Occurrence In Milk Research Articles

Stochastic health risk assessment of aflatoxin M1 in cow's milk among Lebanese population

This study quantitatively assessed AFM1 exposure through consumption of cows' milk in Lebanese adolescents and adults. Lebanon-specific, non-aggregated data on (i) milk intake and body weight – from an existing survey for adults and from a new survey for adolescents, and (ii) AFM1 occurrence in milk, were fitted to distributions and incorporated into a probabilistic model. Risk of hepatocellular carcinoma (HCC) for milk consumers was estimated considering the incidence of hepatitis B virus in Lebanon and characterized using the margin of exposure (MOE). All subgroups’ mean risk estimates, expressed as additional HCC cases per 100 000 population per year, were significantly different (p < 0.05), and ranged from 2.2x10−4 for adult males to 4.9x10−4 for adolescent males. This variation is attributed to significant differences in body weight and milk intake. MOE identified adolescent males and females as at-risk populations (mean 9628 and 8108, respectively). For adults, levels of concern were only reached with extreme consumption and/or contamination events. Considering that exposure from other sources (e.g., dairy) is cumulative, control of AFM1 in milk in Lebanon should be a risk management priority to ensure protection of younger populations.

Quantitative risk ranking of mycotoxins in milk under climate change scenarios

Mycotoxins are toxic fungal metabolites that may occur in crops. Mycotoxins may carry-over into bovine milk if bovines ingest mycotoxin-contaminated feed. Due to climate change, there may be a potential increase in the prevalence and concentration of mycotoxins in crops. However, the toxicity to humans and the carry-over rate of mycotoxins from feed to milk from bovines varies considerably. This research aimed to rank emerging and existing mycotoxins under different climate change scenarios based on their occurrence in milk and their toxicity to humans. The quantitative risk ranking took a probabilistic approach, using Monte-Carlo simulation to take account of input uncertainties and variabilities. Mycotoxins were ranked based on their hazard quotient, calculated using estimated daily intake and tolerable daily intake values. Four climate change scenarios were assessed, including an Irish baseline model in addition to best-case, worst-case, and most likely scenarios, corresponding to equivalent Intergovernmental Panel on Climate Change (IPCC) scenarios. This research prioritised aflatoxin B1, zearalenone, and T-2 and HT-2 toxin as potential human health hazards for adults and children compared to other mycotoxins under all scenarios. Relatively lower risks were found to be associated with mycophenolic acid, enniatins, and deoxynivalenol. Overall, the carry-over rate of mycotoxins, the milk consumption, and the concentration of mycotoxins in silage, maize, and wheat were found to be the most sensitive parameters (positively correlated) of this probabilistic model. Though climate change may impact mycotoxin prevalence and concentration in crops, the carry-over rate notably affects the final concentration of mycotoxin in milk to a greater extent. The results obtained in this study facilitate the identification of risk reduction measures to limit mycotoxin contamination of dairy products, considering potential climate change influences.

Mycotoxin Occurrence in Milk and Durum Wheat Samples from Tunisia Using Dispersive Liquid-Liquid Microextraction and Liquid Chromatography with Fluorescence Detection.

Food and feed contamination with mycotoxins is a major public health concern. Humans and animals are exposed to these toxins by consuming contaminated products throughout their lives. In this study, a method based on dispersive liquid-liquid microextraction (DLLME), followed by liquid chromatography with fluorescence detection (LC-FLD), was validated for the determination of aflatoxins (AFs) M1, B1, B2, G1, G2, zearalenone (ZEN), and ochratoxin A (OTA). The method was applied to 150 raw cow milk samples and 90 market durum wheat samples from two Tunisian climatic regions: the littoral region (Mahdia) and the continental region (Béja). This work was carried out to obtain more surveillance data to support rapid initiatives to assure safe foods and protect consumer health and to estimate the daily exposure of the Tunisian population consuming those products. AFG2 and OTA were found in wheat with incidences of 54.4 and 11.1%, respectively. On the other side, milk samples were contaminated by AFG2, AFB1, and AFB2 with incidences of 8.7%, 2.0%, and 0.67%, respectively. Some of the samples showed OTA concentrations above the maximum limit allowed by the European Union, which represents a health risk for consumers in Tunisia, where no legislation exists about the maximum content of mycotoxins in food.

