Contamination Of Milk Research Articles

Yb-TCPP metal-organic framework as fluorescence sensor for detecting tetracycline in milk.

Developing effective means for detecting contamination in milk during production, processing, and storage is both important and challenging. Tetracycline (TC), due to its use in treating animal infections, is among the most prevalent organic pollutants in milk, posing potential and significant threats to human health. However, efficient and in situ monitoring of TC remains lacking. Nevertheless, we have successfully developed a highly sensitive and selective fluorescence method for detecting TC in milk using a metal-organic framework material made from Yb-TCPP (ytterbium-tetra(4-carboxyphenyl)porphyrin). The calculated Stern-Volmer constant (KSV) was 12,310.88 M-1, and the detection limit was 2.44 × 10-6M, surpassing previous reports. Crucially, Yb-TCPP fluoresces in the near-infrared region, promising its development into a specific fluorescence detection product for practical TC detection in milk, offering potential application value.

Antibiotic residues and microbial contamination in pasteurized whole milk intended for human consumption.

Milk contamination for human consumption is one of the biggest concerns worldwide. To prevent milk contamination, it is important to implement sustainable production practices that ensure animal health and guarantee veterinary drugs have been used properly. This study aimed to detect antibiotic residues and microbial contamination in commercially available pasteurized whole milk intended for human consumption. We conducted a cross-sectional study on all brands of pasteurized milk (n = 17) for human consumption in Medellín, Colombia, from February 30 to April 30, 2022. Six milk samples of each brand were collected every 15 days, resulting in 102 samples. IDEXX SNAPduo™ ST Plus test (IDEXX Laboratories Inc, Maine, USA) was used to detect cephalosporins residues to detect beta-lactam and tetracyclines. We detected mesophilic aerobic bacteria and coliforms using Chromocult Coliform Agar® (Merck KGaA, Darmstadt, Germany) and Plate-Count Agar® (Merck KGaA), respectively. Beta-lactam residues were found in 24.4% of the brands. No tetracyclines or cephalosporins were detected. Mesophilic aerobic bacteria and coliform contamination were detected in 42.6% and 12.8% of the brands, respectively. No fecal coliform contamination was detected. This study demonstrated the presence of antibiotic residues and microbial contamination in commercially available pasteurized whole milk intended for human consumption in the study area, highlighting its potential public health implications.

Investigating the Rate of Contamination of Milk and Traditional Dairy Products with Brucella Bacteria by PCR Method, Mamasani District, Fars Province, South of Iran

Investigating the Rate of Contamination of Milk and Traditional Dairy Products with Brucella Bacteria by PCR Method, Mamasani District, Fars Province, South of Iran

Aflatoxin M1 contamination in milk: A serious issue to be tackled

This comprehensive review addresses the critical issue of Aflatoxin M1 contamination in milk, emphasizing its presence, detection methods, permissible levels, and associated health risks. Aflatoxin M1, a carcinogenic byproduct of Aflatoxin B1, poses significant concerns for the safety of milk, a crucial source of essential nutrients. Regulatory standards from entities like the European Union, U.S. FDA, and FSSAI highlight the need for monitoring and controlling contamination to protect public health. The review extensively explores diverse detection techniques, with ELISA standing out for its speed and precision. Preventive measures, including inhibiting contaminated feed intake, vaccination strategies, and judicious feed usage, are discussed as effective means to minimize Aflatoxin M1 in milk. However, complete elimination remains challenging, leading to the exploration of additional detoxification methods. The review covers various approaches during milk processing, such as pasteurization, sterilization, and the potential roles of probiotics. Absorption materials like bentonite and activated carbon show promise in binding and removing Aflatoxin M1, while chemical approaches with ammonia and hydrogen peroxide are examined with a cautious note on potential risks. Novel detoxification techniques involving plant extracts, including black cumin, garlic, and broccoli, is highlighted for their antioxidant properties. In conclusion, this review provides a foundational understanding of the multifaceted challenge of Aflatoxin M1 contamination in milk, offering insights for future research and the development of effective strategies to ensure the safety and quality of this dietary staple.

