Determination of antibiotic residues in milk and assessment of human health risk in Bangladesh

High prevalence of low-concentration antimicrobial residues in commercial fish: A public health concern in Bangladesh

Antibiotics are widely used in commercial fish farms in Bangladesh for therapeutic and prophylactic purpose, raising concerns about antimicrobial resistance (AMR) and environmental contamination. This study used Thin Layer Chromatography to detect antimicrobial residues in four commercially available fish species- Tilapia (Oreochromis aureus), Stinging catfish (Heteropneustes fossilis), Climbing perch (Anabas testudineus), and Pabda (Ompok pabda)-with 100 samples per species. Ultra High-Performance Liquid Chromatography quantified residues in a subset of 25 samples per species. The prevalence of Ciprofloxacin, Oxytetracycline, and Chlortetracycline residues varied significantly among fish species, with the highest prevalence observed for Ciprofloxacin in Tilapia (42%), Oxytetracycline in Pabda (41%), and Chlortetracycline in Tilapia (49%). Additionally, the prevalence of Levofloxacin and Chlortetracycline differed by sampling location, with the highest levels found in Jhawtala market, 27.5% for Levofloxacin and 53.8% for Chlortetracycline. Furthermore, residue concentrations were highest for Enrofloxacin in Climbing perch (69.32 µg/Kg) and Oxytetracycline in Pabda (88.73 µg/Kg). The highest Hazard Quotient (HQ) was for Enrofloxacin in Climbing perch (0.480), followed by Pabda (0.460), Stinging catfish (0.420), and Tilapia (0.387). While the HQ values were below 1.0, indicating no immediate toxicological risk, residues raise public health concerns due to the chance of potential AMR development. Further research is needed on antimicrobial bioaccumulation, indirect exposure sources, environmental contamination, and antimicrobial resistance in aquaculture and wild fish.

Chemically reduced graphene oxide based assembly of Aptasensor for sensitive and probe-free detection of penicillin-G

The widespread use of antibiotics in livestock and poultry leads to antibiotic residues in food, posing public health risks. To ensure food safety, monitoring antibiotic levels in dairy and poultry is essential, especially for Penicillin-G (Pen-G), a frequently used β-lactam antibiotic. This study presents an electrochemical aptasensor for detecting Pen-G in food samples, using chemically reduced graphene oxide (crGO) conjugated with Pen-G-specific aptamer on electrode. The sensors construction was validated via various microscopy and spectroscopy techniques and its performance optimized by adjusting factors such as pH, scan rate, temperature, concentration of aptamer, and reaction time using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). It achieved a detection limit of 1.24 pM, effectively distinguishing Pen-G from other antibiotics in real milk, meat, and egg samples, with stability for up to 3 weeks, making it a valuable tool for antibiotic monitoring in food products.

Study of biological safety of camel milk after treatment with different antibiotics

The use of antibiotics in camels is generally based on the doses applied to cattle, despite the known differences in plasma pharmacokinetics between camel and cattle. The demand for camel milk increased due to the belief that traditional camel farming practices produce safe milk with health benefits. For assessing the importance of antibiotic residues in camel milk and to propose a convenient withdrawal period, a trial was conducted on 10 lactating camels (7-12 years old; 450 kg life weight (LW), 7-8 liter of milk production per day) at mid-lactation receiving an injection of 40 mL of Pen-strep® (benzylpenicillin-procaine 200,000 IU/1 ml and dihydrostreptomycin sulfate 200 mg/1 ml) and Nitox® (oxytetracycline dihydrate 200 mg/1 ml). The antibiotic residues were measured in the milk 30 min after injection then on day 1, 2, 3, 7, 9, 14, 19, 24 and 56 by using HPLC-MS/MS. Results showed that penicillin's mean residual concentration (0.3 ± 0.013 mg/kg) remained 7.5 times above the maximum residue limit (MRL) even on 56th day. In contrast, streptomycin fell below the MRL within 30 minutes and averaged 1 µg/kg by day 56. Oxytetracycline levels exceeded the MRL (0.1 mg/kg) until day 14 but dropped to a safe level of 0.018 ± 0.01 mg/kg by day 24. In conclusion, the decline in streptomycin concentration post-injection appeared rapid and efficient, the elimination of penicillin and tetracycline was slow. These preliminary results lead to considering the necessity to adapt the waiting time to the dairy camel.