“Vegan” and “plant-based” claims: risk implications for milk- and egg-allergic consumers in Canada

The market share of foods carrying labels suggesting absence of animal ingredients has significantly increased in recent years. The purpose of this study was to document the purchasing behaviour of egg- or milk-allergic consumers vis-à-vis food marketed as “vegan” and “plant-based”, and to evaluate the associated allergenic risk. A survey was conducted among egg- and milk-allergic consumers and revealed that 86% (margin of error 5.4%; confidence level 95%) would buy “vegan” products, indicating this label may be perceived as a substitute for “free from milk and eggs”. To assess the risk posed by these products, 87 prepackaged foods with “vegan” and/or “plant-based” claims purchased in Quebec were tested for milk proteins, and 64 for egg proteins. Overall, 5.7% and 0% occurrence of milk and egg proteins, respectively, were observed, suggesting that the analysed prepackaged foods carrying “vegan” and/or “plant-based” labels pose little risk to egg- or milk-allergic consumers. However, this is likely due to allergen management practices applied by the Canadian manufacturers of the products tested, and should not be attributed to the use of “vegan” or similar labels. Enhanced regulatory requirements for the use of these labels, and an education campaign on their meaning with respect to allergy-related risks, are necessary to better inform and protect egg- and milk-allergic consumers.

Phenotypic and genetic characterization of the occurrence of noncoagulating milk in dairy sheep

Milk coagulation ability is of central importance for the sheep dairy industry because almost all sheep milk is destined for cheese processing. The occurrence of milk with impaired coagulation properties is an obstacle to cheese processing and, in turn, to the profitability of the dairy companies. In this work, we investigated the causes of noncoagulation of sheep milk; specifically, we studied the effect of milk physicochemical properties on milk coagulation status [coagulating and noncoagulating (NC) milk samples, which do or do not coagulate within 30 min, respectively], and whether mid-infrared spectroscopy (MIR) could be used to assess variability in coagulation status. We also investigated the genetic background of milk coagulation ability. Individual milk samples were collected from 996 Sarda ewes farmed in 47 flocks located in Sardinia (Italy). Considered traits were daily milk yield, milk composition traits, and milk coagulation properties (rennet coagulation time, curd firming time, and curd firmness), and MIR spectra were acquired. About 9% of samples did not coagulate within 30 min. A logistic regression approach was used to test the effect of milk-related traits on milk coagulation status. A principal component (PC) analysis was carried out on the milk MIR spectra, and PC scores were then used as covariates in a logistic regression model to assess their relationship with milk coagulation status. Results of the present work demonstrated that the probability of having NC samples increases as milk contents of proteins and chlorides and somatic cell score increase. The analysis of PC extracted from milk spectra that influenced coagulation status highlighted key regions associated with lactose and protein concentrations, and others not associated with routinely collected milk composition traits. These results suggest that the occurrence of NC is mostly related to damage of the epithelium secretory mammary cells, which occurs with the advancement of a lactation or due to unhealthy mammary gland status. Genetic analysis of milk coagulation status and of the extracted PC confirmed the genetic background of the milk coagulability of sheep milk.

Influence of grains postharvest conditions on mycotoxins occurrence in milk and dairy products

Abstract Mycotoxins are secondary metabolites produced by some filamentous fungi, which can cause toxic effects in humans and animals. The purpose of the study was to report the influence of postharvest conditions of grains and animal feed on the occurrence of mycotoxins in milk and dairy products which are widely consumed worldwide and have several health benefits for consumers. Among the most toxic mycotoxins are aflatoxins (AFs), with AFB1 being the most toxic and present in grains and cereals used in the feeding of dairy cows. After ingestion, AFB1 is converted to AFM1, which is excreted in milk, being a source of direct contamination to consumers of this product and dairy products. Thus, knowledge about this substance and the care that can be taken to reduce the consumption of contaminated food is a matter of great importance concerning public health and food safety. This review reports that the temperature and humidity at which the grains are stored, are the main conditions that can be controlled during storage, aiming to reduce the growth of fungi and the production of mycotoxins. This work reinforces that the continuous control of mycotoxins in milk and dairy products is of vital importance to obtain a safe product. Besides, strategies to mitigate the development of fungal contamination have been carefully revised to prevent the formation of these toxic substances.