Evaluate the aluminum concentrations in whey milk samples of cows from different areas using deep eutectic solvent-based ultrasound-assisted dispersive liquid-liquid microextraction method

This study investigates the contamination of cow milk with aluminum (Al) and its potential health implications, particularly for children. Cow milk samples were collected from both nonexposed and exposed areas in Sindh, based on the source of livestock drinking water (fresh canals and groundwater). An environmental friendly deep eutectic solvent (DES) was used with ultrasonic-assisted dispersive liquid-liquid microextraction (UDLLμE) to enrich trace amounts of Al in whey milk and water samples. The enriched samples were then analyzed using inductively coupled plasma optical emission spectrometry. Certified reference materials were employed to validate the methodology, and the experimental results exhibited acceptable conformity. The DES-based dispersive liquid-liquid microextraction method was environmental friendly, devoid of acids and oxidizing agents, and used safe and inexpensive components for routine trace metal analysis in diverse samples. The resulting data revealed that Al in whey milk samples was observed in the range of 31–45 %, corresponding to (160–270) μg L−1 and (700–1035) μg L−1 in nonexposed and exposed whole cow milk samples, respectively. Additionally, it was observed that milk boiling in Al utensil for 10–20 min enhanced the Al levels from 3 to 8% of its total contents in milk samples.

Exploring the adoption of food safety measures in smallholder dairy systems in Ethiopia: implications for food safety and public health

Milk is highly perishable and can be a conduit for the transmission of zoonotic foodborne pathogens. This cross-sectional survey involving 159 farming households and 18 participant observations in participating farms was undertaken in Addis Ababa and surrounding areas in Oromia, Ethiopia to assess the adoption of food safety measures in smallholder farms. Adoption of food safety measures at the farm level influences milk quality and safety across the entire milk value chain, from “grass to glass”. This study considered the adoption of 36 different food safety measures (FSM) including animal health, milking hygiene, hygienic milk storage, and hygienic milking premises. A weighted food safety index (FSI, ranging from 0 to 100) was calculated for each household based on FSM adopted. Ordinary Least Squares linear regression was used to quantify the factors of FSM adoption by smallholder farmers. The overall food safety index ranged between 59.97—60.75. A majority of farmers may be classified as moderate adopters of FSM (index ranging between 30–70%). Farm and farmers’ characteristics such as herd size, farmer’s education level, farmer’s expertise in dairying, and participation of the farm in the formal milk value- chain, were shown to positively influence the level of adoption of FSM. Low farm-level adoption of FSM has food safety and public health implications as it can lead to milk contamination and, therefore, expose consumers to foodborne diseases. There is an imperative for policymakers to design and implement policies and intervention strategies that lead to increased farmer training related to livestock production and awareness of the important role that FSM adoption can play in improving food safety and public health.

High-grain feeding contributes to endotoxin contamination in dairy milk

To support milk production and milk quality, ruminant animals like dairy cows are particularly fed using concentrate containing high grain and starch. Nonetheless, this type of regimen feeding could induce subacute rumen acidosis condition. Then, these circumstances cause the lysis of gram-negative bacteria accompanied by endotoxin release in gut. More importantly, gut endotoxin could be translocated to mammary gland, whereby this condition negatively affects to milk safety. The aim of the review is to update and summarize the current knowledge regarding high-grain diet and the occurrence of endotoxin in milk of dairy cows. The data suggest that there is interplay between high-grain feeding for dairy cows to endotoxin contamination in milk.

Hygienic Practices of Vendors and Their Contribution to Coliform, Salmonella, and Shigella Bacteria of Raw Milk at Asella Town, Oromia, Ethiopia.

Coliform, Salmonella, and Shigella are among the most encountered bacteria in raw milk. This study is aimed at determining the extent of coliform, Salmonella, and Shigella bacteria in raw milk and vendor hygiene practices at Asella town, Oromia Regional State, Ethiopia, from March 1 to 30, 2022. In this study, 210 milk vendors were included; each vendor provided a 50 ml sample of raw milk. Bacteria were isolated and identified using standard bacteriological techniques. Data were entered and analyzed using EPI info version 7 and SPSS version 22, respectively. A binary logistic regression model was applied to determine the factors associated with bacterial contamination of raw milk. The total contamination percentage of raw milk was 50 (23.8%) (95% CI: 18.1-29.5%). The predominant bacteria identified were coliform 43 (20.5%) followed by Salmonella species 7 (3.3%). Among coliforms, the predominant bacteria were Citrobacter species 15 (34.9%) followed by Enterobacter species 11 (25.6%), Escherichia coli and Serratia species each 6 (14%), and Klebsiella species 5 (11.6%). However, no Shigella was isolated in this study. Not having the habit of washing cow teats (p < 0.0001), the habit of washing teats with tap water (p < 0.0001), not having separate cloth during milking (p < 0.0001), not having a practice of testing milk for bacterial contamination (p = 0.027), and not having separate vending environment (p = 0.039) were significantly associated with bacterial contamination of raw milk. The percentage of bacterial contamination of milk was found to be high. Participants without a habit of washing cow teats, a habit of washing milk utensils with only tap water, and not having separate vending environments were associated factors for bacterial contamination of raw milk. Milk vendors are advised to develop the habit of washing teats before milking, avoid washing teat/milk utensils only with tap water, and have a separate vending environment.

