Staphylococcus aureus in cow milk and milk products in Ambo and Bako towns, Oromia, Ethiopia: prevalence, associated risk factors, hygienic quality, and antibiogram / Staphylococcus aureus en leche de vaca y productos lácteos en las ciudades de Ambo y Bako, Oromia, Etiopía: prevalencia, factores de riesgo asociados, calidad higiénica y antibiograma

Background: Staphylococcus aureus (S. aureus) is a foodborne bacterial pathogens that can cause staphylococcal food poisoning and contaminate food of animal origin worldwide. The current study was conducted to estimate the prevalence and assess risk factors, hygienic quality, and antibiogram of S. aureus in raw milk and milk products of cows in Ambo and Bako towns, Ethiopia. Results: The overall prevalence of S. aureus in milk and milk products was 15.6% (94/601) with the highest prevalence in bulk tank raw milk (17.50%) and the lowest in “Ergo” (13.11%). High S. aureus contamination at farm level were associated with poor farm hygiene, extensive management system, medium farm size, loose housing, and less frequent removal of bedding. At the cow level, a high S. aureus isolation rate was observed in crossbred cows; cows with age equal to or greater than 5 years old, tick infestation, history of mastitis treatment, and udder washing were not practiced before milking. On the other hand, the type of container, hygiene of milk handler, and container were the major risk factors for bulk tank milk contamination with S. aureus. S. aureus counts ranging from 1.25 × 104 to 1.92 × 104 CFU/mL were detected in 28.33% of the bulk tank milk samples.. Antimicrobial susceptibility test showed higher resistance of S. aureus to amoxicillin (98.48%), oxacillin (98.48%), ampicillin (98.48%), cefoxitin (92.42%), and tetracycline (83.33%), with 43.94% of isolates showing multidrug resistance (MDR). The high prevalence of oxacillin and cefoxitin-resistant isolates, which is a possible indicator of the existence of methicillin-resistant Staphylococcus aureus (MRSA), was also noted in the current study...(AU)

Toxicological evaluations of colostrum ultrafiltrate.

Colostrum has been consumed safely for many years as a food collected directly from cows. More recently, an ultrafiltrated bovine colostrum product has been developed; however, its safety in toxicology studies has not been extensively evaluated. To assess the safety of bovine colostrum ultrafiltrate, in accordance with internationally accepted standards, the genotoxic potential was investigated in a bacterial reverse mutation test, an in vitro chromosomal aberration test, and an in vivo mammalian micronucleus test. No mutagenicity or genotoxic activity was observed in these three tests. A 90-day repeated-dose oral toxicity study in Hsd.Han Wistar rats was conducted at doses of 0, 1050, 2100, and 4200 mg/kg bw/day by gavage. After 90 days of continuous exposure, no mortality or treatment-related adverse effects were observed, and no target organs were identified. The no-observed-adverse-effect level (NOAEL) was determined to be 4200 mg/kg bw/day, the highest dose tested.

Industrial milk powder in bioassays for evaluation of cytotoxicity and genotoxicity / Leites industrializados, tipo em pó, frente a bioensaios de avaliação de citotoxicidade e genotoxicidade

Considering the widespread consumption of milk powder by the general population as well as the lack of studies on the toxicity of such industrialized foods, this study evaluated the cytotoxic and genotoxic potential of powdered milk from four reputed companies in the food market of Brazil and other South American countries. Milk samples were evaluated in root meristem cells of Allium cepa L., at concentrations of 0.065 and 0.13 g/mL, for 24 and 48 hours of exposure; and by means of cell viability in culture of cells of normal lineage, via MTT test, for 24 hours, at concentrations of 0.016; 0.032; 0.065 and 0.13g/mL. The concentration 0.13 g/mL was the one suggested for consumption in all milk packages evaluated in this study. In A. cepa, we observed that the milks, at both concentrations and at the two exposure times investigated, reduced the cellular proliferation of root meristems demonstrating a significant cytotoxicity. Furthermore, 0.13g/mL milks at the exposure time of 24h induced an expressive frequency of cellular alterations in the plant tissue, showing to be genotoxic. In the in vitro evaluation, three milks at 0.065 g/mL and all milks at 0.13 g/mL have significantly reduced cell viability, proving to be cytotoxic to the analyzed cell culture. Therefore, under the studied conditions, the powdered milks evaluated caused significant genetic instability to the cells of the test systems used.

