Milk Agent Research Articles

Contamination of food products with Mycobacterium avium paratuberculosis: a systematic review

Although a causal link between Mycobacterium avium subspecies paratuberculosis (MAP) and Crohn's disease has not been proved, previous studies suggest that the potential routes of human exposure to MAP should be investigated. We conducted a systematic review of literature concerning the likelihood of contamination of food products with MAP and the likely changes in the quantity of MAP in dairy and meat products along their respective production chains. Relevant data were extracted from 65 research papers and synthesized qualitatively. Although estimates of the prevalence of Johne's disease are scarce, particularly for non-dairy herds, the available data suggest that the likelihood of contamination of raw milk with MAP in most studied regions is substantial. The presence of MAP in raw and pasteurized milk has been the subject of several studies which show that pasteurized milk is not always MAP-free and that the effectiveness of pasteurization in inactivating MAP depends on the initial concentration of the agent in raw milk. The most recent studies indicated that beef can be contaminated with MAP via dissemination of the pathogen in the tissues of infected animals. Currently available data suggests that the likelihood of dairy and meat products being contaminated with MAP on retail sale should not be ignored.

Characterization of bacterial population of raw milk from bovine mastitis by culture-independent PCR–DGGE method

Culture-independent PCR–DGGE fingerprinting was used to reveal the bacterial composition and diversity associated with raw milk of mastitis-infected cows from Hokkaido, Japan for the first time. All the mastitic milk samples were diagnosed as solely infected by coliforms using the classical microbiological method following on-farm culturing. The variation in community structure between each sample observed in our results indicated that the bovine mastitis-associated bacteria were host-specific. Klebsiella pseudomoniae, Lactococcus lactis, Staphylococcus aureus and members of the Escherichia genus were found to be widely distributed. Furthermore, more than one pathogen known to cause mastitis was found to be present in some milk samples. These pathogens are not only potential etiological agents but may also play a role in disrupting the natural microbial ecology in mastitic cows. This finding highlights the limitation of the traditional identification and characterization strategy, and the PCR–DGGE are shown to be a powerful tool for describing the bacterial flora and especially etiological agents in mastitic milk.

Electron microscopic studies on cancer cells. 3. Ultra-cell structures of C3H milk agent strain breast carcinoma of mice as revealed by electron microscope.

Electron microscopic studies on cancer cells. 3. Ultra-cell structures of C3H milk agent strain breast carcinoma of mice as revealed by electron microscope.

Chemistry and Biological Properties of Human Milk

Human milk contains several solid components, water, and wide range of bioactive compounds. Over the evolutionary course of human development, a number of adaptations have resulted in the production of nonnutritive actions associated with breast feeding. In that regard, bioactive compounds in human milk appear not only to compensate for developmental delays in the infants gastrointestinal tract but also encourage the symbiotic colonization of enteric bacteria that inhibit the growth of bacterial and viral pathogens. Research has also linked these bioactive compounds to certain aspects of the growth and proper development of brain and peripheral nervous system during early infancy. In this review we have summarized what has been learned about the spectrum of nutritive and biological agents in human milk, their physical distribution in human milk over the course of lactation, whether the physical structures and functions of these ingested agents are modified by digestive processes; the precise chemical and cellular loci of their actions, and their short- and long-term biochemical consequences. Although much is still unknown about human milk, and how to optimize infant nutrition substitutes, new information is constantly being discovered. Human milk is and will remain the one standard for infant nutrition by which all infant foods should be compared. It is our species-specific food. Keywords: Human milk, bioactive compounds, breast feeding, viral pathogens, infant nutrition, Biological Properties

Determination of Quinolones and Nonsteroidal anti‐Inflammatory Agents in Animal Tissues and Bovine Milk by Microwave‐assisted Extraction High Performance Liquid Chromatography

Determination of Quinolones and Nonsteroidal anti‐Inflammatory Agents in Animal Tissues and Bovine Milk by Microwave‐assisted Extraction High Performance Liquid Chromatography