Unveiling antibiotic residue contamination: assessing yak, dzomo, and hill cattle milk from himalayan region through QuEChERS-HPLC approach and health risk assessment

Milk obtained from Yaks, yak hybrid (Dzomo) and hill cattle (Gauri) is major source of nutrients for people inhabiting Himalayas. In present study, QuEChERS approach together with HPLC-UV was used for detection and quantification of tetracycline residues in 170 raw milk samples of hill cattle (60), dzomo (58) and yaks (52) collected from high altitude regions of Himachal Pradesh, a Western Himalayan state of India. The method validated as per European Commission's guidelines was found to be linear (R2 > 0.99), accurate (recoveries: 80%~90%) precise (RSD ~ 10%) with LOD of 0.55 and 1.37 ng/mL for tetracycline and oxytetracycline, respectively. Antibiotics were detected in 8 samples, with only 3 samples exceeding MRLs. Hazard Index values for exposure to detected antibiotic residues in milk were below 1 suggesting that the population is likely protected from acute health risks associated with such exposure. However, for children, % contribution to acceptable daily intakes of antibiotics only through milk was found to be high indicating probable risks. Therefore, ongoing monitoring and adherence to regulatory standards are important to ensure the safety of milk and other food products. There is also a need to educate farmers and improve their perception about antibiotics and their usage to safeguard consumer's health.

Spleen proteome profile reveals immune responses induced by dietary spray-dried plasma against Salmonella Enteritidis infection in broiler chicks

Salmonella infection severely impacts poultry health, productivity, and food safety. Spray dried plasma (SDP) shows good efficacy as an alternative to in-feed antibiotics for broiler chickens. Our objective was to identify potential mechanisms of SDP benefits by analyzing effects on spleen proteome and in response to Salmonella Enteritidis challenge (SE). A 2 × 2 factor study of broilers (n = 240) were assigned to CON (control) or SDP (30g/kg) diet at 1 day of age, and gavaged with sterile tryptic soy or 7.46 × 108 CFU SE /mL, resulting in 4 groups CON (n = 60), SDP (n = 60), CON-SE (n = 60) and SDP-SE (n = 60). On d 2 and d 5 post-challenge, chicks (n = 4/treatment) were euthanized, and spleen collected to isolate proteins, and measure using label-free liquid chromatography tandem mass spectrometry. Data were mapped to Gallus gallus Uniprot database, and differentially abundant proteins (DAP; P < 0.05) identified using ANOVA. Across all samples, 4,300 proteins were identified, and SDP treatment resulted 116 DAP. Proteins (56) that decreased were associated with positive regulation of I-kappaß kinase/NF- kappaß signaling and positive regulation of apoptosis process. Proteins that increased (60) were associated with integral components of endoplasmic reticulum membrane and necroptosis pathway. Analysis of the interaction between SDP and SE challenge found 119 DAP. The proteins that increased (87) were associated with RNA binding, ATP binding, mRNA splicing, and protein phosphorylation. Proteomic signatures of spleen reveals that the actions of SDP in broiler chicks are anti-inflammatory and anti-apoptotic and predicted to inhibit pro-inflammatory response through the inhibition of NF-ĸB. However, in the presence of Salmonella infection, it promotes regulated inflammatory response.

Management factors affecting milk yield, composition, and quality on smallholder dairy farms

A cross-sectional study on 156 smallholder dairy farms in Rwanda was carried out to assess the association between farm management practices and milk yield and quality. A pre-tested questionnaire was used to collect data on cow characteristics and farm management practices. Milk yield was recorded at household level, milk composition was monitored using a Lactoscan device (Milk Analyzer). Somatic cell count (SCC) was determined using a DeLaval cell counter (DCC). A Delvotest SP-NT kit was used to determine antibiotic residues in raw milk. Most dairy cows were kept in zero-grazing system (84.6%) and most farmers had less experience of dairy production (78.2%). Mean daily milk yield was 3.9 L/cow and was associated with type of breed, milking frequency, stage of lactation, and parity. Mean milk content of protein, fat, lactose and solid non-fat, and density were normal and showed no association with different management practices. Based on SCC analyses, 65.8% of the milk samples with less than 300,000 cells/mL were graded as acceptable for delivery to a milk collection centre (MCC) and 12.9% of the samples tested positive for antibiotic residues. These findings suggest low milk yields on smallholder farms in Rwanda that are attributable to type of breed and prevalent high level mastitis, among other factors. The results also indicate possible non-compliance with withdrawal periods, resulting in antibiotic residues in milk, which has public health implications for consumers. Routine testing at MCC for both SCC and antibiotic residues is important for quality control.

Residual antibiotics in milk samples: Assessing the risk and prevalence in Bangladesh

