Residues In Raw Milk Research Articles

Detection of antibiotic residues by a novel rapid test in cow’s milk from north Algeria

Detection of antibiotic residues by a novel rapid test in cow’s milk from north Algeria Veterinary treatments, particularly antibiotics used for therapeutic or prophylactic purposes in dairy cattle, can be the cause of antibiotic residues in raw milk. The aim of this study is to investigate the use of antibiotics in the dairy cattle industry and to detect the presence of antibiotic residues in raw milk at collection centers using the SNAPduo ST Plus Test in the Bouira and Bordj Bou Arreridj (BBA) regions of Algeria. The results of the survey of 114 breeders showed that the Montbeliarde and Holstein breeds are the most dominant in the farms studied, the frequency of veterinary interventions in cattle farming is always, the curative veterinary intervention represents the highest rate and the beta-lactam is the most family used with 46.25% in Bouira and 85% in BBA, then the oxytetracycline was 22.5% and 15% respectively. Regarding the use of antibiotics by breeders, the majority of them use antibiotics for their animals, with 76.25% in the region of Bouira and 91% in the province of BBA. The antibiotic test of 122 samples of raw milk showed that 19.67% (24/122) of the samples were positive for antibiotic residues with the beta-lactam showing the highest value (79.16%) followed by tetracycline residues with 20.83%. This study showed the presence of antibiotic residues in raw milk in the study area, which may affect the health of dairy consumers.

Knowledge of Production Conditions and the Quality of Raw Milk Produced in Burundi

In Burundi, despite the socio-economic importance and health impact of milk and dairy products, few researchers are interested in this sector. The few studies concerning the sector are related to the increase in the productivity of dairy cows. However, among all the actions that promote the development of the dairy sector, the improvement of the quality of dairy products constitutes an added value. In view of the above, the objective of this study is to know the production conditions and the quality of raw milk produced in the communes of Kayanza, Ngozi and Bubanza provinces and at the point of reception of raw milk of the Modern Dairy Burundi industry. To this end, a surveys were conducted in 40 dairy farms and carried out physico-chemical measurements on 84 samples of raw milk. The results revealed satisfactory hygiene in 40 farms monitored. The averages were: (i) fat: 46 ± 4g / l, (ii) protein: 29.9±4.7g/l, (iii) pH: 6.7 ± 0.07, (iv) density: 1.031 ± 0.006 and (v) lactic acidity: 16.63 ± 0.92 °D. The antibiotic residues were found in 9 of the 84 samples analyzed, 4 out of 84 samples were positive for alcohol test. It should be remembered that the presence of antibiotic residues in raw milk is an obstacle to processing, especially in the fermentation process. This study aims to contribute to the awareness of stakeholders to adopt good practices throughout the milk production chain in Burundi to better protect the health of consumers.

Colorimetric aptasensor utilizing MOF-235 with exceptional peroxidase-like activity for the detection of oxytetracycline residues in raw milk

In this work, a simple, convenient and cost-effective colorimetric aptasensor was successfully constructed for the detection of antibiotic residues in raw milk based on the property that aptamer (Apt) synergistically enhances the catalase-like activity of MOF-235. Under optimised conditions, the proposed colorimetric aptasensor exhibited a wide detection range (15–1500 nM) with a low detection limit (6.92 nM). Furthermore, the proposed aptasensor demonstrated high selectivity, good resistance to interference and storage stability. The proposed aptasensor was validated by spiking recovery in camel milk, cow milk and goat milk with satisfactory recoveries, which demonstrated the great potential of the aptasensor for further application in real food samples, and also suggested that MOF-235 can be used as a potential universal platform to build a sensitive detection platform for other targets.

Analysis of quality and antibiotic residues in raw milk marketed informally in the Province of Pichincha – Ecuador

ABSTRACT In Ecuador, more than 50% of the milk produced was informally marketed, consequently, the mean of this study was to assess the quality of this milk specifically within the province of Pichincha, the largest milk producer. A total of 650 samples were gathered from the eight cantons within the province. The parameters that exhibited the highest levels of non-compliance, of Ecuadorian legislation, were titratable acidity, accounting for 72.77% of the samples, and protein stability, accounting for 49.34%; these findings indicate a significant presence of bacterial contamination. Concerning antibiotic detection, a frightening 28.46% of the samples tested positive for residues exceeding the maximum limits established by the Codex Alimentarius. The findings indicate that a significant proportion of milk sold through informal channels in Pichincha province-Ecuador poses a substantial risk to public health.

