Levels of dioxins and dioxin-like PCBs in food of animal origin in the Netherlands during the period 2001-2011

Comparison of Food Safety Hazards in Pigs and Broilers from Intensive and Extensive Production Systems: A Literature Review

Consumer demand for meat from extensive production (e.g., organic, free-range, and antimicrobial-free) is increasing, partly due to consumers' perception that these types are safer than conventional meats. This review compared food safety hazards (namely, zoonotic parasites, bacterial pathogens, antimicrobial resistance, and chemical hazards) from pigs and broilers raised in intensive and extensive systems in Northern and Western European countries and the United States. Our findings showed that hazard occurrence between livestock production systems varied depending on the hazard. Pigs and broilers from extensive systems showed a higher prevalence of Toxoplasma gondii. Pathogen prevalence in pigs did not appear to be affected by production systems, while no clear conclusion could be drawn for broilers due to conflicting findings. Higher antimicrobial resistance (AMR) prevalence was common in pig and broiler samples from intensive farming, although samples from extensive farming were not free of AMR either. Studies on chemical hazards were limited, showing generally low contaminant levels in both production systems, including persistent organic pollutants, heavy metals, mycotoxins, pesticide residues, and antimicrobial residues. Therefore, more studies on chemical hazards are recommended to fill this data gap. Various factors associated with specific production systems could influence hazard prevalence, e.g., indoor confinement, outdoor access, antimicrobial policy, and slaughtering age. Regardless of the production system, other factors, such as seasonal variation and biosecurity levels, were also important.

The resilience of the pork supply chain to a food safety outbreak: The case of dioxins

Food supply chains are constantly challenged by food safety hazards entering the chain. The ability of the supply chain to provide safe food within a reasonable time after such a food safety threat or shock can be investigated with the concept of resilience using food safety as an indicator. Resilience is then defined as the food safety performance deviation due to the shock and takes both the severity of the shock as well as the time to fully recover or reach a new equilibrium into account. This study developed a stochastic simulation model to evaluate the resilience of the Dutch pork supply chain to dioxin contamination in the feed. The resilience of the supply chain as well as the potential costs associated with the contamination are compared between several monitoring strategies with the aim to determine the optimal control points for dioxin monitoring. Model results show that collecting and analyzing samples at more than one control point along the pork supply chain, in particular at feed mills and fat melting facilities, resulted in the highest resilience and the lowest costs after a shock. This model and these results can be used by public and private decision makers to make proactive and informed decisions on the monitoring strategies to control dioxins in the pork supply chain that result in optimal resilience to a dioxin crises.

Dietary exposure levels to polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and non-ortho-polychlorinated biphenyls in US meat, poultry and siluriform fish from 2018 to 2019

Daily dietary exposure estimates from beef, pork, chicken, turkey and siluriform fish were calculated using toxic equivalency (TEQ) data from the U.S. Department of Agriculture's survey of dioxins and dioxin-like compounds (DLCs) in the domestic meat supply and consumption data. Exposure estimates for the whole population and age groups were based on mean consumption of a commodity and mean or 90th percentile TEQ dioxin levels from the survey. Ratios of the exposure estimates to the U.S. EPA oral reference dose (RfD) of 0.7 pg TEQ/kg bw/day were calculated to determine if domestic meat might contribute materially to consumer exposure. In general, normal consumption of lean beef, pork, chicken and turkey will not cause exposures exceeding the RfD. Non-lean meats will have higher dioxin levels as dioxins accumulate in fat, therefore consumption of non-lean meat might cause higher exposure than compared to lean meat. However, on a mean basis, none of the exposure estimates for non-lean beef, pork, chicken or turkey exceeded the RfD for any of the age groups. For some age groups, especially toddlers, there are commodities such as non-lean beef in the 90th percentile of dioxin TEQs and siluriform fish that might exceed the RfD on occasion.