PSX-B-21 Diagnosis of early mastitis in dairy cows: Somatic cells and bacterial pathogen measuring

Abstract Mastitis is an inflammatory condition of the breast that can be caused by chemical, physical, traumatic injury or bacteria. In recent years, biomarkers for the mastitis diagnosis have been actively studied. The aim of the study was to assess the relationship between SCC and pathogenic bacteria in milk occurrence. The study carried out by milk samples collected in the experimental herd (Krasnodar region, Russia) from 85 Holsteinized Black-and-White cows. Healthy cows (HC; n = 4), cows at risk for clinical mastitis (RCM, n = 22), subclinical (SCM; n = 25) and clinical mastitis (CM; n = 34) groups were divided by a bacteriological cultivation and SCC level (Fossomatic7 DC). SCC results were logarithmically converted to SCS. Consequent groups were included animals with SCS level: HC (SCS &amp;lt; 4.1), RCM (4.2≤SCS≤5.3), SCM (5.4≤SCS≤6.3), CM (SCS &amp;gt;6.4). HC group of animals showed SCS equal to 3.11±0.28, 4.85±0.44 for RCM, 5.8±0.28 for SCM and 7.43±0.87 for CM. Identification of isolated bacteria species was carried out by conventional biochemical methods using the API20E, APIStaph, API20Strep tests (bioMerieux SA,France). Number of isolated pathogenic bacteria in CM group was 57 strains of which 33.3% were attributed to Enterobacteriaceae, 45.6% to coagulase-negative staphylococci (CONS), 12.3% to S.aureus and 8.8% to Ps.aeruginosa. In SCM group there were assigned 48 strains: 32.5% to Enterobacteriaceae strains, 42.5% to CONS, 20.0% to S.aureus, 5.0% to Ps.aeruginosa. The antibiotic susceptibility was determined according to NCCLS and EUCAST. S.aureus isolates showed the highest sensitivity to erythromycin (4.3% of resistant strains) and the highest resistance to ciprofloxacin (100%), tetracycline (95.0%), rifampicin (88.5%), benzylpenicillin (79.3%), novobiocin (69.2%) and fusidin (65.5%). The primary analysis of SCC and milk microbiological profile can be able to increase the accuracy of mastitis occurrence diagnosing that contributes to taking the right decision for choosing an antibiotic to preserve the cows’ health in Russian cattle population. The study was funded by RSF (project No.21-76-20046)

A Study of the Occurrence of Aflatoxin M1 in Milk Supply Chain over a Seven-Year Period (2014-2020): Human Exposure Assessment and Risk Characterization in the Population of Central Italy.

Aflatoxin food contamination represents a rising global issue that will continue to increase due to climate change. Aflatoxin M1 (AFM1) is of high concern for the whole dairy industry. In light of AFM1′s harmful potential, a human health exposure assessment and risk characterization were performed for all age populations of central Italy with regard to milk and cheese consumption by means of the margin of exposure (MOE). In total, 16,934 cow and ewe’s milk samples were collected from 2014 to 2020 and analyzed by an enzyme-linked immunosorbent assay (ELISA) screening method, confirmed by high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). The average concentration of AFM1 in cow’s milk ranged from 0.009 to 0.015 µg/kg, while in ewe’s milk, the average concentration ranged from 0.009 to 0.013 µg/kg. The average amount of AFM1 exposure ranged from 0.00005 to 0.00195 g/kg bw/day, with the main contributor represented by drinking milk, followed by the consumption of soft cheeses. A high level of public health concern related to the youngest consumers has arisen from risk characterizations highlighting the need for constant monitoring of AFM1′s occurrence in milk by inspection authorities, alongside regular updates with regard to exposure assessments.