Antiinfective Properties of Human Milk1,

The unfavorable effects of neonatal immunodeficiency are limited by some naturally occurring compensatory mechanisms, such as the introduction of protective and immunological components of human milk in the infant. Breast-feeding maintains the maternal-fetal immunological link after birth, may favor the transmission of immunocompetence from the mother to her infant, and is considered an important contributory factor to the neonatal immune defense system during a delicate and crucial period for immune development. Several studies have reported that breast-feeding, because of the antimicrobial activity against several viruses, bacteria, and protozoa, may reduce the incidence of infection in infants. The protection from infections may be ensured either passively by factors with antiinfective, hormonal, enzymatic, trophic, and bioactive activity present in breast milk, or through a modulator effect on the neonatal immune system exerted by cells, cytokines, and other immune agents in human milk.

ENDOGENOUS RETROVIRUSES IN SYSTEMIC RESPONSE TO STRESS SIGNALS

Infection of germline cells with retroviruses initiates permanent proviral colonization of the germline genome. The germline-integrated proviruses, called endogenous retroviruses (ERVs), are inherited to offspring in a Mendelian order and belong to the transposable element family. Endogenous retroviruses and other long terminal repeat retroelements constitute ~8% and ~10% of the human and mouse genomes, respectively. It is likely that each individual has a distinct genomic ERV profile. Recent studies have revealed that a substantial fraction of ERVs retains the coding potentials necessary for virion assembly and replication. There are several layers of potential mechanisms controlling ERV expression: intracellular transcription environment (e.g., transcription factor pool, splicing machinery, hormones), epigenetic status of the genome (e.g., proviral methylation, histone acetylation), profile of transcription regulatory elements on each ERV's promoter, and a range of stress signals (e.g., injury, infection, environment). Endogenous retroviruses may exert pathophysiologic effects by infection followed by random reintegration into the genome, by their gene products (e.g., envelope, superantigen), and by altering the expression of neighboring genes. Several studies have provided evidence that ERVs are associated with a range of pathogenic processes involving multiple sclerosis, systemic lupus erythematosus, breast cancer, and the response to burn injury. For instance, the proinflammatory properties of the human ERV-W envelope protein play a central role in demyelination of oligodendrocytes. As reviewed in this article, recent advances in ERV biology and mammalian genomics suggest that ERVs may have a profound influence on various pathogenic processes including the response to injury and infection. Understanding the roles of ERVs in the pathogenesis of injury and infection will broaden insights into the underlying mechanisms of systemic immune disorder and organ failure in these patients.

TRANSMISSION OF HELICOBACTER PYLORI INFECTION IN MOTHER-INFANT PAIRS

INTRODUCTION: Various pathways, such as person-person, fecal-oral, and oral-oral transmission, play a role in transmission of Helicobacter pylori infection. It can be transferred from mother to infant in either the perinatal or postnatal periods. OBJECTIVE: The aim of this prospective study was to determine the course of H pylori infection in mother-infant pairs in early years of life. METHODS: Forty-eight mother-child pairs were followed for 12 months. H pylori and hepatitis A virus immunoglobulin G levels were measured in maternal sera, infant sera, and breast-milk samples at birth and in breast-milk samples and infant sera at follow-up visits. RESULTS: At birth, the seropositivity for H pylori was 81.25% and hepatitis A was 68.75% in breast milk and 95.8% in maternal and infant sera for both microorganisms. Although there was a decrease in seropositivities for both agents in both infant sera and breast milk at the age of 9 months, an increase was observed in the twelfth month. CONCLUSIONS: High seroprevalence rates of H pylori and hepatitis A virus and similar monthly changes in seroprevalence could be indicators of the same transmission routes.