The mechanistic role of natural antimicrobials in preventing Staphylococcus aureus invasion of MAC-T cells using an in vitro mastitis model.

Starting primarily as an inflammation of the mammary gland, mastitis is frequently driven by infectious agents such as Staphylococcus aureus. Mastitis has a large economic impact globally, which includes diagnostic, treatment, and the production costs not to mention the potential milk contamination with antimicrobial residues. Currently, mastitis prevention and cure depends on intramammary infusion of antimicrobials, yet, their overuse risks engendering resistant pathogens, posing further threats to livestock. In our study we aimed to investigate, in vitro, using bovine mammary epithelial cells (MAC-T), the efficacy of the AuraShield an antimicrobial mixture (As) in preventing S. aureus attachment, internalisation, and inflammation. The antimicrobial mixture (As) included: 5% maltodextrin, 1% sodium chloride, 42% citric acid, 18% sodium citrate, 10% silica, 12% malic acid, 9% citrus extract and 3% olive extract (w/w). Herein we show that As can significantly reduce both adherence and invasion of MAC-T cells by S. aureus, with no impact on cell viability at all concentrations tested (0.1, 0.2, 0.5, 1%) compared with untreated controls. The anti-apoptotic effect of As was achieved by significantly reducing cellular caspase 1, 3 and 8 activities in the infected MAC-T cells. All As concentrations were proven to be subinhibitory, suggesting that Ac can reduce S. aureus virulence without bacterial killing and that the effect could be dual including a host modulation effect. In this context, we show that As can reduce the expression of S. aureus clumping factor (ClfB) and block its interaction with the host Annexin A2 (AnxA2), resulting in decreased bacterial adherence in infection of MAC-T cells. Moreover, the ability of As to block AnxA2 had a significant decreasing effect on the levels of pro inflammatory cytokine released upon S. aureus interaction with MAC-T cells. The results presented in this study indicate that mixtures of natural antimicrobials could potentially be considered an efficient alternative to antibiotics in treating S. aureus induced mastitis.

Инфекционные болезни, передающиеся с молоком: обзор литературы

Milk is an excellent nutrient medium in which most saprophytic bacteria and pathogenic microbes grow well under certain conditions. Contamination of milk substrates by microbial pathogens is the cause of the spread of infectious diseases not only from the group of intestinal infections, but also infections with multiple mechanisms of pathogen transmission. Widespread consumption of milk determines the ubiquitination of infectious diseases, in which this product can serve as a factor of pathogen transmission. About 4% of infectious diseases worldwide are associated with milk consumption. The sources of infection are, as a rule, dairy animals, which are the reservoir of pathogens; the factors contributing to the contamination of milk with pathogenic and opportunistic pathogens are technological and sanitary-hygienic violations in the production, storage and sale of dairy products. Despite the fact that the route of transmission of infections with milk is widespread, it is the most underestimated among other intestinal infections. To date, there are no simple and rapid tests to detect the presence of pathogens such as Brucella spp., Coxiella burnetii, Salmonella typhimurium, Campylobacter spp. in milk, the invention of which could significantly reduce the burden of milkborne diseases. This review discusses the epidemiologic importance of milk and milk products in the spread of infectious diseases and possible areas of prevention.

Risk of exposure to aflatoxin M1 through consumption of cow's milk among children in Magadu, Morogoro.