Probabilistic risk assessment for milk in dark chocolate, cookies and other baked goods with PAL sold in Canada

The risk of having an allergic reaction in milk-allergic individuals consuming products with precautionary allergen labelling (PAL) for milk has been rarely studied in products such as dark chocolate, cookies, and other baked goods. A probabilistic risk assessment model was developed to estimate potential risks. Milk occurrence and contamination levels were reported in a previous article from our group. Dose-response curves for milk were constructed using values (n = 1078) from published double-blind placebo-controlled food challenges. Canadian consumption data was extracted from a national survey, and a homemade survey involving food-allergic Canadians. Milk eliciting doses (ED) were 0.23 (ED01), 1.34 (ED05), 3.42 (ED10), and 16.3 (ED25) mg of milk protein (Log-Normal distribution). Average exposures, per eating occasion, were 24 mg (dark chocolate), 3.9 mg (baked goods), and 0.20 mg (cookies) of milk proteins. The estimated risk of having a milk-induced allergic reaction by consuming foods with PAL for milk was higher for dark chocolate (16%; 15,881/100,000) than baked goods (3.8%; 3802/100,000) or cookies (0.6%; 646/100,000) in milk-allergic Canadians. Dark chocolate, cookies, and baked goods with PAL for milk, should be avoided by milk-allergic Canadians (consuming or not products with PAL) to prevent allergic reactions.

Aflatoxin M1 in Africa: Exposure Assessment, Regulations, and Prevention Strategies - A Review.

Aflatoxins are the most harmful mycotoxins causing health problems to human and animal. Many acute aflatoxin outbreaks have been reported in Africa, especially in Kenya and Tanzania. When ingested, aflatoxin B1 is converted by hydroxylation in the liver into aflatoxin M1, which is excreted in milk of dairy females and in urine of exposed populations. This review aims to highlight the AFM1 studies carried out in African regions (North Africa, East Africa, West Africa, Central Africa, and Southern Africa), particularly AFM1 occurrence in milk and dairy products, and in human biological fluids (breast milk, serum, and urine) of the populations exposed. Strategies for AFM1 detoxification will be considered, as well as AFM1 regulations as compared to the legislation adopted worldwide and the assessment of AFM1 exposure of some African populations. Egypt, Kenya, and Nigeria have the highest number of investigations on AFM1 in the continent. Indeed, some reports showed that 100% of the samples analyzed exceeded the EU regulations (50ng/kg), especially in Zimbabwe, Nigeria, Sudan, and Egypt. Furthermore, AFM1 levels up to 8,000, 6,999, 6,900, and 2040ng/kg have been reported in milk from Egypt, Kenya, Sudan, and Nigeria, respectively. Data on AFM1 occurrence in human biological fluids have also shown that exposure of African populations is mainly due to milk intake and breastfeeding, with 85-100% of children being exposed to high levels. Food fermentation in Africa has been tried for AFM1 detoxification strategies. Few African countries have set regulations for AFM1 in milk and derivatives, generally similar to those of the Codex alimentarius, the US or the EU standards.

&amp;lt;i&amp;gt;Aflatoxin&amp;lt;/i&amp;gt; M1 (&amp;lt;i&amp;gt;Aspergillus parasiticus, flavus&amp;lt;/i&amp;gt;) Occurrences in Milk and Milk Products and Its Possible Health Effects

Aflatoxin M1 (AFM1) occurrence in milk and milk products has been a major concern among food scientists over the past three decades owing to its possible health risk in humans. The well-documented AFM1 associated adverse health outcomes include hepatocarcinogens, mutagens genotoxins, mutagenicity, and teratogen. The paper reviews the occurrence of AFM1 in milk, milk products, and human milk in developing and developed countries, with its safety standards of regulation. The health associated risks with AFM1 are the important methods used in detecting and reducing AFM1 in milk and other milk products are presented.