REDUCING METHOD OF CEMENT SLURRY INJECTION VOLUME USING FLUIDIZING AGENT IN SOIL CEMENT WALL CONSTRUCTION

Soil cement wall construction works for earth retaining wall bring about a huge quantity of construction sludge. In order to reduce the construction sludge, the reducing method of cement slurry injection volume using fluidizing agent in cement milk was developed. In this paper, outline and characteristic of the agent, the performance of the agent in laboratory tests, and the efficacy of reducing method with the agent in field construction tests are presented.

Risk Factors in the Hygienic Quality of Milk in Ghana

The study was carried out to identify risk factors associated with bacterial contamination of locally produced raw milk and its adulteration with water. A total of 419 respondents of different categories of milk agents in the study sites were sampled for data and milk collection in the dry and wet seasons. The data collected focused on milk marketing factors and handling practices likely to affect milk quality, while the milk samples were analysed to determine the extent of bacterial contamination and adulteration with water. The proportion of milk samples adulterated was 18%. While 23.5% of the milk samples had unacceptably high total plate count (>6.3 log10 cfu/ml), all the samples had unacceptably high coliform plate count (>0.7 log10 cfu/ml). Risk factors associated with high bacterial counts were related to milk mar- keting channels (p<0.05), milk market agents (p<0.01), and milk containers (p=0.06) as well as their mode of cleaning (p=0.06). The only risk factor identified for adulteration of milk was related to season (p=0.04). associated with poor hygienic quality. The findings would help in the formulation of appropriate recommendations to improve the hygienic quality of informally marketed milk in Ghana, which could go along way to stimulate growth of the dairy industry.

Performance of Blue-Yellow Screening Test for Antimicrobial Detection in Ovine Milk

Drug residues in milk are important because of public health and industrial implications. The detection limits of 25 antimicrobial agents were determined by the blue-yellow screening method in ovine milk. For each drug, 8 concentrations were tested on 20 ovine milk samples from individual ewes in midlactation. Detection limits determined by means of logistic regression were below European Union maximum residue limits (EU-MRL) for penicillin G (3 to 4μg/kg), ceftiofur (96 to 107μg/kg), framycetin (720 to 781μg/kg), neomycin (915 to 1,084μg/kg), and tylosin (44 to 51μg/kg). Detection limits for ampicillin (5 to 6μg/kg), cloxacillin (33 to 42μg/kg), cefoperazone (73 to 82μg/kg), cefalexin (160 to 202μg/kg), gentamycin (355 to 382μg/kg), streptomycin (3,063 to 3,593μg/kg), tilmicosin (109 to 131μg/kg), erythromycin (444 to 522μg/kg), spyramicin (1,106 to 1,346μg/kg), sulfadimethoxine (101 to 119μg/kg), sulfathiazole (122 to 151μg/kg), sulfamethazine (309 to 328μg/kg), sulfanilamide (1,750 to 2,674μg/kg), tetracycline (233 to 257μg/kg), oxytetracycline (398 to 501μg/kg), doxycycline (323 to 419μg/kg), chlortetracycline (3,331 to 3,989μg/kg), danofloxacin (4.7 to 5.5 mg/kg), enrofloxacin (41 to 46 mg/kg), and flumequin (63 to 71 mg/kg) were higher than the EU-MRL. Although the blue-yellow method showed improved sensitivity compared with other tests studied in ovine milk, the performance of screening methods for detecting antimicrobial agents in milk of this species should be improved.

Testing for Antibodies to &lt;i&gt;Brucella abortus&lt;/i&gt; in Milk From Consumers and Market Agents in Kenya Using Milk Ring Test and Enzyme Immunoassay