The study aimed to analyze five commonly used veterinary antibiotics: tetracycline (TC), oxytetracycline (OTC), doxycycline (DOX), chlortetracycline (CTC), and enrofloxacin (ENR) in different types of milk samples, risk estimation, and to investigate the correlation between the presence of multiple antibiotic residues. About 27 milk samples, such as raw milk from collection centers, processed milk from processing plants, pasteurized, UHT, and flavored milk from retail stores, were examined using RP-HPLC against five veterinary antibiotics in Dhaka, Bangladesh. The correlation between antibiotics was analyzed using Pearson's correlation test. OTC was prevalent in 100 % of the analyzed samples, while CTC, ENR, TC, and DOX were found in 29.63 %, 22.22 %, 18.52 %, and 7.41 % of the samples, respectively. Only OTC residues were detected in both raw and soon-after-processed milk. However, most of the UHT and flavored milk samples showed the occurrence of multiple antibiotic residues. Among the detected samples, 37.04 % exceeded the MRLs, while 44.44 % were near the limit. The mean concentration of TC was higher than others. The correlation test revealed a significant moderate to strong positive correlation between TC, CTC, DOX, and ENR, while OTC showed no significant correlation with the other antibiotics. Risk analysis showed no immediate risk from detected antibiotics but can raise concern due to continuous exposure. The results obtained from this study underscore the importance of adhering to appropriate withdrawal periods and implementing appropriate quality control protocols to ensure the protection of public health.

Antibiotic Residues in Animal Products from Some African Countries and Their Possible Impact on Human Health

This review investigates the levels of antibiotic residues in animal products, types of antibiotics, and their possible impact on human health in Africa. The literature search involved the use of a systematic survey using data that were published from Africa from 2015 to 2024. The search terms used the Boolean operators with keywords such as antibiotics, antibiotic residues, antibiotics in animal products in Africa, and impact on human health. Only research conducted in Africa was used in the present study. The findings showed that the most prevalent groups of antibiotic residues were aminoglycoside, macrolides, β-lactams, fluoroquinolones, tetracyclines sulfonamides, and phenicols. Tetracycline showed the most prevalent antibiotic residue with 43% mostly from East Africa, followed by sulfonamides at 19%, and β-lactams at 16%; most of the antibiotic residue levels were higher than the World Health Organization permissible limit. Noncompliance with withdrawal periods and maximum residue limits for antibiotics used in food-producing animals may lead to negative outcomes such as allergic reactions, teratogenicity, carcinogenicity, microbiome alterations, and, most notably, antibiotic resistance. As a result, there is a need for constant monitoring of antibiotic residues in animal products in addition to the consideration of alternatives to antibiotics in order to avoid their health implications.

Monitoring Antibiotic Pollutants in Water Using Electrochemical Techniques: A Detailed Review

This review article examines the application of electrochemical methods for detecting four prevalent antibiotics - azithromycin (AZM), amoxicillin (AMX), tetracycline (TC), and ciprofloxacin (CIP) - in environmental monitoring. Although, antibiotics are essential to contemporary treatment, their widespread usage has contaminated the environment and given rise to antibiotic resistance. Electrochemical techniques offer sensitive, rapid, and cost-effective solutions for monitoring these antibiotics, addressing the limitations of traditional methods. The review provides a comprehensive analysis of various electrochemical approaches, including voltammetry, amperometry, photoelectrochemical and so on, highlighting their principles, advantages, and limitations. Key findings underscore the effectiveness of these methods in detecting antibiotics at trace levels in complex environmental matrices. Implications for environmental health and policy are discussed, emphasizing the importance of reliable detection techniques in mitigating antibiotic resistance and safeguarding ecosystems. Lastly, the article outlines future research directions aimed at enhancing the sensitivity, selectivity, and field-applicability of electrochemical sensors, thus advancing their utility in environmental monitoring and public health protection.

Residues of Tetracycline, Erythromycin, and Sulfonamides in Beef, Eggs, and Honey from Grocery Stores in Knoxville, Tennessee, USA: Failure of Cooking to Decrease Drug Concentrations

This study evaluated the concentrations of tetracycline, erythromycin, and sulfonamide in beef, eggs, and honey products sold at grocery stores and whether standard cooking to 160 °F (71 °C) reduced the concentrations of antimicrobials spiked into the evaluated food products. In June 2021, the concentrations of selected antimicrobials in 65 samples (8 beef, 48 eggs, 9 honey samples) purchased from grocery stores within Knoxville, Tennessee, were measured using enzyme-linked immunosorbent assays. The Kruskal-Wallis test was used to assess the differences in the median tetracycline concentrations across food types, while the Mann-Whitney test was used to compare the erythromycin residue concentrations between beef and honey. Linear regression was used to analyze whether standard cooking at 160 °F (71 °C) reduced antimicrobial concentrations. Detectable tetracycline concentrations were found in all beef (8/8, 100%), eggs (46/48, 96%), and honey (9/9, 100%) samples, with median concentrations of 7.73, 5.62, and 13.13 µg/kg, respectively. Honey had significantly higher tetracycline concentrations than eggs (p = 0.002). Detectable erythromycin concentrations were found in beef (5/8, 63%) and honey (9/9, 100%), with median concentrations of 0.14 µg/kg for beef and 0.48 µg/kg for honey. None of the antimicrobial concentrations found in the beef and egg products exceeded the U.S. FDA's maximum residue limits (MRL). Sulfonamide concentrations were undetectable in the beef and egg products. The concentrations of tetracycline, erythromycin, and sulfonamide spiked into the food products did not change significantly in response to cooking to 160 °F (71 °C). The antimicrobial concentrations found in the selected commercial food products were below the MRL, and cooking appeared to not reduce the spiked antimicrobial concentrations in the evaluated food products.