Designing optimal food safety monitoring schemes using Bayesian network and integer programming: The case of monitoring dioxins and DL-PCBs

Efficient food safety monitoring should achieve optimal resource allocation. In this article, a methodology is presented to optimize the use of resources for food safety monitoring aimed at identifying noncompliant samples and estimating background level of hazards in food products. A Bayesian network (BN) model and an optimization model were combined in a single framework. The framework was applied to monitoring dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs) in primary animal-derived food products in the Netherlands. The BN model was built using a national dataset with monitoring results of dioxins and DL-PCBs in animal-derived food products over a 10-year period (2008-2017). These data were used to estimate the probability of detecting suspect samples with dioxins and DL-PCBs levels above preset thresholds, given certain sample conditions. The results of the BN model were then inserted into the optimization model to compute an optimal monitoring scheme. Model estimates showed that the probability of dioxins and DL-PCBs exceeding threshold limits was higher in laying hen eggs and sheep meat than in other animal-derived food (except deer meat). Compared with the monitoring scheme used in the Netherlands in 2018, the optimal monitoring scheme would save around 10,000 EUR per year. This could be obtained by reallocating monitoring resources from products with lower probability of dioxin and DL-PCBs exceeding threshold limits (e.g., pig meat) to products with higher probability (e.g., bovine animal meat), and by shifting sample collection from the last quarter of the year toward the first three quarters of the year.

The first German total diet study (BfR MEAL Study) confirms highest levels of dioxins and dioxin-like polychlorinated biphenyls in foods of animal origin

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Presentation of PCDD/F and dl-PCB data in 300 foods prepared as consumed in Germany.

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By wet weight, highest levels in fish products, fatty fish, sheep liver, and butter.

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By fat weight, highest levels in game, dairy products, and sheep meat.

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MEAL foods did not exceed EU maximum levels.

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Evaluation of the impact of regions and type of production.

The first German Total Diet Study, called the BfR MEAL Study, generated a comprehensive dataset of polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in foods representative for the consumption habits in households in Germany. PCDD/Fs and dl-PCBs are persistent organic pollutants. Dietary intake is considered to be the most relevant exposure pathway for humans. Levels were examined in 300 foods that were prepared as typically consumed by the population in Germany. Highest PCDD/F and dl-PCB levels were detected in animal-based foods such as fish, butter, dairy products, liver, and meat. The comparison of conventionally and organically produced foods revealed a trend to slightly higher contents in organically produced foods. Sampling discriminated by region and season showed no major differences. Analysed occurrence data will improve future dietary exposure and food safety assessments in Germany.

Presence and risks of polycyclic aromatic hydrocarbons, dioxins and dioxin-like PCBs in dietary plant supplements as elucidated by a combined DR CALUX® bioassay and GC-HRMS based approach

Plant-based dietary supplements may contain undesirable contaminants such as polycyclic aromatic hydrocarbons, dioxins and dioxin-like polychlorinated biphenyls (dl-PCBs) due to the sources of raw materials or processing methods used. The presence of these contaminants in a series of herbal supplements sold on the Ghanaian market for improving sexual performance was examined using the DR CALUX^® bioassay in combination with GC-HRMS analysis. Overall, cell responses at 4 and 48 h exposure to extracts prepared without an acid-silica clean-up were relatively higher than the responses obtained from extracts prepared with an acid-silica clean-up. This indicated that the 40 supplements contained only low levels of stable aryl hydrocarbon receptor (AhR) agonists like polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dl-PCBs, while some contained substantial amounts of less stable AhR-agonists. Ten supplements selected for confirmation with GC-HRMS analysis contained PCDD/Fs and dl-PCBs at levels ranging from 0.01 to 0.19 pg toxic equivalent (TEQ)/g only, while the level of the sum of 4 polycyclic aromatic hydrocarbons (Σ4PAHs) representing less stable AhR agonists, ranged from not detected (ND) to 25.5 ng/g. These concentrations were in line with the responses observed in the DR CALUX^® bioassay. The concentration of PCDD/Fs and dl-PCBs corresponded to estimated daily intakes (EDIs) ranging from 0.01 to 1.20 pg TEQ/day, or 0.001 to 0.12 pg TEQ/kg bw/week for a 70 kg bw consumer, which was below the established tolerable weekly intake (TWI) of 2 pg TEQ/kg bw/week, thus indicating low concern for consumers' health. Similarly, the EDIs based on the detected Σ4PAHs in supplements ranged from 7.2 to 111 ng/day, or 0.1 to 1.6 ng/kg bw/day, which corresponded to MOE values above 10,000, indicating a low health concern.