Over 85% of all milk sales on Kenya pass through informal channels. The extent of the risk posed by the sale of this raw milk to human health in respect to brucellosis is unknown. This paper presents the results of a study on the occurrence of antibodies to Brucella abortus in milk from households consuming raw unpasteurized milk and market agent selling the same. Four hundred thirty four (434) raw milk samples from consumer households and 508 from informal market agents were collected between January 1999 and January 2000 from Nakuru /Narok and Nairobi/Kiambu. Milk agents sampled included co-operative societies, milk collecting centers and self-help groups, milk bars, shops and kiosks and mobile traders on foot, bicycle or motorized transport. In addition, 147 samples from the formal market chain (pasteurized) were collected. All the samples from the samples were screened for antibodies to Brucella abortus using ELISA and Milk Ring Test (MRT), except for the formal milk that was tested using ELISA only. Five percent of the consumer household samples and 4% of the samples form informal milk market agents tested positive on ELISA. There was poor agreement between the two antibody surrogate tests (Kappa =0.40, 95% confidence interval =0.19-0.60). ELISA detected 3.2% more samples from consumer households and 0.4% from informal market agents than MRT. Of the formal market samples, 16.4% were positive. Ways of reducing the risk of contracting brucellosis from drinking raw milk are proposed. The Kenya Veterinarian Vol. 27 2004: pp. 18-21

Performance and behavior of dairy calves fed diets containing milk and citric flavor agents

While young ruminants prefer milk aroma and researches about this theme are being developed, the use of citric aroma, very appetized for older ruminants, are low utilized to young animals. This work aims to compare the influence of milk and citric flavor agents on the diets of nursing dairy calves. In this trial, 12 animals of Holstein breed were distributed in a randomized block design with four treatments (concentrate without flavor agent, concentrate with milk flavor or citrus flavor, and concentrate with milk plus citrus flavor agent) and three repetitions. The parameters evaluated were: concentrate dry matter intake (CDMI), hay dry matter (HDMI), milk dry matter intake (MDMI) and total dry matter intake (TDMI), average weight gain (ADWG), feed conversion (FC), initial (IBW) and final body weight (FBW), initial thoracic perimeter (ITP) and final thoracic perimeter (FTP), initial abdominal perimeter (IAP) and final abdominal perimeter (FAP), initial withers height (IWH) and final withers height (FWH) and animal behavior. The CDMI, HDMI and TDMI, as well as IBW, FBW, ITP, FTP, IAP, FAP, IWH and FWH did not show differences (P&gt;0.05). The averages daily gain and feed conversion showed no differences, with means of 0.55 kg/animal and 2.09, respectively. The diets did not affect animal behavior parameters (P&gt;0.05).

Changes in mammary uptake and metabolic fate of glucose with once-daily milking and feed restriction in dairy cows

The aim of this review is to better understand the regulation of milk yield in response to once-daily milking and feed restriction. Glucose is the principal precursor for the synthesis of lactose (a major osmotic agent in milk), and participates in determining the milk volume produced. When applying these two breeding factors, reductions in milk yield are associated with a reduction in milk lactose yield and in the arterial flow of glucose, due to a decrease in the mammary blood flow. The ability of the udder to extract glucose is altered with once-daily milking but not necessarily with feed restriction. Lactose synthesis is down-regulated in response to once-daily milking and feed restriction but the percentage of the extracted glucose which is converted into lactose is differently affected in response to treatments. No marked change is observed with once daily milking whereas this would be increased with feed restriction and in contrast, depressed with fasting.

Levels of Cytokines (IL‐1β, IL‐2, IL‐6, IL‐8, TNF‐α) and Trace Elements (Zn, Cu) in Breast Milk From Mothers of Preterm and Term Infants