Assessment of Oxytetracycline and Penicillin G Residues Levels in Raw and Fermented Milk in Maiduguri, Northeastern Nigeria

This study was conducted to evaluate the presence and concentration of Oxytetracycline and Penicillin G residues in raw cow and Fermented milk consumed in Maiduguri, Northeastern Nigeria. A total of 172 (86 raw and 86 fermented) milk samples were randomly collected from different milk selling points in Maiduguri. A Spectrophotometer ultraviolet visible spectrum machine was used to detect and quantify the oxytetracycline and penicillin G residues in the milk samples. All samples (raw and fermented milk) tested positive for oxytetracycline and penicillin G residues with a mean residual concentration of 36 µg/L and 20 µg/L in raw and fermented milk respectively for oxytetracycline while the mean residue concentration of penicillin G is 649 µg/L and 397 µg/L in raw and fermented milk respectively. However, the oxytetracycline residues detected were all below the Maximum Residue Level (MRL) standards of 100 µg/L, while the penicillin G residue detected were all above the maximum residue standard of 5 µg/L. The maximum and minimum residue for oxytetracycline detected in raw milk was 79 and 10 (µg/L) respectively while the maximum and minimum residue detected in fermented milk was 42 and 9 (µg/L) respectively. The maximum and minimum residue detected for penicillin G residue in raw milk was 1993 and 767 (µg/L) respectively while the maximum and minimum residue detected in fermented milk was 288 and 164 (µg/L). This study revealed the presence of both oxytetracycline and penicillin G residues in raw and fermented milk consumed in Maiduguri. However, oxytetracycline residues detected in this study were found to be within the acceptable limits, while the penicillin G residues were highly above the MRL standard set by CODEX.

Colloidal Gold Immunochromatography and ELISA Traceability of Tetracycline Residues from Raw Milk to its Dairy Products.

The presence of tetracycline (TC) and its residues in raw milk and milk dairy products poses a threat to human health due to the induction of antibiotic resistance of bacteria that can be transmitted between animals, humans, and the environment. The aim of this study was to investigate the transfer of TC from raw milk to different dairy products: pasteurized milk, boiled milk, sour milk, skimmed milk, and cottage cheese. We analyzed samples of milk from different sources: household farmers, local farms, and milk factories. The analyses of TC in milk and dairy products were performed using colloidal gold immunochromatography assay (GICA) and enzyme-linked immunosorbent assay (ELISA). The highest content of TC was found in the milk purchased from local household farmers; therefore, these samples were chosen for the study of TC transfer to dairy products. TC was also found in sour milk at levels comparable with those obtained in raw milk. The average TC content decreased following heat treatment of the milk, as follows: for pasteurized milk 22.07% and for boiled milk 29.35%. The highest concentrations were determined in cottage cheese in the range 200-620 μg/kg. TC residues are transferred from milk to dairy products in various amounts depending on the preparation conditions, and due to their chemical properties, they accumulate in concentrated derivatives, such as cheese. Therefore, TC can be identified even in cheeses prepared from milk with undetected antibiotic levels.

Detection of Antimicrobial Drug Residues in Raw Cow Milk samples in Logar and Maidan Wardak Province, Afghanistan

Background: Nowadays, various types of antibiotics are being used worldwide in the veterinary sector particularly, for the promotion of growth and treatment of livestock. Significant portions of antibiotics are released through the milk of dairy animals inviolate and exert serious harmful effects on human health. Milk that utilizes by human consumption should also comply with safety criteria regarding antibiotic residues. The objective of this study was to determine the level of antibiotic residues in raw milk conferred by the milk producer’s cooperatives of Logar and Maidan Wardak provinces to Guzargah dairy union for further processing and distribution. Materials and Methods: In this research 110, raw cow milk samples for a one-year period were collected and analyzed (n=110). 55 samples were collected from Logar province and 55 samples were collected from Maidan Wardak province. Milk samples were tested by Betastar Combo Test Kit. All samples considering the laboratory procedures were transported to the laboratory and tested for the presence of Tetracycline and Beta lactams as these antibiotics are widely used for the treatment of bovine mastitis. Finding: Out of 110 milk samples, 12 samples were positive for the presence of Tetracycline residues and 7 samples were positive for the presence of Beta lactams. For further accuracy of the result, all the positive samples were tested by Microbial Inhibition Assay (MIA), and the same result is obtained. Conclusion: The study results show and indicate that antibiotic residues are present in the samples which paves the way for the contamination of human food chains. Considering that milk is mostly consumed by the elderly and kids, hence, it can be the main concern for public health.