Survey of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and non-ortho-polychlorinated biphenyls in U.S. meat, poultry, and siluriform fish from 2018-2019: toxic equivalency levels, temporal trends, and implications

The U.S. Department of Agriculture (USDA) conducted a survey of domestic animal products including beef fat, pork fat, chicken fat, turkey fat, dairy cow fat, and siluriform fish muscle (i.e. catfish) to determine the current residue levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and non-ortho-polychlorinated biphenyls (no-PCBs). The following types of fat samples were analysed: beef from heifers and steers (referred to as "beef"), pork, chicken, turkey, dairy cow (referred to as "dairy cow"), and siluriform fish muscle, which includes catfish. The survey is conducted every 5 years. Fat samples for each slaughter class and siluriform fillets were collected from U.S. federally inspected slaughter facilities, processed, and analysed for 17 PCDD/Fs and 3 no-PCBs. Toxic equivalency concentrations were calculated using 2005 toxic equivalency factors and summed (sum-TEQ) for all slaughter classes. The sum-TEQs ranged from non-detect (nd) to 16.5 pg TEQ/g lipid. The median sum-TEQs, when nd = ½ LOD, for beef, pork, chicken, turkey, dairy cow, and siluriform fish were 0.48, 0.08, 0.07, 0.21, 0.38, and 0.62 pg TEQ/g lipid (wet weight for siluriform fish), respectively. A comparison of the current and previous surveys typically depicts a significant declining trend depending on the slaughter class (such as chicken and turkey), however, beef and pork fat median values slightly increased and decreased, respectively, but neither were significant compared to the previous survey. The congener patterns for some high concentration beef and pork fat samples suggested that pentachlorophenol treated wood continues to be a likely on-farm dioxin exposure source.

Modeling cost-effective monitoring schemes for food safety contaminants: Case study for dioxins in the dairy supply chain

Food safety monitoring is essential for hazard identification in food chain, but its application may be limited due to costly analytical methods and (inefficient) sampling procedures. The objective of this study was to design cost-effective monitoring schemes for food safety contaminants along the food production chain, given restricted monitoring budgets. As a case study, we focused on dioxins in the dairy supply chain with feed mills, dairy farms, dairy trucks and storage silos in dairy plants as possible control points. The cost-effectiveness of monitoring schemes was assessed using a model consisting of a simulation module and an optimization module. In the simulation module, the probability to collect at least one contaminated sample was computed for different sampling strategies (simple random sampling, stratified random sampling and systematic sampling) at each control point. The optimization module maximized the effectiveness of a monitoring scheme to identify the contaminated sample by determining the optimal sampling strategies, the optimal number of incremental samples collected, and the pooling rate (number of collected samples mixed into one aggregated sample) at each control point. The modelling approach was applied to two cases with different types of contamination. Results of these cases showed that, to identify the same contaminated sample, monitoring schemes with systematic sampling were more cost-effective at feed mills and dairy farms. The combination of simulation and optimization methods showed to be useful for developing cost-effective food safety monitoring schemes along the food supply chain.