It has been well documented that human milk contains several immunomodulator components which are important during infant period when the newborn's immune system is still under development. In this study, we aim at examining levels of cytokines, zinc (Zn), and copper (Cu) in milk from mothers of premature and mature infants, and comparing changes during lactation periods consequently. Milk was collected from total of 40 mothers (group M: mothers of mature infants, n = 20; group PM: mothers of premature infants, n = 20) from four lactation stages: colostrum (0–7 days), transitional (7–14 days), mature milk (21 days), and mature milk (2nd month). Levels of cytokines (interleukin [IL]-lβ, IL-2, IL-6, IL-8, tumor necrosis factor-alpha [TNF-α]) were determined by chemiluminesence method, whereas atomic absorption spectrophotometer was used for the determination of Zn and Cu levels. Cytokine levels were determined to be high in colostrum and transient milk from mothers of full-term infants, whereas their levels were reduced drastically in the 21st day and the 2nd month milk (P < .01 , P < .001). Similar trends were observed in milk from mothers of premature infants, but cytokine levels were significantly lower in colostrum compared to colostrum from mothers of mature infants (P < .01). The differences in cytokine levels were continuous in transient milk (P < .05) and mature milk (21 days) (P < .05), whereas there was no statistically significant differences between milk from both groups of mothers in the 2nd month (P > .05). Zn levels in milk from mothers of premature infants were significantly lower compared to the ones from mothers of mature infants (P < .01) and these differences continued through the 2nd month. Although Cu levels were lower in milk from mothers of premature infants, there was no statistically significant difference except colostrum (P > .05). Our results clearly demonstrate that the level of immunomodulating agents such as cytokines and trace elements in milk from mothers of premature infants is less than the level of the same agents in milk from mothers of full-term infants. Although there are commercially available products for infant feeding, human milk is still the best natural nutrient for newborns. Therefore, when premature infants are breastfed, necessary precautions such as supplemantary diets must be considered for possible infections and risks related with immune system deficiency.

Analysis of Bacillus anthracis Spores in Milk Using Mass Spectrometry

New approaches for identifying biological threat agents in raw milk using spectroscopy were tested using Bacillus anthracis (BA) Sterne strain spores seeded into unpasteurized bulk tank milk. Direct filtration onto Tyvek membranes provided the optimal filtration approach from raw milk, but detection limits were not ideal. When beads coated with anti-BA antibodies were mixed with spores in raw milk, the beads were capable of concentrating the spores that could be later detected and characterized by MALDI spectroscopy based on presence of previously characterized small acid-soluble proteins (SASP's). This approach could provide a very rapid assessment of whether milk or milk products have been purposefully contaminated with BA spores. This work was fundamentally a proof-of-concept study demonstrating feasibility of the approach in milk. Other parameters could be changed to potentially lower detection limits, and additional studies are currently underway to improve the approach.

Structure and functional performance of gigartinacean kappa–iota hybrid carrageenan and solieriacean kappa–iota carrageenan blends

Hybrids of kappa and iota carrageenans, known as kappa-2 carrageenans, of contrasting phycological origin and type of hybridization were compared chemically and functionally. Nuclear magnetic resonance spectrometry showed gigartinacean kappa-2 (hybridization was known to be a co-occurrence of kappa and iota structures in a chain) to contain 45% iota and 55% kappa, very similar to a 3:3 kappa:iota hand-made blend of solieriacean origin (hybridization was that kappa and iota occurring as separate chains). Gel permeation chromatographic data, however, demonstrated the gigartinacean extract to possess lower molecular weight compared to the solieriacean extracts, a hint to the variability in the origin of the two hybrid carrageenans. As texturing agents in water and milk systems, gigartinacean kappa-2 was found to produce inferior gels compared to its hand-made counterpart. However, both hybrids were found to exhibit similar functional performance as viscosity-enhancing/stabilizing agent in hot-processed chocolate milk preparations, and analogous inutility as viscosity build-up agent in cold-processed chocolate milk. A hand-made solieriacean kappa–iota blend can have the same properties as a gigartinacean kappa-2, but it depends on the actual application which blend performs comparable to kappa-2.