Aflatoxin M1 (AFM1) contamination of milk affects the general population with particular attention to children who frequently consume milk as part of complementary food. This study determined AFM1 contamination of cow's milk and estimated the health risk of dietary AFM1 through consumption of cow's milk among children (6 to 36months) in the Magadu ward of Morogoro region in Tanzania. A total of 165 mother-baby pairs were recruited and interviewed on child feeding practices with a focus on feeding of cow's milk in the past 24h. Alongside the interview, 100 raw cows' milk samples were collected from subsampled respondent households and were analyzed for AFM1 using enzyme-linked immunosorbent assay (ELISA). The results showed that about 35% of the surveyed children consumed cow's milk in the form of plain milk, incorporated in porridge and/or tea. The amount consumed varied from 62.5 to 500 mls with a median of 125 (125, 250) mls at a frequency of 1 to 2 times a day. All raw cows' milk (100%) samples (n = 100) were found contaminated with AFM1 at concentrations ranging from 0.052 to 9.310µg/L and median of 2.076µg/L (1.27, 2.48). All samples were contaminated by AFM1 at levels above the limits of 0.05µg/L of raw milk set by the Tanzania Bureau of Standard and the European Union, while 97% exceeded 0.5µg/L set by the US Food and Drug Administration. Exposure to AFM1 due to consumption of cow's milk ranged from 0.0024 to 0.077 µg/kg bw per day with a median of 0.019 (0.0016, 0.026) µg/kg bw per day, while the margin of exposure (MOE) ranged from 5.19 to 166.76 and median 20.68 (15.33, 25.40) implying high risk of public health concern. This study recommends that advocacy on consumption of cows' milk to combat undernutrition in children should consider a holistic approach that considers the milk's safety aspect.

Layer-by-Layer Biopolymer Assembly for the In Situ Fabrication of AuNP Plasmonic Paper-A SERS Substrate for Food Adulteration Detection.

Here, we introduce an environmentally friendly approach to fabricate a simple and cost-effective plasmonic paper for detecting food additives using surface-enhanced Raman spectroscopy (SERS). The plasmonic paper is fabricated by in situ growth of gold nanoparticles (AuNPs) on filter paper (FP). To facilitate this green fabrication process, we applied a double-layered coating of biopolymers, chitosan (CS) and alginate (ALG), onto the FP using a layer-by-layer (LbL) assembly through electrostatic interactions. Compared to single-layer biopolymer coatings, double-layered biopolymer-coated paper, ALG/CS/FP, significantly improves the reduction properties. Consequently, effective in situ growth of AuNPs can be achieved as seen in high density of AuNP formation on the substrate. The resulting plasmonic paper provides high SERS performance with an enhancement factor (EF) of 5.7 × 1010 and a low limit of detection (LOD) as low as 1.37 × 10-12 M 4-mercaptobenzoic acid (4-MBA). Furthermore, it exhibits spot-to-spot reproducibility with a relative standard deviation (RSD) of 8.2% for SERS analysis and long-term stability over 50 days. This paper-based SERS substrate is applied for melamine (MEL) detection with a low detection limit of 0.2 ppb, which is sufficient for monitoring MEL contamination in milk based on food regulations. Additionally, we demonstrate a simultaneous detection of β-agonists, including ractopamine (RAC) and salbutamol (SAL), exhibiting the multiplexing capability and versatility of the plasmonic paper in food contaminant analysis. The development of this simple plasmonic paper through the LbL biopolymer assembly not only paves the way for novel SERS substrate fabrication but also broadens the application of SERS technology in food contaminant monitoring.

AntimicrobialResistance and Virulence of Shiga-Toxin-Producing Escherichia coli from Milk Samples of Some Cattle Farms Al-Buḥayrah Governorate Egypt

Objective: Contamination of milk with Escherichia coli (E. coli) can pose significant public health and economic concerns. The current study was conducted to explore the prevalence and antibiotic resistance profiles of Shiga-toxin-producing Escherichia coli in milk samples of dairy cows in Egypt. Study Design: Twenty milk samples were gathered from dairy cattle (ten from healthy cows and ten from mastitic cows) and examined for the presence of Shiga-toxin-producing E. coli using Eosin Methylene Blue agar. Molecular detection of virulence genes and phenotypic antimicrobial resistance were performed. Results: E. coli was isolated from 65% (13/20) of the total milk samples (90% from mastitic cows and 40% from normal healthy cows). The virulence gene profiling of E.coli by polymerase chain reaction revealed that 84.62% (11/13) were Stx2a, 69.23% (9/13) were Stx2f, and 61.54% (8/13) were positive for Stx1 and Stx2 similarly. All the isolates showed resistance to Amikacin, Ciprofloxacin, Erythromycin, Linezolid, Penicillin G, and Trimethoprim/Sulfamethoxazole, while 92.3% expressed resistance to Amoxicillin/ Clavulanic acid, and Tylosin, and 84.62% of the isolates were resistant to Oxytetracycline indicating multidrug-resistant profiles. Conclusion: The present work highlights the presence of various E. coli strains, including potential pathogens and multidrug-resistant isolates, in milk samples from dairy cows. Regular milk testing and improved mastitis control measures are the key to reduce the public health risks and to safeguarde dairy farm productivity.