Devido o amplo consumo de leite em pó pela população em geral, bem como, a carência de estudos sobre a toxicidade de tais alimentos industrializados, objetivou-se na presente pesquisa avaliar o potencial citotóxico e genotóxico de leites em pó provenientes de quatro empresas de reconhecida atuação no mercado de alimentos brasileiro e de outros países da América do sul. As amostras de leite foram avaliadas em células meristemáticas de raízes de Allium cepa L., nas concentrações 0,065 e 0,13g/mL, por 24 e 48 horas de exposição; e por meio da viabilidade celular em cultura de células de linhagem normal, via teste MTT, por 24 horas, nas concentrações 0,016; 0,032; 0,065 e 0,13g/mL. A concentração 0,13 mL/kg foi a sugerida para consumo em todas embalagens de leites avaliados neste estudo. Em A. cepa, verificou-se que os leites, nas duas concentrações e nos dois tempos de análise considerados, reduziram a proliferação celular dos meristemas de raízes demonstrando citotoxicidade significativa. Ainda, os leites na concentração 0,13g/mL induziram, no tempo de exposição 24h, frequência expressiva de alterações celulares ao tecido vegetal, mostrando-se genotóxicas. Na avaliação in vitro, três leites na concentração 0,065g/mL e todos na concentração 0,13g/mL reduziram significativamente a viabilidade celular mostrando-se citotóxicos a cultura de células analisada. Portanto, nas condições de estudo estabelecidas, os leites em pó avaliados causaram significativa instabilidade genética as células dos sistemas testes utilizados.

Effect of High-Calcium Diet on Coronary Artery Disease in Ossabaw Miniature Swine With Metabolic Syndrome.

BACKGROUND: Calcium is a shortfall essential nutrient that has been a mainstay of osteoporosis management. Recent and limited findings have prompted concern about the contribution of calcium supplementation to cardiovascular risk. A proposed mechanism is through the acceleration of coronary artery calcification. Determining causality between calcium intake and coronary artery calcification has been hindered by a lack of sensitive methodology to monitor early vascular calcium accumulation. The primary study aim was to assess the impact of high calcium intake on coronary artery calcification using innovative calcium tracer kinetic modeling in Ossabaw swine with diet-induced metabolic syndrome. Secondary end points (in vitro wire myography, histopathology, intravascular ultrasound) assessed coronary disease. METHODS AND RESULTS: Pigs (n=24; aged ≈15 months) were fed an atherogenic diet with adequate calcium (0.33% by weight) or high calcium (1.90% from calcium carbonate or dairy) for 6 months. Following 5 months of feeding, all pigs were dosed intravenously with (41)Ca, a rare isotope that can be measured in serum and tissues at a sensitivity of 10(-18) mol/L by accelerator mass spectrometry. Kinetic modeling evaluated early coronary artery calcification using (41)Ca values measured in serial blood samples (collected over 27 days) and coronary artery samples obtained at sacrifice. Serum disappearance of (41)Ca and total coronary artery (41)Ca accumulation did not differ among groups. Secondary end points demonstrated no treatment differences in coronary artery disease or function. CONCLUSION: There was no detectable effect of high calcium diets (from dairy or calcium carbonate) on coronary artery calcium deposition in metabolic syndrome swine.

Novel in vitro systems for prediction of veterinary drug residues in ovine milk and dairy products.

A new in vitro tool was developed for the identification of veterinary substrates of the main drug transporter in the mammary gland. These drugs have a much higher chance of being concentrated into ovine milk and thus should be detectable in dairy products. Complementarily, a cell model for the identification of compounds that can inhibit the secretion of drugs into ovine milk, and thus reduce milk residues, was also generated. The ATP-binding cassette transporter G2 (ABCG2) is responsible for the concentration of its substrates into milk. The need to predict potential drug residues in ruminant milk has prompted the development of in vitro cell models over-expressing ABCG2 for these species to detect veterinary drugs that interact with this transporter. Using these models, several substrates for bovine and caprine ABCG2 have been found, and differences in activity between species have been reported. However, despite being of great toxicological relevance, no suitable in vitro model to predict substrates of ovine ABCG2 was available. New MDCKII and MEF3.8 cell models over-expressing ovine ABCG2 were generated for the identification of substrates and inhibitors of ovine ABCG2. Five widely used veterinary antibiotics (marbofloxacin, orbifloxacin, sarafloxacin, danofloxacin and difloxacin) were discovered as new substrates of ovine ABCG2. These results were confirmed for the bovine transporter and its Y581S variant using previously generated cell models. In addition, the avermectin doramectin was described as a new inhibitor of ruminant ABCG2. This new rapid assay to identify veterinary drugs that can be concentrated into ovine milk will potentially improve detection and monitoring of veterinary drug residues in ovine milk and dairy products.