Milk antimicrobial residues in Holstein dairy cattle treated for toxic puerperal metritis

The objective of this study was to determine the presence of antimicrobial agents in milk and the time milk from cows treated for toxic puerperal metritis remained positive for antimicrobial residues. 51 Holstein dairy cows were divided into 3 treatment groups: Group 1 was treated with penicillin; Group 2 was treated with penicillin and tetracycline; and Group 3 was treated with ceftiofur sodium. Cows in Groups 1 and 2 received a daily intramuscular injection of procaine penicillin G at the standard farm-wide dose of 18 million units for 5 consecutive days, nearly 4 times the recommended dose of 3000 U/lb (6600 U/kg). In addition, cows in Group 2 were infused with 6 g of oxytetracycline diluted in 75 ml of sterile water on days 1, 3, and 5. Cows in Group 3 received a daily intramuscular injection of ceftiofur sodium at a standard farm-wide dose of 1 g for 5 consecutive days. Milk samples were collected on day 1, before the first dose of antimicrobial agent was administered, and on days 6 through 12 after the final day of treatment with antimicrobial agents. LacTek B-L (beta-lactam), LacTek TC (tetracycline), and LacTek CEF (ceftiofur) test kits were used to determine penicillin, tetracycline, and ceftiofur sodium residues, respectively, in milk samples. All 3 test kits used in this study have been phased out of production and are no longer available. Milk from 9 of 17 cows treated with penicillin was positive for beta-lactam residues for an average of 3.44 days post-treatment. In a separate group, 6 of 17 cows treated with penicillin were positive for beta-lactam residues for an average of 3.66 days post-treatment. Nine of 17 cows treated with oxytetracycline were positive for tetracycline residues for an average of 1.22 days following treatment. No milk residues were detected in cows treated with ceftiofur sodium. Antimicrobial residues were found in milk from cows treated with penicillin and oxytetracycline for 1 to 7 and 0 to 3 days, respectively, from the last day of treatment. In this study, milk from cows treated with penicillin tested positive for residues longer than expected and longer than the labelled withholding time. Antimicrobial screening may be necessary to prevent food contamination.

Global perspectives in breast milk contamination: infectious and toxic hazards.

Breast milk is the natural and optimal food for infants. In addition to meeting nutritional needs, breast milk provides numerous immunologic, developmental, psychologic, economic, and practical advantages. It is postulated that breast-feeding may also be related to the prevention of some adult health problems such as diabetes and coronary heart disease. Malnutrition among infants and young children, which remains one of the most severe global public health problems, is among the main reasons that the World Health Organization (WHO) so strongly supports breast-feeding. However, WHO recognizes the growing concern expressed by scientists, health professionals, environmentalists, and mothers about the potential risks posed by the presence of toxicants and infectious agents in breast milk. In this paper we review the main infectious hazards (tuberculosis, hepatitis B, and human immunodeficiency virus) and selected chemical hazards (tobacco, persistent contaminants) and the activities undertaken by WHO. We conclude that in cases where there is a high degree of pollution from chemical sources occurring simultaneously in a bacterially contaminated environment, the choice is not simply between polluted breast milk and risk-free substitutes. Rather, informed choice is based on assessing the known and unknown risks of artificial feeding versus the unknown, but potential, risks of chemical contamination of breast milk. Clearly, the possible toxicity of compounds requires further investigation. Of much greater importance, however, are effective measures to protect the environment for the entire population by controlling the use of these toxic products. Current scientific evidence does not support altering WHO's global public health recommendation of exclusive breast-feeding for 6 months followed by safe and appropriate complementary foods, with continued breast-feeding, up to 2 years of age or beyond.

Evolution of the mammary gland defense system and the ontogeny of the immune system.

A decisive event in the evolution of mammals from synapsid reptiles was the modification of ventral thoracic-abdominal epidermal glands to form the mammary gland. The natural selection events that drove the process may have been the provision of certain immunological agents in dermal secretions of those nascent mammals. This is mirrored by similar innate immune factors in mammalian sebum and in protherian and eutherian milks. On the basis of studies of existing mammalian orders, it is evident that immune agents in milk such as immunoglobulins, iron-binding proteins, lysozyme, oligosaccharides, and leukocytes compensate for developmental delays in early postnatal production of antimicrobial factors. At least in human milk, anti-inflammatory and immunomodulating agents also evolved to provide different types of protection for the offspring. In addition, investigations reveal that the types or concentrations of immunological agents in milk vary depending upon the type of placenta, lactation pattern, and environment of the species.