Effect of yeast cell wall and (1→3)-β-d-glucan on transfer of aflatoxin from feed to milk in Saanen dairy goats

Aflatoxin B1 (AFB1) is a carcinogenic compound of global concern due to its occurrence in milk as aflatoxin M1 (AFM1). The aim of this study was to investigate the potential reduction of carryover of feed AFB1 to dairy goat milk by yeast cell wall (CW) and its (1→3)-β-d-glucan (βG). To this end, the CW was physically extracted and its βG was also extracted by a modified method. Twenty one Saanen dairy goats (44.2 ± 4.10 kg BW) were assigned to 3 groups receiving 25 μg AFB1/kg DMI (AFB1 group), AFB1 group + 5 g CW/d (AFB1 + CW) and AFB1 group + 3 g βG/d (AFB1 + βG) in a completely randomized design. After one week of adaptation, all goats experienced a mild-15-day-AFB1 challenge during which their performance, DMI, AFM1 carryover and blood parameters were evaluated. Initial and final BW, milk yield and milk composition, DMI and efficiency of feed intake were similar among different groups, while energy corrected milk (ECM)/DMI were higher in βG and CW fed goats (1.28 and 1.24, respectively) compared to AFB1 group (0.92, p = 0087). The AFB1 + βG group had significantly lower milk AFM1 concentration, milk AFM1 excretion, and carryover than AFB1 group. The carryover of milk AFM1 (%) in AFB1, AFB1 + CW and AFB1 + βG groups were 0.29, 0.20 and 0.09 respectively in 3rd day (p = 0.007) and 0.22, 0.11 and 0.6 respectively in 15th day (p = 0.01). The milk AFM1 content of AFB1 + CW group at 3rd day of experiment showed that CW failed to sequester AFB1 effectively, because milk AFM1 concentration, excretion, and carryover were similar to AFB1 group. The white blood cells (WBC), red blood cells (RBC), hemoglobin, hematocrit, total protein, aspartate transaminase (AST), alanine transaminase (ALT) and leukocyte count of different experimental groups were not significantly different. Overall, the results of this study indicated that βG had more AFB1 binding ability than CW and could reduce milk AFM1 concentration below the maximum permitted level of milk AFM1 set by European Commission without adverse effects on milk production and milk composition; therefore, it may be used as a potent AFB1 absorbent in livestock diet.

Effect of different microbial concentrations on binding of aflatoxin M1 and stability testing

Aflatoxin M1 (AFM1) is a group 2b category carcinogenic compound of global concern due to its occurrence in milk. Various microbes have been employed for the binding of AFM1 and to reduce its bioavailability in humans. In the current study three strains of lactic acid bacteria, a strain of Saccharomyces cerevisiae and a mixture of all four were used to evaluate their binding potentials for AFM1. Milk samples were spiked with two different concentrations of AFM1, 0.05 and 0.1 μg/l, and four concentrations of microbes, 107, 108, 109 and 1010 cfu/ml, were tested to evaluate their binding potentials. The concentration of AFM1 and microbes were found to significantly affect the binding potentials of microbes. Saccharomyces cerevisiae, Lactobacillus helveticus and the mixture of microbes at the concentration of 1010 cfu/ml resulted in 100% binding of AFM1. Lactobacillus helveticus was found to have a higher binding potential than any other lactic acid bacteria reported previously. The binding of AFM1 with microbes was reversible as the washing test resulted in ∼20–∼70% release of AFM1. These results indicate that the microbes can be effectively used for the reduction of AFM1 levels up to safe limits in milk and milk products.