Antibiotic Residues in Milk and Milk-Based Products Served in Kuwait Hospitals: Multi-Hazard Risk Assessment

Antimicrobial resistance (AMR) poses a significant global health challenge affecting food safety and development. Residues of antibiotics in food from animal sources, particularly milk, contribute to the development and spread of AMR, alter intestinal microbiota, and potentially lead to allergies, serious health conditions, and environmental and technological problems within the dairy industry. Therefore, this study investigated the residue levels of veterinary drugs from β-lactam antibiotics and tetracyclines in milk and milk products and assessed human health risks. Two hundred milk and milk product samples (pasteurized milk, sterile milk, soft white cheese, and processed cheese, 50 each) were collected from different hospitals in the State of Kuwait and screened for antibiotic residues using a microbial inhibition assay (Delvotest SP-NT) and high-performance liquid chromatography (HPLC). Delvotest SP-NT and HPLC analyses showed that 30, 28, 26, and 24% of the pasteurized milk, sterilized milk, white soft cheese, and processed cheese samples tested positive for antibiotic residues. Forty-eight milk and cheese samples were confirmed as positive by both methods, and six samples initially found to be negative by Delvotest SP-NT were confirmed as positive by HPLC. Multi-antibiotic residues were detected in five samples by using HPLC. The kappa coefficient (0.921; p < 0.0001) revealed complete concordance between the HPLC and Delvotest SP-NT results. Ampicillin was the most abundant residue in the positive samples (31.48%), ranging from 2.44 to 3.89 μg/L, with an overall mean concentration of 3.492 ± 0.094 μg/L, followed by tetracycline and oxytetracycline (27.78% each), ranging from 54.13 to 220.3 μg/L and from 41.55 to 160.7 μg/L, with mean concentrations of 129.477 ± 14.22 and 91.86 ± 9.92 μg/L, respectively. The amoxicillin levels in the samples (12/54; 22.22%) ranged from 3.11 to 5.5 μg/L, with an overall mean concentration of 3.685 ± 0.186 μg/L. The maximum concentrations of ampicillin, amoxicillin, and tetracycline were detected in processed cheese with mean concentrations of 3.89 ± 0.28 µg/L, 3.95 ± 0.15 µg/L, and 170.3 ± 0.27 µg/L, respectively. Pasteurized milk contained the maximum concentrations of oxytetracycline, with a mean concentration of 120.45 ± 0.25 µg/L. The tetracycline residues exceeded the standard maximum residue limits (MRLs; 100 µg/L) in 6% of both pasteurized and sterilized milk samples, and in 4% of processed cheese. Additionally, the oxytetracycline levels in pasteurized milk (6%) and amoxicillin levels in processed cheese (2%) were higher than the permitted MRLs (100 µg/L and 4 µg/L, respectively). Furthermore, the antibiotic residues detected in 12.5% (25/200) of the samples were close to standard permissible MRL limits for ampicillin (5%), amoxicillin and oxytetracycline (3% each), and tetracycline (1.5%). Hazard quotients, which compare the standard acceptable daily intake (ADI) to the estimated daily exposure (EDI), indicated that the overall risk associated with antibiotic residues in these dairy products is low. The EDI was lower than the ADI for the tested antibiotics, indicating an elevated safety margin. While the overall hazard quotients are low, the potential for the development of antibiotic resistance due to long-term exposure to low levels of antibiotics should be considered. Hence, strict regulations and enforcement are necessary to prevent excessive residue levels and to promote responsible antibiotic use in dairy production. Regular monitoring of antibiotic residues in dairy products is essential for ensuring consumer safety.

Quantification of antibiotics in food by octahedral gold-silver nanocages-based SERS sensor coupling multivariate calibration

The abuse of antibiotics has caused gradually increases drug-resistant bacterial strains that pose health risks. Herein, a sensitive SERS sensor coupled multivariate calibration was proposed for quantification of antibiotics in milk. Initially, octahedral gold-silver nanocages (Au@Ag MCs) were synthesized by Cu2O template etching method as SERS substrates, which enhanced the plasmonic effect through sharp edges and hollow nanostructures. Afterwards, five chemometric algorithms, like partial least square (PLS), uninformative variable elimination-PLS (UVE-PLS), competitive adaptive reweighted sampling-PLS (CARS-PLS), random frog-PLS (RF-PLS), and convolutional neural network (CNN) were applied for TTC and CAP. RF-PLS performed optimally for TTC and CAP (Rc = 0.9686, Rp = 0.9648, RPD = 3.79 for TTC and Rc = 0.9893, Rp = 0.9878, RPD = 5.88 for CAP). Furthermore, the detection limit of 0.0001 µg/mL for both TTC and CAP was obtained. Finally, satisfactory (p > 0.05) results were obtained with the standard HPLC method. Therefore, SERS combined RF-PLS could be applied for fast, nondestructive sensing of TTC and CAP in milk.