Antimicrobial detection from antimicrobial residues in raw milk from dairy farms in western Santa Catarina

Milk is a food rich in nutrients, which makes it widely consumed in Brazil. Its quality is vital for the safety of consumers. Antimicrobial residues may be present in milk if proper management is not performed in administering veterinary drugs to treat dairy cattle, thus representing a risk to human health and generating losses in manufacturing dairy products. Therefore, this study aimed to evaluate the presence of antimicrobials in in natura milk samples from rural properties located western Santa Catarina State using Delvotest® T. Milk samples were collected from October to December 2021. Of the 55 samples collected, 9.1% tested positive for antimicrobial residues, pointing to the need for greater control in the process of antimicrobial administration and control of the waiting period and periodic laboratory analysis. The study allowed one to detect antimicrobial contamination in the sampled milk and emphasized the importance of monitoring and controlling the use of these antimicrobials in rural properties to ensure food safety.

Development of a High-Throughput Screening Analysis for 195 Pesticides in Raw Milk by Modified QuEChERS Sample Preparation and Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry

This study aimed to develop a simple, high-throughput method based on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) followed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) for the rapid determination of multi-class pesticide residues in raw milk. With acidified acetonitrile as the extraction solvent, the raw milk samples were pretreated with the modified QuEChERS method, including extraction, salting-out, freezing, and clean-up processes. The target pesticides were acquired in a positive ion electrospray ionization mode and an All ions MS/MS mode. The developed method was validated, and good performing characteristics were achieved. The screening detection limits (SDL) and limits of quantitation (LOQ) for all the pesticides ranged within 0.1–20 and 0.1–50 μg/kg, respectively. The recoveries of all analytes ranged from 70.0% to 120.0% at three spiked levels (1 × LOQ, 2 × LOQ, and 10 × LOQ), with relative standard deviations less than 20.0%. The coefficient of determination was greater than 0.99 within the calibration linearity range for the detected 195 pesticides. The method proved the simple, rapid, high throughput screening and quantitative analysis of pesticide residues in raw milk.

A Simple Yet Effective Preanalytical Strategy Enabling the Application of Aptamer-Conjugated Gold Nanoparticles for the Colorimetric Detection of Antibiotic Residues in Raw Milk.

The misuse of antibiotics in the cattle sector can lead to milk contamination, with concomitant effects on the dairy industry and human health. Biosensors can be applied in this field; however, the influence of the milk matrix on their activity has been poorly studied in light of the preanalytical process. Herein, aptamer-conjugated gold nanoparticles (nanoaptasensors) were investigated for the colorimetric detection in raw milk of four antibiotics used in cattle. The effect of milk components on the colorimetric response of the nanoaptasensors was analyzed by following the selective aggregation of the nanoparticles, using the absorption ratio A520/A720. A preanalytical strategy was developed to apply the nanoaptasensors to antibiotic-contaminated raw milk samples, which involves a clarification step with Carrez reagents followed by the removal of cations through dilution, chelation (EDTA) or precipitation (NaHCO3). The colorimetric signals were detected in spiked samples at concentrations of antibiotics as low as 0.25-fold the maximum residue limits (MRLs) for kanamycin (37.5 μg/L), oxytetracycline (25 μg/L), sulfadimethoxine (6.25 μg/L) and ampicillin (1 μg/L), according to European and Chilean legislation. Overall, we conclude that this methodology holds potential for the semiquantitative analysis of antibiotic residues in raw milk obtained directly from dairy farms.