Formulation of Culture Medium for the Enumeration of Lactic Streptococci and Lactobacilli from Fermented Milk Products

Aims: The present study is focused to formulate a single selective differential medium for the enumeration of mixed lactic flora such as lactic streptococci and lactobacilli in domestic and market fermented milk products.&#x0D; Study Design: In order to enumerate lactic streptococci and lactobacilli in a mixed flora of fermented milk, formulation of single selective medium was optimized using inhibitors and indicator instead of separate selective medium for lactic streptococci and lactobacilli.&#x0D; Place and Duration of Study: The present study was conducted in the Department of dairy Microbiology, Dairy Science College, Karnataka Veterinary, Animal and Fisheries Sciences University (KVAFSU), Hebbal, Bengaluru-24, Karnataka from February 2020 to February 2021.&#x0D; Methodology: Fermented milk samples like curd, yoghurt were collected, serially diluted and pour plated using Readymade M17 and MRS agar media and formulated selective yeast glucose agar medium. Lactic colonies obtained were enumerated, expressed as log10cfu/g and critical difference was calculated to declare significance and non-significance among the microbial parameters.&#x0D; Results: Readymade M17 and MRS agar media gave better recovery of viable cells of lactic streptococci and lactobacilli from market samples of curd, yoghurt and domestic curd samples. The study helped to convert a general purpose medium yeast glucose agar as selective differential medium with addition of calcium propionate of 0.8 per cent to avoid Bacillus spore formers and sodium benzoate of 1.2 per cent to inhibit yeast, the common contaminants in fermented milk with 0.05 per cent BCP that led to formation of purple colonies of lactic streptococci and yellow colonies of lactobacilli.&#x0D; Conclusion: The selective yeast glucose agar with 0.8 per cent and sodium benzoate of 1.2 per cent with 0.05 per cent BCP with purple colonies of lactic streptococci and yellow colonies of lactobacilli can be successfully used. This study verified the enumeration of mixed lactic flora in fermented milk products instead of M17 medium for lactic streptococci and MRS for lactobacilli, separately.

Controlling Coxiella burnetii in naturally infected sheep, goats and cows, and public health implications: a scoping review.

Q fever is a worldwide zoonotic disease which domestic ruminants are the main source of infection for humans. This scoping review summarizes the control measures currently available to reduce Coxiella burnetii (Cb) infection in naturally infected sheep, goat and cattle herds. A total of 28 articles were included in the review. A lack of methodological standardization was noted in the articles analyzed. The results indicated that long-term vaccination in cows reduces bacterial excretion in milk and environmental contamination. In small ruminants, the results of vaccination in terms of efficacy are variable. In goats, there is a reduction in bacterial excretion, unlike in sheep, where a long-term vaccination program is necessary to reduce bacterial excretion. Moreover, the high persistence of viable Cb in the environment means that control measures for sheep are needed for several years. The use of antibiotics as a control measure in cows and sheep was not found to reduce excretion. However, the combination of vaccination with antibiotic therapy appears to have positive effects in small ruminants in terms of controlling outbreaks of Q fever. Hygiene and biosecurity measures are the basic means for controlling Cb infection on ruminant farms and ensuring public health.