[Study on sub-chronic toxicity of powered milk containing transgenic human alpha-lactalbumin].

OBJECTIVE: To investigate the potential toxic or adverse effect of transgenic human alpha-lactalbumin powered milk on rats. METHODS: Weanling Wistar rats were randomly divided into seven groups according the weight: three transgenic milk powder (T) groups, three non-transgenic milk powder (N) groups and the control (C) group. The diets of T groups contain 15%, 30% and 60% transgenic human alpha-lactalbumin milk powder. The diets of N groups contain 15%, 30% and 60% non-transgenic human alpha-lactalbumin milk powder for 90 days. The diet of C group contains only basic feed. Haematological and biochemical parameters was measured during the study (at 45th and 90th of the experiment). At the end of the 90th day, organ tissues analysis was performed. RESULTS: There were no transgenic human alpha-lactalbumin related adverse effects on the body weight, food intake, food consumption, hematology,serum biochemistry, as well as histopathology. CONCLUSION: There were no signs of toxic and adverse effects for transgenic human alpha-lactalbumin powdered milk on rats.

Dietary patterns among the Metro Atlanta Cohort: implications for population-based longitudinal dietary pesticide exposure and risk assessment.

Characterizing dietary consumption patterns is critical to dietary pesticide exposure assessment. We compared consumption patterns between adults (age 18-60) in the Metro Atlanta Cohort (MAC), a longitudinal study of pesticide exposure among Atlanta residents, and US National Health and Nutrition Examination Survey (NHANES) adults. We focused on foods commonly eaten by US adults and foods likely to contain certain pesticide residues. MAC participants provided consumption data for 6 days per month for 1 year using a web-based data collection tool. We defined "percent eaters" as the percent of participants who reported eating a particular food in 24 h. We computed the NHANES weighted percent eaters and 95% confidence limits (CLs) using the 24-h dietary recall data. We calculated the MAC percent eaters for each sampling day and the percent of days this number fell below, within, or above the NHANES 95% CLs. We also re-sampled the MAC percent eaters across sampling days to find whether the resulting distribution resembled the NHANES estimate, and used the Kruskal-Wallis test to evaluate whether season affected the number of MAC eaters of a particular food on a given sampling day. In general, across all sampling days, a greater proportion of MAC participants reported eating banana, broccoli, cream, grapes, lettuce, onion, peach, pear, peas, strawberries, string beans, and tomatoes than the national estimate, whereas the proportion of apple, spinach, ketchup and white bread/roll eaters was similar, and the proportion of milk drinkers was lower. Season predicted the number of MAC peach and strawberry eaters but not other foods. The data show how a higher proportion of Atlanta adults may eat certain foods (e.g., peaches in summer or strawberries in spring) than the national average depending on season or other factors. An exposure assessment that ignored this difference could underestimate dietary pesticide intakes.

Surveillance of dioxins and polychlorinated biphenyls (PCBs) in food commercialized in Barcelona, Spain.

This study explored the potential use of seven congeners of polychlorinated biphenyls (PCBs-7) as indicator compounds for the presence of dioxins and PCBs in food samples, as part of the routine surveillance programme of a public health agency. Samples of 24 foodstuffs with high fat content were collected (ten fresh fish, six dairy products, five meat and three eggs). Duplicate analyses were performed. A research laboratory tested samples for seven polychlorinated dibenzo-p-dioxin (PCDDs), ten dibenzofurans (PCDFs) and twelve dioxin-like PCBs, with limits of detection in the range of ng kg(-1) (ppt). The public health services official control laboratory tested samples for PCBs-7, with a limit of quantification of 5 µg kg(-1) (ppb). The research laboratory detected the presence of dioxins and dioxin-like PCBs in all samples; fish samples had the highest levels (0.04-10.3 pg WHO-TEQ g(-1)). The public health service official control laboratory detected PCBs-7 only in five samples, which were all fish. Comparing the results in the two laboratories there seems to be an association between the detection of PCB-7 and the presence of higher levels of PCDD/Fs and dioxin-like PCBs. The use of PCB-7 as an indicator compound may be a practical surveillance strategy for those foodstuffs with higher concentrations of dioxin-like congeners.