Biofilm-producing ability of Staphylococcus aureus isolates from Brazilian dairy farms

This study aimed to investigate the in silico biofilm production ability of Staphylococcus aureus strains isolated from milking parlor environments on dairy farms from São Paulo, Brazil. The Staph. aureus isolates were obtained from 849 samples collected on dairy farms, as follows: milk from individual cows with subclinical mastitis or history of the disease (n=220); milk from bulk tank (n=120); surfaces of milking machines and utensils (n=389); and milk handlers (n=120). Thirty-one Staph. aureus isolates were obtained and categorized as pulsotypes by pulsed-field gel electrophoresis and submitted to assays for biofilm formation on polystyrene, stainless steel, rubber, and silicone surfaces. Fourteen (45.2%) pulsotypes were considered producers of biofilm on the polystyrene microplate assay, whereas 13 (41.9%) and 12 (38.7%) pulsotypes were biofilm producers on stainless steel and rubber, respectively. None of the pulsotypes evaluated produced biofilms on silicone. Approximately 45% of Staph. aureus pulsotypes isolated from different sources on dairy farms showed the ability to produce biofilms in at least one assay, indicating possible persistence of this pathogen in the milking environment. The potential involvement of Staph. aureus in subclinical mastitis cases and its occurrence in milk for human consumption emphasize the need to improve hygiene practices to prevent biofilm formation on the farms studied.

Aflatoxin M1 incidence in milk produced in two regional surveillance systems from Transylvania area.

Aspergillus , Penicillium and Fusarium species are the most frequent toxigenic fungi found in Europe which produce aflatoxin B1 transformed into M1 in milk. This toxin is highly dangerous for human health, being carcinogens, mutagens and also teratogens. The aim of this study was to evaluate the incidence of M1 aflatoxin in cattle growth units for milk production and also in collecting units found in two surveillance systems from Transylvania. This incidence was further compared among these systems so as to establish the prevalence area of aflatoxin M1 occurrence in milk. The material used was represented by 141 raw milk samples analyzed and tested in 2 regional sanitary veterinary control laboratories by immuno-enzymatic ELISA method. Of the total samples, 56 were obtained from milk collecting units and 85 from growth units. The study shows that in 35.65% of the samples analyzed the identification of aflatoxin M1 was possible. Surprisingly, in the growth units with less than 100 individuals, aflatoxin M1 was identified in a proportion of 81.4%. None of the samples with M1 toxin exceeded the limit of 0.05 µg/kg, which is the maximum allowed. In the samples gathered from collecting centers from both surveillance systems a percent of 48 were identified with M1 afllatoxin, and 2 samples showed values that exceeded the one stated by the current legislation. When comparing the two surveillance systems we found significant differences (p<0.05), one being with a much higher prevalence and with positive samples. In one of the supervised areas there is a potential contamination hazard with AFM1, while in the second one the probability of contamination through milk consumption is very low. As consequence we further recommend that in the problem surveillance system a careful monitoring of feedstuffs to be made in order to prevent its occurrence in milk.

Aflatoxin occurrence in milk and supplied concentrates of goat farms of north‐eastern Italy

AbstractBACKGROUND: There is little information about the occurrence of aflatoxin M1 in goat milk. A survey involving 17 dairy goat farms of north‐eastern Italy was completed during 2005 and 2006, in order to evaluate the prevalence of milk contamination and its relationship with type and level of concentrate supplied.RESULTS: 132 concentrate and 85 milk samples were collected during five farm visits and analysed for aflatoxins. Aflatoxin B1 (AFB1) was &gt; 0.1 µg kg−1 in two‐thirds of the feeds and &gt; 5 µg kg−1 in nine. Contamination was higher in maize than in other pure feeds (median: 0.8 versus 0.1 µg kg−1); complementary feeds showed intermediate values. Aflatoxin M1 (AFM1) was &gt; 3 ng kg−1 in one‐third of milks and &gt; 25 ng kg−1 in three. All the milk samples were below EU statutory limits. The farm ranks for milk AFM1 level and the peak of concentrate AFB1 contamination were significantly correlated (0.642).CONCLUSIONS: Risk to human health was generally found to be absent, with only a few cases involving feed contamination to be monitored. The main aflatoxin risk for goat milk could arise from maize and maize‐based concentrates in the more intensive breeding conditions. Copyright © 2008 Society of Chemical Industry