Estimation and human health risk assessment of organochlorine and organophosphate pesticide residues in raw milk collected in Kenya

Background: This study determined the levels of organochlorine (OCPs) and organophosphate (OPPs) pesticide residues in cow milk from Kiambu and camel milk from Isiolo and Laikipia. The human dietary intake and the potential consumer health risks were also evaluated. Methods: In total, 90 cow and 82 camel milk samples were collected and analyzed using gas chromatography tandem mass spectroscopy to determine the levels of OCPs and OPPs. The levels were compared to the maximum residue limits (MRLs) established by the Codex Alimentarius (CA), EU Pesticides Database (EUPD), and the United States Department of Agriculture. The estimated daily intake and chronic hazard quotient (cHQ) of the milk were also calculated. Results: Cow milk from Kiambu was contaminated with 11/18 of the evaluated OCPs and 13/14 of the evaluated OPPs while camel milk from Isiolo was contaminated with 9/18 of the evaluated OCPs and 9/14 of the evaluated OPPs. Camel milk from Laikipia was contaminated with 11/18 of the evaluated OCPs and 11/14 of the evaluated OPPs. The mean heptachlor value in camel milk from Isiolo was above the EUPD MRLs. The mean value of heptachlor in Camel milk from Laikipia was above the CA and EUPD MRLs. The cHQs for Disulfoton, Fenamiphos, and Methacrifos in Cow milk were above 1 for adults and children. The cHQs for Fenchlorphous and Profenofos in Camel milk were above 1 for adults and children. The cHQs for α-endosulphan, β-endosulphan, dieldrin, and heptachlor in cow milk was above 1 for adults and children while the cHQs for heptachlor in camel milk was above 1 for adults and children. Conclusions: The potential health risks from chronic dietary intake of cow and camel milk in Kenya cannot be excluded. The routine monitoring of organophosphate and organochlorine pesticide levels in milk is recommended to minimize risks to human health.

Comparative Assessment of Antibiotic Residues Using Liquid Chromatography Coupled with Tandem Mass Spectrometry (LC-MS/MS) and a Rapid Screening Test in Raw Milk Collected from the North-Central Algerian Dairies.

Antibiotic residues in milk are a major health threat for the consumer and a hazard to the dairy industry, causing significant economic losses. This study aims to assess the presence of antibiotic residues in raw milk comparatively by a rapid screening test (BetaStar® Combo) and Liquid Chromatography coupled with Tandem Mass Spectrometry (LC-MS/MS). A total of 445 samples were collected from 3 dairy companies of north-central Algeria (Algiers, Blida, Boumerdes), and they were rapidly screened for β-lactams and tetracyclines; 52 samples, comprising 34 positive tanker-truck milk and 18 negative bulk-tank milk were tested by LC-MS/MS, which revealed 90.4% were contaminated (n = 47) and 55.3% exceeded the Maximum Residue Limit (MRL). The β-lactams as parent compounds and their metabolites were the most frequently detected with maximum value for cloxacillin (1231 µg/kg) and penicillin G (2062 µg/kg). Under field condition, the false-positive results, particularly for tetracyclines, seems to be related to milk samples displaying extreme acidity values (≥19°D) or fat-level fluctuations (2.7 g/100 mL and 5.6–6.2 g/100 mL). Despite a relatively low prevalence (7.64%) of residues using the rapid test, the detection by LC-MS/MS of flumequine (52 µg/kg), cefaclor (maximum 220 µg/kg) and metabolites of β-lactams at high levels should lead to reflections on the control of their human and environmental toxicological effects.

English

The mastitis causing microorganisms resist beta-lactam antibiotics by releasing beta-lactamase and the enzyme can be traced in raw milk. This study was aimed at developing a novel platform test to detect beta-lactam antibiotics residues in raw milk based on the Hardy Diagnostic Beta-lactamase Test (HDBT) reagent. The HDBT ingredients modified were penicillin, sodium chloride, trisodium citric acid, trisodium phosphate and phenol red dissolved in distilled water. Pooled raw milk samples were obtained from 3 Friesians and 3 Ayrshires lactating cows identified to have subclinical mastitis and treated using beta-lactam antibiotics. The appropriate mixing ratios were investigated at nine levels. Investigation on the effect of breeds on the test method results was also carried out. Evaluations to determine the colour differences between beta-lactam positive and negative raw milk samples for all the experiments were carried out using trained panelists. The results indicate that gradual addition of trisodium phosphate and phenol red in the reagent showed significant difference (P ≤ 0.05) between a beta-lactam positive and negative raw milk sample. Ratio 5:5 was selected as the best and had significant difference (P ≤ 0.05) from the others. Conversely, the test method indicated no significant difference (P ≤ 0.05) between the Friesians and Ayrshires raw milk samples. This method can be used along the raw milk collection routes to accept, set aside or reject raw milk suspected to have residues. The colour observed for a beta-lactam negative sample was fuchsia purple while peach or pink signified a positive sample.   Key words: Raw milk, antibiotic residues, beta-lactam, beta-lactamase enzyme, trisodium phosphate