Preclinical drug metabolism programs for food-producing animals.

To register a new veterinary drug for use in food-producing animals, the sponsor must demonstrate that drug-related residues in the edible tissues (liver, kidneys, muscle, fat, and milk or eggs) of treated animals are safe when consumed by humans. The sponsor must develop information on the amount, persistence, and chemical nature of the drug-derived residue in the edible tissues in order to ensure safety. This information is compared to that on the metabolism and toxicity of the compound in the laboratory animal species used for the toxicity evaluation. The toxicity data is utilized to establish the safe concentration of drug-related residue in the edible tissues. An estimate of the safe concentration is necessary to proceed with residue studies that will adequately determine the rate of depletion of total residue over the projected range of probable safe concentrations. Appropriate study design requires close communication among the toxicologist, pathologist, and residue chemist. The safe concentration of total residue and residue depletion profile are used to determine the withdrawal period for the veterinary product. The required studies, including design and timing, will be discussed.

[The effect of fermented hydrolyzed whey enriched with lactates on the morphological structure of the internal organs in laboratory animals]. / Vliianie fermentativno-gidrolizovannoi molochnoi syvorotki, obogashchennoi laktatami, na morfologicheskuiu strukturu vnutrennikh organov laboratornykh zhivotnykh.

Results of pathomorphological investigation of rat organs fed during 1 and 3 months the diet containing 8% of protein as milk whey protein partly hydrolysed by enzymes and enriched by lactates (SGOL-1) are presented. The conducted investigation have not revealed of pathological effect of a product SGOL-1 on morphological structures of investigated internal bodies and tissues of the laboratory animals. A increase of body mass of animals and contents of RNAS in cells of practically all bodies and tissues of the animals were also marked.

[Nitrates in cow's milk and in various milk products in the Ukraine]. / Nitraty v korov'em moloke i nekotorykh molochnykh produktakh USSR.

The results of the investigations conducted have shown that most milk samples analyzed contained from 2 to 55.2 mg/l nitrates (P50 = 27.2 mg/l), dried milk and dry milk mixtures contained from 56.5 to 91.0 mg/kg nitrates (P50 = 72.9 mg/kg). The amount of nitrates detected in most products prepared at special milk centers for child nutrition did not exceed the mean level of nitrates in the whole milk. However, 12% of milk samples and 6% of dry milk mixtures contained significantly higher levels of nitrates. A conclusion has been made on the necessity of testing and regulation of nitrate content in the milk and milk products for child nutrition.

Mutagenicity of the products obtained from heated milk systems.

Methylene chloride extracts of the browning reaction products prepared from model systems consisting of major milk components (casein and/or lactose, and non-fat dried milk) were tested for mutagenicity in the Ames Salmonella/microsome assay. Samples obtained by heating aqueous solutions of these components under either neutral or basic (pH 10) conditions exhibited no significant mutagenic activity when tested with or without S-9 mix. The addition of common food additives, such as sodium nitrite, butylated hydroxyanisole and butylated hydroxytoluene, to the aqueous solutions did not enhance the mutagenic activity of the browning samples. On the other hand, the tar samples prepared by heating the same milk components in the dry state exhibited strong mutagenicity, primarily to Salmonella typhimurium strain TA98 and only with S-9 mix. A casein/lactose mixture and non-fat dried milk were also heated with baking soda in the dry state. The presence of the baking soda enhanced the mutagenicity of the browning products; the tar from the non-fat dried milk heated with baking soda was the most potently mutagenic of all the samples towards strain TA98 and also produced a positive response in strain TA100 in the presence of S-9 mix.

Breast-milk monitoring to measure Michigan's contamination with polybrominated biphenyls.

In 1973 and 1974, several thousand Michigan dairy farms were contaminated by polybrominated biphenyls (P.B.B.) as the result of an industrial accident. An unknown quantity of contaminated meat and dairy products entered the food chain before contaminated farms were quarantined. To determine the extent of human exposure, P.B.B. concentrations were measured in human breast milk, which was collected in a random-sample survey from nursing mothers throughout Michigan. 96% of 53 samples from Michigan's lower peninsula and 43% of 42 samples from the less densely populated upper peninsula contained detectable levels of P.B.B. These data indicate that about 8 million of Michigan's 9.1 million residents have detectable body burdens of P.B.B.