EFFECT OF 137CS ON FATTY ACID COMPOSITION IN COW`S MILK

Lipid composition of raw milk is a key factor determining the nutritional value and technological suitability of the milk. Monitoring the level of contamination of cow’s milk is often not available for farmers, living in the zone of radioactive contamination. 137Cs activity concentration was higher than permissible level of 100 Bq/kg in all the studied milk samples from all the experimental groups of animals from the studied settlements. The highest value of the 137Cs activity concentration of 600 Bk/kg in cow’s milk was found in Stare Selo village of Rokytne district. According to our study, local animals have partially adapted to the seasonal increase in background radiation, and the milk of these cows, in accordance with existing quality standards, is conditionally suitable for consumption. The only factor prohibiting the consumption of this milk is the level of cesium-137 contamination. An increase in the 137Cs activity concentration of more than 100 Bq/kg in cow’s milk causes a sharp decrease in the relative content of polyunsaturated fatty acids (mostly of omega-6 fatty acids) and changes in the omega-3/omega-6 ratio downward omega-3 relative content. Relative adaptation of the lactating cows to the contamination was revealed; however, metabolism of lipids in the mammary gland and the level of lipids secretion are found to be sensitive to the level of 137Cs contamination of milk. Thus, a violation of the secretory function of the mammary gland was revealed, in particular, metabolism of lipids with 18 carbon atoms in the chain. Relative content of linoleic acid immediately decreases by several times with the increasing the contamination level. Concentration of the stearic acid immediately exceeds the physiological limits at the value of 137Cs activity concentration in milk about 110–130 Bq/kg. It gradually increases with the increasing the 137Cs activity concentration up to 270–330 Bq/kg. And then it is being plateaued with the increasing the 137Cs activity concentration up to 600 Bq/kg. On the base of the study of effect of 137Cs on fatty acid ratio in cow’s milk, the C18-coefficient is being proposed to be used as the parameter of damage to the mammary gland of cows in response to a high level of 137Cs contamination, which is calculated as follows: C18c = (C18:0–C18:2)/100). Determination of the C18-coefficient indicates the dose-dependent effect of the 137Cs contamination on lipid metabolism in the mammary gland and catabolism of polyunsaturated fatty acids, particularly linoleic acid. Duration of the affecting contamination is obviously decisive factor of damage effect to the mammary gland, defining the level of biochemical transformations and initiating of peroxide processes.

Kinetic and proteomic studies in milk show distinct patterns among major Listeria monocytogenes clones

Listeria monocytogenes, a contaminant of raw milk, includes hypervirulent clonal complexes (CC) like CC1, CC4, and CC6, highly overrepresented in dairy products when compared to other food types. Whether their higher prevalence in dairy products is the consequence of a growth advantage in this food remains unknown. We examined growth kinetics of five L. monocytogenes isolates (CC1, CC4, CC6, CC9, and CC121) at 37 and 4 °C in ultra-high temperature (UHT) milk and raw milk. At 4 °C, hypovirulent CC9 and CC121 isolates exhibit better growth parameters in UHT milk compared to the hypervirulent CC1, CC4, and CC6 isolates. CC9 isolate in raw milk at 4 °C exhibited the fastest growth and the highest final concentrations. In contrast, hypervirulent isolates (CC1, CC4, and CC6) displayed better growth rates in UHT milk at 37 °C, the mammalian host temperature. Proteomic analysis of representative hyper- (CC1) and hypovirulent (CC9) isolates showed that they respond to milk cues differently with CC-specific traits. Proteins related to metabolism (such as LysA or different phosphotransferase systems), and stress response were upregulated in both isolates during growth in UHT milk. Our results show that there is a Listeria CC-specific and a Listeria CC-common response to the milk environment. These findings shed light on the overrepresentation of hypervirulent L. monocytogenes isolates in dairy products, suggesting that CC1 and CC4 overrepresentation in dairy products made of raw milk may arise from contamination during or after milking at the farm and discard an advantage of hypervirulent isolates in milk products when stored at refrigeration temperatures.

Listeria Contamination in Milk-Processing Chain and Proficiency in Listeria monocytogenes Decontamination of Small-Scale Milk Retailers