Dietary Exposure to Pesticide and Veterinary Drug Residues and Their Effects on Human Fertility and Embryo Development: A Global Overview

Drug residues that contaminate food and water represent a serious concern for human health. The major concerns regard the possible irrational use of these contaminants, since this might increase the amplitude of exposure. Multiple sources contribute to the overall exposure to contaminants, including agriculture, domestic use, personal, public and veterinary healthcare, increasing the possible origin of contamination. In this review, we focus on crop pesticides and veterinary drug residues because of their extensive use in modern agriculture and farming, which ensures food production and security for the ever-growing population around the world. We discuss crop pesticides and veterinary drug residues with respect to their worldwide distribution and impacts, with special attention on their harmful effects on human reproduction and embryo development, as well as their link to epigenetic alterations, leading to intergenerational and transgenerational diseases. Among the contaminants, the most commonly implicated in causing such disorders are organophosphates, glyphosate and antibiotics, with tetracyclines being the most frequently reported. This review highlights the importance of finding new management strategies for pesticides and veterinary drugs. Moreover, due to the still limited knowledge on inter- and transgenerational effects of these contaminants, we underlie the need to strengthen research in this field, so as to better clarify the specific effects of each contaminant and their long-term impact.

A new PdMOF-loaded molecularly imprinted polyaniline nanocatalytic probe for ultratrace oxytetracycline with SERS technique

In this paper, a new Pd metal organic framework (PdMOF) surface molecularly imprinted polyaniline nanocatalytic probe (PdMOF@MIP) with dual functions of recognition and catalysis was synthesized. It is found that the PdMOF@MIP nanoprobe can not only identify OTC but also catalyze the new nanoreaction of NaH2PO2-HAuCl4 to generate gold nanoparticles (AuNPs), and the generated AuNPs could be traced by surface-enhanced Raman scattering (SERS). When OTC specifically binds to PdMOF@MIP to generate PdMOF@MIP-OTC conjugate, its catalytic effect is weakened and the analytical signal is reduced linaerly. Accordingly, a new, highly sensitive, selective and simple SERS/RRS/Abs trimode detection platform for OTC was constructed. The linear range of SERS was 0.0625 ng/mL ∼ 1.75 ng/mL and the limit of detection was 0.015 ng/mL. This new nanocatalytic probe detection strategy can also be used for the selective detection of other antibiotics such as tetracycline and doxycycline, respectively. In addition, the nanocatalytic mechanism has been investigated.

The two faces of antibiotics: an overview of the effects of antibiotic residues in foodstuffs

Antibiotics, which have been used for many years to treat infections, also play an important role in food contamination with antibiotic residues. There is also unnecessary use of antibiotics, particularly to increase production efficiency. Non-compliance with withdrawal periods and maximum residue limits (MRLs) for antibiotics used in food-producing animals results in undesirable events, such as allergic reactions, teratogenicity, carcinogenicity, changes in the microbiota and, in particular, antibiotic resistance. Therefore, it may be useful to avoid unnecessary use of antibiotics, to limit the use of antibiotics and to turn to alternatives that can be used instead of antibiotics. The aim of this review is to provide information on the undesirable effects of antibiotic residues in food-producing organisms and in the environment, their determination, and the precautions that can be taken.

The Potential of Wood Vinegar to Replace Antimicrobials Used in Animal Husbandry-A Review

The indiscriminate use of antimicrobials in animal husbandry can result in various types of environmental contamination. Part of the dose of these products is excreted, still active, in the animals' feces and urine. These excreta are widely used as organic fertilizers, which results in contamination with antimicrobial molecules. The impacts can occur in several compartments, such as soil, groundwater, and surface watercourses. Also, contamination by antimicrobials fed or administrated to pigs, chickens, and cattle can reach the meat, milk, and other animal products, which calls into question the sustainability of using these products as part of eco-friendly practices. Therefore, a search for alternative natural products is required to replace the conventional antimicrobials currently used in animal husbandry, aiming to mitigate environmental contamination. We thus carried out a review addressing this issue, highlighting wood vinegar (WV), also known as pyroligneous acid, as an alternative antimicrobial with good potential to replace conventional products. In this regard, many studies have demonstrated that WV is a promising product. WV is a nontoxic additive widely employed in the food industry to impart a smoked flavor to foods. Studies have shown that, depending on the WV concentration, good results can be achieved using it as an antimicrobial against pathogenic bacteria and fungi and a valuable growth promoter for poultry and pigs.