Notice of correction: The Effect of Boiling on Stability of Oxytetracycline and Sulfamethazine Residues in Raw Milk using HPLC Method

Notice of correction: The Effect of Boiling on Stability of Oxytetracycline and Sulfamethazine Residues in Raw Milk using HPLC Method

Screening of antibiotic residues in raw milk of cows and buffalos by diffusion assays.

Although antibiotics are valuable drugs for treatment of certain infections, their presence in foodstuff derived from animals is a potential public health hazard. They pose a serious threat as they are implicated in direct toxicity; allergic reactions; disturbance of the normal gut microbiota, carcinogenesis, and emergence of antibioticresistant bacteria. This study investigated the occurrence of antibiotic residues in raw milk samples derived from cows and buffaloes. Samples were collected randomly from different retail outlets in Erbil city (Iraq) from January 1st to June 30th, 2019. The residues were detected by two diffusion assays against Bacillus subtilis bacteria on agar plates. The total occurrence of residues ranged from 11.9% to 13.4% of screened milk samples. No significant differences were found between milk type or location of animal rearing (urban or suburban). Regarding the seasonal variations, spring was found to be associated with gradual decrease in antibiotic residues levels in milk. Such occurrence rate of residues is alarming and require authorities to observe the quality of raw milk introduced to markets for consumption. Further evaluation of antibiotic stability period in raw milk is also necessary.

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

Consumption of milk contaminated with antibiotic residues above the maximum residue limit (MRL) causes toxicity to humans and the development of superbugs that leads to the failure of antibiotic therapy and threatens human life. Moreover, long-duration exposure might alter the nature of gut microflora, resulting in the enhancement of many diseases. Therefore, our study aims to find out the residues level of selected antibiotics in milk and assessments of humans health risks. We examined 300 raw and processed milk samples using thin-layer chromatography (TLC) and ultra-high-performance liquid chromatography (UHPLC) methods against five veterinary antibiotics and assessed the health risk for consumers in Chattogram, Bangladesh. Risk analysis was done by using a hazard quotient based on 165 ml per capita milk consumption. We found a total of 7 % prevalence of antibiotic residues in raw milk, which were higher (8 %) in individual milk samples than the pooled samples (4 %). However, we did not find any antibiotic residues in processed milk. The mean concentration of oxytetracycline residue was detected at 61.29 μg/l, and amoxicillin was 124 μg/l in individual milk samples. Risk analysis showed that, the hazard quotient values are 0.0056 for oxytetracycline and 0.0017 for amoxicillin residues. This result implied no significant health risks associated with the consumption of milk produced and marketed in the study area. Our study might fill up the gaps of knowledge in measuring the safety status of milk regarding public health issues.

Control of antibiotic residues in raw milk in a dairy industry from Jalisco, Mexico: a retrospective study

The current regulation in Mexico is explicit about the prohibition of the presence of antibiotic residues in raw cow's milk. Due to the impact of the presence of antibiotic residues in milk in the production of dairy products, some dairy companies have implemented their own programs to control antibiotic residues to avoid collection of contaminated material. The aim of this study was to analyze the results of the implementation of a program to control the presence of antibiotic residues in raw cow´s milk collected by a big local dairy industry. During the applications of this program, the frequency of contaminated milk containing the two main groups of antibiotics: β-lactams and tetracyclines, in 9 concentration facilities of a local dairy company, with an average size receiving 800,000- 1,000,000 L/day during 5 years. The antibiotic residue detection was performed using SNAP® Beta-Lactam Test and SNAP® Tetracycline Test simultaneously. During the first year, 222 tanks (2,955,538 L) were tested, of them 93 were positive for antibiotic residues (42.11%). In the fifth year, from 889 tanks containing 5,658,062 L only 13 were positive (1.46%), obtaining a reduction rate of 10.16% annual average. When the companies control the presence of inhibitor residues in the raw milk buy the milk, the farmers discard the contaminated milk; however, they sell it even with antibiotics when the buyers do not carry out controls, so this control measure becomes a solution. The results showed a significant decrease in contamination, being a useful solution to the problem of the appearance of antibiotic residues in milk in the raw material of the plant.