Volatile Sulphur Compounds in UHT Milk

Several volatile sulphur compounds have been detected in raw and processed milk. These are hydrogen sulphide, methanethiol, carbonyl sulphide, dimethyl sulphide, carbon disulphide, dimethyl disulphide, dimethyl trisulphide, dimethyl sulphoxide, and dimethyl sulphone. Many of these increase in milk during heat processing and are associated with the cooked flavor of heat-treated milks, particularly UHT and sterilized milk. Several researchers have attempted to explain the origin of these volatiles in both raw and processed milk, and how to reduce the associated cooked flavor that has a negative impact on consumer acceptability of processed milk. These compounds are difficult to detect and analyze due to their high volatility, sensitivity to oxidation and heat, and in some cases, their very low concentrations. However, methods of detection and quantification have improved in recent years. Pre-concentration methods such as solid phase microextraction (SPME) together with gas chromatography equipped with sulphur-selective detectors now enable low concentrations of these compounds to be analyzed. In this review, methods of extraction and analyzis of these volatile sulphur compounds are comared, and their occurrence in milk is reviewed.

Contamination of food by fluorinated surfactants – Distribution in emulsions and impact on the interfacial protein behaviour

Perfluorooctanesulphonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the final products of degradation of numerous fluorochemicals, intensively used in industry. Due to their high stability and low level of biodegradability, they remain in the environment. Their occurrence in milk constitutes one of the numerous initial steps of contamination of many manufactured food products. We contributed to the understanding of the food contamination in analysing the distribution of PFOS and PFOA in food model emulsions. Emulsions stabilised by whey protein isolates were prepared from either contaminated aqueous phase or contaminated sunflower seed oil phase and homogenised at high pressures. Aqueous and creamed phases of emulsions were separated to evaluate the distribution of PFOS and PFOA between these two phases using a combination of liquid chromatography and mass spectrometry. PFOS and PFOA, initially present in water, migrate in the creamed phase due to their bindings with proteins that cover the oil–water interface of oil droplets. PFOS may also be present at interfaces due to its hydrophobicity. PFOS and PFOA bound to proteins moreover modified the interfacial behaviour of proteins at model air–water interfaces in proportions depending on the concentration and the head group of the perfluorinated surfactants.

Aflatoxins occurrence in milk and feed in Northern Italy during 2004–2005

Aflatoxin B 1, a common occurring type of aflatoxin in feed, is a potent cancer-causing agent. Lactating cows fed with aflatoxin-contaminated feed trasmit the toxin, as the metabolic form aflatoxin M 1, into the milk with high risk for consumers. The aim of this study is to determine the contamination degree of raw milk and feed in Valle d’Aosta region. From the beginning of 2004 to the end of 2005 samples of raw cow’s milk and cattle feed has been analysed: in 2004, the presence of aflatoxin M1 in milk and B1 in feed was higher than the maximum allowable in 1.7% of raw milk samples and in 8.1% of feed samples. In 2005 the presence of these aflatoxins are below the limits of EU regulations. The samples were analysed with an ELISA immunoassay, used as screening test, and the positive samples were confirmed by the HPLC analysis.

Lactoperoxidase: physico-chemical properties, occurrence, mechanism of action and applications.

Lactoperoxidase (LP) is one of the most prominent enzymes in bovine milk and catalyses the inactivation of a wide range of micro-organisms in the lactoperoxidase system (LP-s). LP-systems are also identified as natural antimicrobial systems in human secretions such as saliva, tear-fluid and milk and are found to be harmless to mammalian cells. The detailed molecular structure of LP is identified and the major products generated by the LP-s and their antimicrobial action have been elucidated for the greater part. In this paper several aspects of bovine LP and LP-s are discussed, including physico-chemical properties, occurrence in milk and colostrum and mechanisms of action. Since the introduction of industrial processes for the isolation of LP from milk and whey the interest in this enzyme has increased considerably and attention will be paid to potential and actual applications of LP-systems as biopreservatives in food and other products.