Antibiotic residues in milk and dairy products in China: occurrence and human health concerns

Although veterinary antibiotics are essential in preventing and treating clinical diseases in cattle, the frequent use of antibiotics leads to antibiotic residues in milk and dairy products, consequently threatening human health. The massive milk consumption makes it necessary to assess antibiotic pollution and health impact comprehensively. Hence, we conducted a systematic review to evaluate antibiotics in milk and dairy products and their potential health risk. We searched four databases using multiple keyword combinations to retrieve 1582 pieces of literature and finally included eighteen articles to analyze antibiotic residues in milk and dairy products. These studies detected seven antibiotics in different regions of China. Quinolones and β-lactam antibiotics exceeded the MRL for raw and commercial milk. The maximum levels of sulfonamides and tetracyclines were detected in the same raw milk sample, exceeding the MRL. The estimated THQ and HI values in milk and dairy products are less than 1 for adults, indicating negligible noncarcinogenic health risk of antibiotics through consuming milk and dairy products. Children face higher health risks than adults, with the HI and THQ of quinolones exceeding 1. It is worth noting that quinolones accounted for nearly 89% of health risks associated with all antibiotics. Finally, we put forward possible research directions in the future, such as specific health effects of total dietary exposure to low levels of antibiotics. In addition, policymakers should effectively improve this problem from the perspectives of antibiotic use supervision, antibiotic residue analysis in food, and continuous environmental monitoring and control.

Tetracycline residues in fresh dairy milk from three districts in Indonesia: Occurrence and dietary exposure assessment

Background and Aim

Milk can introduce antibiotics into the human diet which poses a public health risk. Therefore, a study to determine the tetracycline residue in dairy milk and its health risk assessment is needed. A cross-sectional study was performed to detect tetracycline residues in fresh dairy milk samples collected from the districts of Malang, Boyolali, and Padang Panjang, Indonesia, and to evaluate dietary exposure to tetracycline residues through milk consumption in 10-12-year-old children and adults.

Materials and Methods

A total of 203 fresh dairy milk samples were collected from local and smallholder dairy cows in Malang, Boyolali, and Padang Panjang in April and August 2018. High-performance liquid chromatography equipped with a photodiode array at 355 and 368 nm was used to detect tetracycline residues. Data were evaluated for dietary exposure assessment.

Results

The results showed that the most common residue found was chlortetracycline (8.37%), followed by tetracycline (7.88%) and oxytetracycline (5.91%) in the concentration range of 14.8-498.4, 11.7-49.4, and 11.6-85.6 ng/g, respectively. Seven (3.45%) samples exceeded the maximum residue limit (MRL) for chlortetracycline. However, neither oxytetracycline nor tetracycline residues exceeded the MRL. The mean concentration of the tetracycline residues was 21.76-137.05 ng/g, resulting in an estimated daily intake of 16.46-172.83 ng/kg body weight/day.

Conclusion

Tetracycline residues were found in almost all milk sampling locations. The highest prevalence and residue concentration were obtained from chlortetracycline. Estimated daily intake of tetracycline through milk by 10-12-year-old children and adult consumers was low and the risk to consumers was negligible.

Sulfonamides and β-lactam antibiotic residues and human health risk assessment in commercial chicken meat sold in Nairobi City, Kenya

The use of antibiotic pharmaceuticals in chicken husbandry has risen steadily over time. Antibiotic residues in chicken meat poses risks to human health in addition to their contribution to the advancement of antibiotic resistance. Despite the increased use of antibiotics in chicken farming in Kenya, assessments of the residues and human exposure have not been conducted. In this study, the sulfonamides (SAs); sulfapyridine (SPD), sulfadiazine (SDZ) and sulfamethazine (SMZ) and the β-lactams (βLs); ampicillin (AMP), penicillin G (PEG) and amoxicillin (AMX) were determined in three chicken meat types; ex-layers, broilers, and indigenous meat marketed in Nairobi City, Kenya. Residual SAs ranged from 0.1 to 154.4 μg kg-1, with SPD recording the highest concentration in ex-layers' chicken meat samples. A range of 19.7 to 309.0 μg kg-1of BLs was found, where the highest amount represented AMX in ex-layers. Mean AMX contents in all chicken types, and AMP in broilers were above the Maximum Residue Limits (MRLs). For SAs, only SPD mean content was above MRL in ex-layers. Human health risks from exposure to antibiotic-contaminated chicken meat was evaluated using % ADI. All tested βLs were of no risk (<1% ADI) to human health. SPD and SDZ posed considerable risk (1-5% ADI) in some chicken meat, whereas SPD in ex-layers' chicken meat posed distinctive risk (>5% ADI) to children. Considering the co-occurrence of different types of antibiotics in same samples, obtained MRLs and % ADI (for some of the antibiotics) are indicative of potential human health risks. Information is valuable in provoking response from concerned agencies and fostering activities that advocate for judicious use of antibiotics.