High levels of dioxins and PCBs in meat, fat and livers of free ranging pigs, goats, sheep and cows from the island of Curaçao

Samples of adipose tissue, meat and livers from pigs, cows, sheep and goats from Curaçao were analysed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like (dl-) and non-dioxin-like (ndl-) PCBs (polychlorinated biphenyls). Levels in many samples of adipose tissue were higher than the EU maximum levels (MLs) for PCDD/Fs and the sum of PCDD/Fs and dl-PCBs (sum-TEQ), indicating unusually high levels. Median sum-TEQ (Toxic Equivalents) levels for pigs, cows, sheep and goats were 0.9 (range 0.3-35), 3.0 (0.5-14), 5.7 (0.3-28) and 6.5 (0.5-134) pg TEQ g^-1 fat. For most samples, the congener pattern pointed to the burning of waste as the major source, in line with the fact that most animals forage outside. MLs for ndl-PCBs were also exceeded in some of the samples, indicating that some areas are additionally contaminated with PCBs. Meat levels showed similar lipid based levels as adipose tissue, contrary to liver levels, which were much higher in most animals. Pigs showed liver sequestration at lower levels in adipose tissue than the ruminants. The relatively high levels observed in this study are likely to result in high exposure of consumers and measures were taken to reduce the contamination of areas where animals forage.

Rapid extraction of total lipids and lipophilic POPs from all EU-regulated foods of animal origin: Smedes' method revisited and enhanced

BACKGROUND

Persistent organic pollutants (POPs) such as dioxins, dioxin-like chemicals and non-dioxin-like PCBs causing adverse effects to human health bio-accumulate through the food web due to their affinity for adipose tissues. Foods of animal origin are therefore the main contributors to human dietary exposure. The European Union's (EU) food safety policy requires checking of a wide range of samples for compliance with legal limits on a regular basis. Several methods of varying efficiency are applied by official control laboratories for extraction of the different classes of lipids and associated POPs, bound to animal tissue and animal products in varying degrees, sometimes leading to discrepancies especially in fresh weight based analytical results.

RESULTS

Starting from Smedes' lipid extraction from marine tissue, we optimized the extraction efficiency for both lipids and lipophilic pollutants, abandoning the time-consuming centrifugation step. The resulting modified Smedes extraction (MSE) method was validated based on multiple analyses of a large number of real world samples, matrix calibration and performance assessment in proficiency testing utilizing both instrumental and bioanalytical methodologies. Intermediate precision in 12 different foods was below 3% in chicken eggs, egg powder, animal fat, fish, fish oil, poultry, whole milk, milk fat and milk powder, and below 5% in bovine meat, liver, and infant food. In comparison to Twisselmann hot extraction, results presented here show an increased efficiency of MSE by +25% for bovine liver, +14% for chicken eggs, +13% for poultry meat, +12% for fish, 8% for bovine meat, and 6% for infant food.

CONCLUSIONS

For the first time, a fast and reliable routine method is available that enables the analyst to reproducibly extract "total" lipids from any EU-regulated food sample of animal origin within 6 to 8 minutes. Increased efficiency translates into a considerable increase in both lipid and wet weight-based analytical results measured for associated POPs, reducing the risk of false non-compliant results. Compared to a 4 hour Twisselmann extraction, the extraction of 1000 samples using MSE would result in annual savings of about 250 hours or 32 working days. Our MSE procedure contributes to the European Commission's objective of harmonising analytical results across the EU generated according to Commission Regulation (EU) 2017/644.

Persistent Organic Pollutants in Food: Contamination Sources, Health Effects and Detection Methods

Persistent organic pollutants (POPs) present in foods have been a major concern for food safety due to their persistence and toxic effects. To ensure food safety and protect human health from POPs, it is critical to achieve a better understanding of POP pathways into food and develop strategies to reduce human exposure. POPs could present in food in the raw stages, transferred from the environment or artificially introduced during food preparation steps. Exposure to these pollutants may cause various health problems such as endocrine disruption, cardiovascular diseases, cancers, diabetes, birth defects, and dysfunctional immune and reproductive systems. This review describes potential sources of POP food contamination, analytical approaches to measure POP levels in food and efforts to control food contamination with POPs.