Listeria spp. is an important foodborne bacterium. This microorganism can be discarded from milk using high temperatures such as pasteurization. The milk-processing methods of many small-scale retailers lack quality control. This study was to survey Listeria contamination at the farm and retailer levels. The retailers were to be interviewed for knowledge, attitude, and practice as well. Finally, we were to determine the heating processes employed to decontaminate microorganisms by the retailers using a reference strain of L. monocytogenes. Milk samples were collected from milk-collecting centers and small-scale retailers. In clinical trial, the processing measures were proved for the proficiency in L. monocytogenes decontamination. One out of 99 farms presented Listeria contamination, confirmed to L. marthii. Fifty small-scale retailers participated in the second part, including 13 males and 37 females. No Listeria spp. but Staphylococcus spp. and Bacillus spp. were identified in the processed milk. Data analyses revealed that the location of the retailer was significantly associated with the volume they routinely ordered per lot and the milk-processing time the retailers used to treat milk. Knowledge on raw milk contamination is significantly associated with the stocking or processing of the whole milk lot. Processing measures presale were significantly influenced by the gender of the retailer. The male retailer reportedly spent less time treating milk compared to their female counterparts. To assess the efficacy of the processing methods, a trial using L. monocytogenes as a reference strain was conducted. Interestingly, no L. monocytogenes was detected after sample treatment, but other microorganisms such as S. epidermidis, S. warneri, and Escherichia coli were found, suggesting potential issues with cross-contamination. In conclusion, while the trial implied that the retailers’ processes were effective in L. monocytogenes decontamination, the study highlighted inappropriate practices and the risk of cross-contamination. Continuous monitoring of product safety in small-scale milk retailers is imperative to ensure consumer well-being.

Determination of cypermethrin and hexachlorobenzene levels in milk and dairy products using high-performance liquid chromatography in Isfahan, Iran

ABSTRACT This study aimed to determine the levels of cypermethrin and hexachlorobenzene in milk and dairy products in Isfahan, Iran. In this study, 50 samples including raw milk, pasteurised milk, ultra-high temperature milk, traditional butter, pasteurised butter, traditional cheese, and pasteurised cheese were randomly collected from distribution centres in Isfahan city from June to September 2022. The pesticide levels in the samples were determined using high-performance liquid chromatography. The results indicated that the highest levels of cypermethrin, with 81.02 ± 23.77 µg/kg, were found in traditional butter, pasteurised butter, pasteurised cheese, and traditional cheese, which did not significantly differ. Regarding hexachlorobenzene, traditional butter with 66.68 ± 19.87 µg/kg and pasteurised butter with 47.16 ± 14.45 µg/kg had the highest contamination levels, which were not significantly different. The results indicated contamination of milk and dairy products supplied in Isfahan with pesticide residues.

Isolation, Identification and Antibiogram of Bacteria Isolated from Raw Cow Milk in Dutsin-Ma, Katsina State

The study was conducted to isolate and identify the bacteria, to know the sources of contamination of milk and antibiotic sensitivity of bacteria obtained from Dutsin-Ma, Katsina State. A total of 45 samples were collected from different locations in Dutsin-Ma such as Wednesday market, opposite the FUDMA takeoff site and Hospital road. All these samples were analyzed by culturing in different media such as Salmonella-Shigella agar, Eosin Methylene Blue agar, Mannitol Salt Agar, Nutrient agar, Cetrimide agar, and MacConkey agar. Biochemical tests were performed to identify the organism. Among 45 samples, 20 (37.7%) were Staphylococcus spp. Similarly, 11 (20.8%), 6 (11.3%), 4(7.5%) and 12(22.6%) were found positive for Escherichia coli, Pseudomonas aeruginosa, Klebsiella and Salmonella spp. and. respectively. Results of the antibiotic sensitivity test represent that, out of ten antibiotics Staphylococcus sp. were very sensitive against Gentamicin (95%), Ciprofloxacin (90%), Streptomycin (70%), and highly resistant against Zinnacef (60%), Ampiclox (70%), Amoxicillin (50%). Salmonella sp. were highly sensitive to Pefloxacin (83.3%), Sparfloxacin (83.3%), and Ciprofloxacin (95%), but resistant against Augmentin (83.3%), Streptomycin (75%), Sulfamethoxazole (66.6%). Klebsiella spp. were highly sensitive to Pefloxacin (50%), Sparfloxacin, Chloramphenicol (75%), and Ciprofloxacin (75%), but resistant to Gentamicin (100%), Streptomycin (100%), Sulfamethoxazole (75%), Augmentin (75%). Escherichia coli were highly sensitive to Gentamicin (72.7%), Ciprofloxacin (100%), Ofloxacin (90.9%), Sparfloxacin (72.7%), but highly resistant to Sulphamethoxazole (72.2%), Whereas, Pseudomonas aeruginosa were highly sensitive Ciprofloxacin (100%), Chloramphenicol (66.6%), Ofloxacin (66.6%), but highly resistant against Streptomycin (100%), Augmentin 83.35%), Perfloxacin (83.3%). Data from this study suggested that raw milk contaminated with drug-resistant bacteria may cause public health hazards.