The influence of subclinical mastitis on the protein composition and protease activities of raw milk from lactating Thai-crossbred dairy cows

Background and Aim

Mastitis in dairy cattle is associated with a high rate of morbidity and death, which has major implications for milk production and quality. This study aimed to investigate the protein component and the activity of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) in raw milk samples with different testing scores determined using the California mastitis test (CMT).

Materials and Methods

Thirty cows were employed in the study, and milk from each quarter was tested for subclinical mastitis (SCM). According to the results of CMT, raw milk samples were classified into five categories: Healthy (score 0), trace (score T), weakly positive (score 1), distinctly positive (score 2), and strongly positive (score 3) for somatic cell count (SCC). The total milk protein was analyzed using the Bio-Rad protein assay, and the milk protein composition was determined using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique. In addition, gelatin zymography was used to evaluate changes in proteolytic abilities.

Results

Milk samples with CMT scores of 1 and 3 had the highest total milk protein levels (32.25 ± 12.60 g/L and 32.50 ± 7.67 g/L, respectively), while the samples from healthy cows (CMT score 0) were only 6.75 ± 1.64 g/L. Globulin and lactoferrin were significantly increased in samples with a CMT score of 3 compared with those with other CMT scores. The bovine serum albumin level in samples with a CMT score of 2 was significantly (p < 0.05) higher than those with other CMT scores. No significant differences in casein abundance were found among samples with different CMT scores. Results from analysis of proteolytic activities demonstrated that the level of MMP-9 in samples with a CMT score of 3 was significantly (p < 0.05) higher than those with other CMT scores.

Conclusion

The protein content and gelatinolytic activity of milk were drastically altered by the number of SCC, mainly due to SCM.

Prevalence and Antibiotic Resistance of Staphylococcus aureus and Escherichia coli Isolated from Bovine Raw Milk in Lebanon: A study on Antibiotic Usage, Antibiotic Residues, and Assessment of Human Health Risk Using the One Health Approach

The emergence, persistence, and spread of antibiotic-resistant microbes is a tremendous public health threat that is considered nowadays a critical One Health issue. In Lebanon, the consumption of raw bovine milk has been recently reported as a result of the financial crisis. The objectives of the current study were (1) to evaluate raw bovine milk samples in a comprehensive manner for the types of antibiotics used and their residues, (2) to determine the presence of mesophilic bacteria, extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA), and (3) to determine the associated human health risk caused by drinking raw milk with antibiotic residues among all age categories. LC-MS-MS was used to carry out the analysis. From 200 milk samples, 30 (15%) were found contaminated with four major antibiotics. The highest average concentration detected was for oxytetracyline 31.51 ± 13.23 μg/kg, followed by 5.5 ± 0.55 μg/kg for gentamicin, 4.56 ± 0.73 μg/kg for colistin, and 4.44 ± 0.89 μg/kg for tylosin. The mean contamination among most samples was below the maximum residue limits (MRLs). Upon comparison with the acceptable daily intake (ADI), the estimated daily intake (EDI) across all age groups was acceptable. The hazard quotient (HQ) was also below 1 across all age groups, signifying the absence of associated health risks for the Lebanese consumers. On the other hand, all milk samples were found exceeding the maximum tolerable value of mesophilic flora. Antibiotic-resistant bacteria (ARB) were detected and represented by ESBL-producing E. coli and MRSA isolates. Thus, the greatest threat of antibiotic use in Lebanon does not fall under antibiotic residues but rather the proliferation of antibiotic resistance in potentially pathogenic bacteria. In this study, the virulence profile of detected bacteria was not investigated; thus their pathogenicity remains unknown. Therefore, to mitigate this health threat in Lebanon, a "One Health" action plan against ABR is required. It will provide a framework for continued, more extensive action to reduce the emergence and spread of ABR in Lebanon.

Impact of Anthropogenic Activities on the Dissemination of ARGs in the Environment-A Review

Over the past few decades, due to the excessive consumption of drugs in human and veterinary medicine, the antimicrobial resistance (AR) of microorganisms has risen considerably across the world, and this trend is predicted to intensify. Many worrying research results indicate the occurrence of pools of AR, both directly related to human activity and environmental factors. The increase of AR in the natural environment is mainly associated with the anthropogenic activity. The dissemination of AR is significantly stimulated by the operation of municipal facilities, such as wastewater treatment plants (WWTPs) or landfills, as well as biogas plants, agriculture and farming practices, including animal production and land application of manure. These activities entail a risk to public health by spreading bacteria resistant to antimicrobial products (ARB) and antibiotic resistance genes (ARGs). Furthermore, subinhibitory concentrations of antimicrobial substances additionally predispose microbial consortia and resistomes to changes in particular environments that are permeated by these micropollutants. The current state of knowledge on the fate of ARGs, their dissemination and the complexity of the AR phenomenon in relation to anthropogenic activity is inadequate. This review summarizes the state-of-the-art knowledge on AR in the environment, in particular focusing on AR spread in an anthropogenically altered environment and related environmental consequences.

