C18:1n-8t when analysed on the 30 m column. The FAME profile of lamb and beef, particularly those important for nutritional composition tables, can be determined using a 30 m BPX70 column, thereby saving time and expense compared with longer columns. Particular care should be employed when analysing samples from grain-fed animals due to co-eluting of C18:1n–8t.

Parallel biosensor platform for the detection of carbapenemase-producing E. coli in spiked food and water samples

The rise of carbapenem-resistant E. coli, specifically carbapenemase-producing (CP) strains, in biological samples needs attention. Early detection is crucial in minimizing and controlling their detrimental impact. However, their rapid identification directly from contaminated samples has not been documented well. This study presented an affordable and rapid platform for extraction and detection of CP E. coli, particularly Klebsiella pneumoniae carbapenemase (KPC)-producing E. coli from spiked food and water samples. Glycan-coated magnetic nanoparticles (gMNPs) were utilized to extract the bacteria from contaminated buffer solution, tap water, romaine lettuce, ground beef, and chicken breast samples. The bacterial cell concentration by gMNPs was achieved in the presence of food microparticles and natural microflora. Transmission Electron Microscopy (TEM) illustrated the successful isolation of bacteria and their interaction with gMNPs. For detection, a parallel plasmonic biosensor using dextrin-coated gold nanoparticles (dGNPs) was developed. The biosensor successfully detected KPC-producing E. coli from pure culture by targeting uidA and blaKPC genes and did not require any PCR amplification. The stability of dGNPs, shown by their red appearance, indicated the presence of target DNA. In contrast, their agglomeration, given by their blue or purple color, indicated the absence of target DNA. This stability and agglomeration of the dGNPs were confirmed by TEM and quantified by absorbance spectrum measurements. Further, the designed biosensor platform successfully identified the DNA extracted from water and food samples contaminated with KPC-producing E. coli, with no false positives for the samples contaminated with non-target bacteria. The biosensor successfully detected the target organism, where the original concentration prior to magnetic extraction was 103 CFU/mL. The biosensor results were further confirmed with the standard PCR assay. As a proof-of-concept, these findings indicate promising applications of the integrated platform for cost-effective and rapid bacterial detection from complex matrices within <7 h. The gained insights may facilitate future application of this platform for its complete validation study to improve real-world applicability.