Application of a risk-based standardized animal biomonitoring approach to contaminated sites

Biomonitoring has been used to disclose the public health impact of contaminated sites. This study aimed at setting up good practices to apply biomonitoring targeting animal matrixes to design risk-based surveillance and exposure assessment plans. A nine-step protocol targeting farmed animals was devised and tested in three case study areas including (1) a waste dump, (2) a waste incinerator, and (3) a secondary aluminum smelter. Between 2010 and 2012, in each study area, the following 9-step best practices were applied: hazard identification, GIS project creation, risk area delimitation, control area selection, receptors (livestock) identification, farms and matrixes selection, sampling study design, on-farm secondary sources exclusion, and statistical and geostatistical analysis. Dairy farms and free-range laying hens were the primary targets: eggs from both risk and control areas and milk from risk areas were sampled and submitted for detection of selected tracking contaminants compatible with the putative sources. Comparison data (risk vs. control) of heavy metal concentrations in eggs were available only for case study 2, whereas egg comparison data of persistent organic pollutants were available for all the risk-control pairs. After taking into account potential secondary sources, no concern from metals was arisen, whereas high concentrations of persistent organic pollutants were detected in all risk areas; however, only for the aluminum smelter case study, the contamination was broad and higher in the risk area compared with the control one. The protocol has proved to be easily applicable and flexible to varying contexts and able to provide helpful data to inform risk management decisions.

PCDDs, PCDFs and PCBs in locally produced foods as health risk factors in Silesia Province, Poland

Dioxins (PCDDs), furans (PCDFs) and polychlorinated biphenyls (PCBs) emitted into the environment can accumulate in foods and become a significant source of dietary exposure for consumers of these compounds. This study aims to assess the dietary exposure of the residents in a rural area of the Silesia region in southern Poland to PCDDs, PCDFs and PCBs. The goal is to estimate cancer and non-cancer health risks due to the consumption of foods of animal origin. The area has relatively higher concentration of PCDDs, PCDFs and PCBs in the air in comparison to large industrialized cities of the Silesia province. Three popular foods of animal origin, namely free-range chicken meat, free-range chicken eggs, and cow milk produced in the farms were used. The control samples were the same foods from the local grocery stores. Two exposure scenarios were considered: Firstly that residents consumed free-range foods and secondly that the food items were purchased from stores in the study area. In the first scenario, exposure to concentrations of PCDDs, PCDFs, and dioxin-like PCBs (dl-PCBs) yielded evidence of elevated cancer and non-cancer risks. The hazard quotient (HQ) was 71.3 for non-cancer risk and 7.5 × 10^-3 for cancer risk. The health risk from exposure to PCDDs, PCDFs and dl-PCBs in the second scenario was 6.9 × 10^-4 and HQ = 0.8, respectively. Implementation of educational activities in the study area is needed to increase the resident's awareness of the risks associated with the emissions of chlorinated persistent organic pollutants to the environment, including aspects such as the main sources of the emission and how to avoid exposure to these compounds.

Concentrations of environmental organic contaminants in meat and meat products and human dietary exposure: A review

Meat and meat products is one of the most relevant food groups in an important number of human diets. Recently, the IARC, based on results of a number of epidemiological studies, classified the consumptions of red meat and processed meat as "probably carcinogenic to humans" and as "carcinogenic to humans", respectively. It was suggested that the substances responsible of the potential carcinogenicity would be mainly generated during meat processing, such as curing and smoking, or when meat is heated at high temperatures. However, the exposure to environmental pollutants through meat consumption was not discussed. The purpose of the present paper was to review recent studies reporting the concentrations of PCDD/Fs, DL-PCBs and PAHs in meat and meat products, as well as the human exposure to these pollutants through the diet. It is concluded that the health risks derived from exposure to carcinogenic environmental contaminants must be considered in the context of each specific diet, which besides meat and meat products, includes other foodstuffs containing also chemical pollutants, some of them with carcinogenic potential. Anyhow, meat and meat products are not the main food group responsible of the dietary exposure to carcinogenic (or probably carcinogenic) environmental organic pollutants.