Antibiotics in Dairy Production: Where Is the Problem?

Antibiotics have long been used for the prevention and treatment of common diseases and for prophylactic purposes in dairy animals. However, in recent decades it has become a matter of concern due to the widespread belief that there has been an abuse or misuse of these drugs in animals and that this misuse has led to the presence of residues in derived foods, such as milk and dairy products. Therefore, this review aims to compile the scientific literature published to date on the presence of antibiotic residues in these products worldwide. The focus is on the reasons that lead to their presence in food, on the potential problems caused by residues in the characteristics of dairy products and in their manufacturing process, on the development and spread of antibiotic-resistant bacteria, and on the effects that both residues and resistant bacteria can cause on human and environmental health.

Assessment of safety and quality aspects of boiling treatment of quail eggs

A total of 300 quail eggs were collected randomly from different markets in Cairo and Giza Governorates. Five eggs were represented as one egg sample. Shell and content of each egg were examined for their microbiological contents, sensory evaluation and study of Escherichia coli O157 survival in artificially contaminated eggs. Moreover, qualitative detection of antimicrobial residues by seven plates microbiologically bioassay and confirmed by validated high-performance liquid chromatography (HPLC) methods for positively reacted antimicrobials in raw and boiled samples. There was a significant difference (P &lt; 0·05) between the grading score of eggs after the boiling at 2-, 4-, 5- and 7-min. Based on the survival results, the refrigeration storage and boiling for 5 min of quail eggs was confirmed that such eggs are without E. coli O157. After the boil, the concentrations of oxytetracycline (OTC) and 4-Epi-OTC residues were significantly reduced, and there was no effect on the concentration of sulphadimidine (SDD), amoxicillin (AMO) and Diketo residues. Samples that exceeded the maximum residual limits (MRLs) were 17·0%, 12·0%, 10·0%, 16·0% and 14·0% for SDD, OTC, 4-Epi-OTC, AMO and Diketo, respectively. After boiling, no significant change was noted for SDD, AMO and Diketo, but all OTC and 4-Epi-OTC were completely below MRLs. Therefore, SDD and AMO with their metabolite (Diketo) are heat-stable antimicrobial residues with multiple human health hazards.

Inspection of antimicrobial remains in bovine milk in Egypt and Saudi Arabia employing a bacteriological test kit and HPLC-MS/MS with estimation of risk to human health

Veterinary medicine uses antibiotics randomly for treatment and growth promotion. Milk of dairy animals contains substantial quantities of antibiotics that have harmful effects on health. It is therefore necessary to test commercially available milk using immunological, chromatographic, or microbiological methods to confirm the absence of antibiotic residues. This study aims to perform a microbiological test, followed by a quantitative confirmation analysis, on raw milk to assess the presence of antibiotic residues. Tests were conducted on 200 milk samples collected from markets and farms in Saudi Arabia and Egypt. The microbial inhibitor test (Delvotest SP-NT) revealed that 40 samples were positive for antibiotic residues. The positive samples were further tested using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a confirmatory quantitative test for 29 antibiotics that belong to five groups: tetracyclines, sulfonamides, fluoroquinolones, macrolides, and lactamases. Only four samples tested positive for oxytetracycline residues above the maximum residue limit. Based on these results, researchers suggest a monitoring system that considers both microbial and HPLC-MS/MS methods when detecting antibiotic residues in bovine milk. The analysis of risk to human health revealed that antibiotic residues at the detected levels do not pose any health risks to consumers.

Histidine Functionalized Gold Nanoparticles for Screening Aminoglycosides and Nanomolar Level Detection of Streptomycin in Water, Milk, and Whey

Aminoglycoside (AMG) antibiotics are being applied to treat infections caused by Gram-negative bacteria, mainly in livestock, and are prescribed only in severe cases because of their adverse impacts on human health and the environment. Monitoring antibiotic residues in dairy products relies on the accessibility of portable and efficient analytical techniques. Presently, high-throughput screening techniques have been proposed to detect several antimicrobial drugs having identical structural and functional features. The L-histidine functionalized gold nanoparticles (His@AuNPs) do not form a complex with other tested antibiotic classes but show high selectivity for AMG antibiotics. We used ligand-induced aggregation of His@AuNPs as a rapid and sensitive localized surface plasmon resonance (LSPR) assay for AMG antibiotics, producing longitudinal extinction shifts at 660 nm. Herein, we explore the practical application of His@AuNPs to detect streptomycin spiked in water, milk, and whey fraction of milk with nanomolar level sensitivity. The ability of the analytical method to recognize target analytes sensitively and rapidly is of great significance to perform monitoring, thus would certainly reassure widespread use of AMG antibiotics. The biosynthesis of hybrid organic–inorganic metal nanoparticles like His@AuNPs with desired size distribution, stability, and specific host–guest recognition proficiency, would further facilitate applications in various other fields.