Metronidazole Determination in Raw Milk with a Graphene Aerogel-Based Electrochemiluminescent Sensor and Its Effect on Cell Apoptosis

Herein an electrochemiluminescence (ECL) sensor based on graphene aerogel (GA) for detecting metronidazole (MTZ) was proposed. The ECL behavior of the Ru(bpy)32+-doped silica nanoparticles (SiO2@Ru(bpy)32+ NPs) was investigated with MTZ as the coreactant. Quantitative detection of MTZ was realized as MTZ could effectively enhance the ECL signal of the SiO2@Ru(bpy)32+ NPs. A wide linear range of 2.5 to 250 μM (r = 0.9937) was obtained under optimized conditions, and a detection limit (S/N = 3) was achieved as low as 0.5 μM. Finally, the analytical application of the proposed sensor was evaluated by detecting a drug sample and MTZ residues in raw milk. Additionally, MTZ was an apoptosis inducer toward MCF-7 cells, and our method could measure the accurate concentration of MTZ which can cause serious apoptosis in cellular experiments. Thus, with good stability, acceptable precision, and reproducibility, the proposed sensor supports promising practicability in clinical analysis.

Contribution to the Identification of Antibiotics Residues in Raw Bovine Milk in Algeria

The presence of residues of veterinary drugs such as antibiotics used for the treatment of animals can be dangerous for the consumer. Indeed, residues of these drugs can end up in the form of undesirable traces in animal productions, in particular milk when there is an inappropriate use such as failure to comply with the waiting times between the administration of antibiotics to the animal and meat collection. This study is part of a global project carried out with the aim of evaluating the presence of antibiotic residues in the raw milk of cows reared in cattle farms in Blida. This study involved 200 milk samples were collected in the Wilaya of Blida. A screening of the samples was carried out by the acidification test followed by a confirmation agar diffusion test. The results showed residues in 20,51 % of the milk tested. The study revealed the presence of antibiotic residues in raw cow’s milk from farms in varying proportions. Penicillin residues and / or tetracyclines were originally of the contamination of 93,62 % milk samples positive while residues macrolide and / or aminoglycoside were only detected in 6,38 % of samples tested positive. The use of antibiotics should be done by veterinarians or under their responsibility by animal health professionals.

187 Protocols, standard operating procedures, and employee training to improve milk safety and quality

Abstract Dairy farm employees play a key role in ensuring the highest quality milk being delivered to manufacturers. Major concerns associated with milk quality on dairies include the number of clinical mastitis cases, elevated somatic cell counts, elevated bacteria count, and presence of residues in raw milk. All these factors are impacted by the knowledge, skills, and performance of dairy employees working in the milking parlor and other areas of the operation. Exemplary performance on dairies is driven by effective training, motivation, and communication between various team members. Standard operating procedures (SOPs) provide a basis for training employees, improving consistency between and within shifts, and conducting performance evaluations with valuable feedback. SOPs also have the potential to improve milk quality, herd performance, and herd health. SOPs should be specific to the dairy operation and developed with detailed instructions on completing a task. These procedures need to be written in the employees’ native language in addition to English and should be easy to read and understand. The font used should be large and when appropriate, photos should be used to explain or highlight step by step procedures. Once developed, SOPs need to be evaluated at least once a year and revised as needed. Regular trainings are also important for prevention of procedural drifts. Hybrid learning models combining classroom/online and hands-on activities should be considered and implemented. This approach ensures that dairy employees are engaged and appropriately trained, independent of their literacy and reading proficiency. Dairies should also strive to provide a positive, safe, and comfortable work environment for their employees. A positive environment can lead to improvements in employee morale, performance, and retention. Finally, it is important to establish clear and firm expectations on producing the highest quality of milk while providing specific, timely, and constructive feedback.