Exposure to nitrate from food and drinking-water in New Zealand. Can these be considered separately?

Recent epidemiological studies have reported associations between colorectal cancer incidence and nitrates in drinking-water, but not from the diet. The toxicokinetics of nitrates were reviewed and exposure data from New Zealand were analysed. Dietary (including drinking-water) exposure of New Zealanders to nitrates was found to be very similar to most other countries and within internationally-established acceptable daily intakes. Less than 10% of nitrate exposure was from drinking-water, with little difference between adults and children. Approximately half of the total water-based exposure is through water alone, the remainder was consumed as tea and coffee (adults), or water-based fruit drinks (children). For children, drinking-water as a beverage is generally consumed close to a meal time, with 83% of servings consumed within an hour of eating. For adults, this is reduced to 51% of servings consumed within an hour of a meal. Only 2.6% of nitrate exposure for adults and 0.7% of nitrate exposure for children is from drinking-water consumed on its own and not in close temporal association to food consumption. It was concluded from the combination of the biology and the exposure assessment that there is little reason to differentiate between drinking-water and food nitrate exposure.

Mercury, methylmercury and long-chain polyunsaturated fatty acids in selected fish species and comparison of approaches to risk-benefit analysis.

Fish (n = 281) of six species, caught in New Zealand waters, were analysed for total mercury (t-Hg), methylmercury (MeHg) and the long-chain polyunsaturated fatty acids, eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA). Mean t-Hg and MeHg concentrations for the six species were in the range 0.06-0.53 mg/kg and 0.06-0.46 mg/kg, respectively. The mean proportion of t-Hg present as MeHg for the six species considered was in the range 83-93%. Positive associations were observed between t-Hg and MeHg content of fish and measures of fish size (length, weight), although the strength of the associations was species dependent. The mean EPA + DHA content of the six fish species varied in the range 2.0-20.5 mg/g. Two approaches were trialled to compare the risks, due to MeHg, and the benefits, due to EPA and DHA, from consumption of the six fish species. Both approaches identify that for these six fish species the benefits of normal patterns of fish consumption on offspring IQ largely outweigh the risks from MeHg.

Expert Elicitation for Estimation of the Proportion Foodborne for Selected Microbial Pathogens in New Zealand.

Objectives: To estimate the proportions of human cases of nine specific microbial diseases in New Zealand that were due to transmission by food and the proportion of the foodborne burden that was due to transmission by some specific foods. Materials and Methods: Subjective probability distributions were elicited from 10 food safety experts using a modified Delphi approach. In addition to uniform weighting of experts' opinions, two techniques were used to measure individual's expertise; self-assessment and performance-based weighting using Cooke's classical method. Aggregate estimates were derived by simulation. Results: Food was estimated to be the primary route of transmission for infections due to Campylobacter spp., Listeria monocytogenes, nontyphoid Salmonella spp., Vibrio parahaemolyticus, and Yersinia enterocolitica. Uncertainties were lowest for organisms where the self-assessed expertise level was highest. Conclusions: Foodborne proportion estimates were more "polarized" than for a similar elicitation in 2005. That is, where food was the primary transmission route the estimated proportion on account of food was higher (62.1-90.6% in the current study for self-assessed expertise weighted estimates, compared to 56.2-89.2% in 2005); where food was not the primary transmission route the estimated proportion because of food was lower (27.6-34.0% in the current study compared to 31.5-39.5% in 2005). These estimates represent an essential resource for determining the burden of foodborne disease in New Zealand.

Harmonized methodology to assess chronic dietary exposure to residues from compounds used as pesticide and veterinary drug.

Risk assessments for pesticide and veterinary drug residues in food are performed respectively by the Joint FAO/WHO Expert Meeting on Pesticide Residues (JMPR) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The models used by the two Committees to assess chronic dietary exposure are based on different data and assumptions which may be confusing, particularly for risk managers, when the same compound is used to treat plants and animals. This publication details the results of combined chronic dietary exposure assessments for eight compounds used both as pesticide and veterinary drugs. It compares the results from models in use by JMPR and JECFA with those from national estimates performed by 17 countries. Results show that the JECFA model is better reflecting less than lifetime dietary exposure by considering consumption of children and high consumers. The JMPR model is a suitable model for estimating average chronic (lifetime) exposure to residues present in widely and regularly consumed staple commodities. However, it is suitable neither for estimating children's exposure nor more generally for assessing less than lifetime dietary exposure. In order to select the appropriate exposure model related to the occurrence of adverse effects i.e. effects occurring over less-than-lifetime or effects occurring only over lifetime, this paper proposes criteria to match the toxicological profile of the compound and the appropriate exposure scenarios. These approaches will continue to be harmonized to ensure the most scientifically sound basis for the risk assessment for pesticides and veterinary drug residues and consequently for other chemicals in food.

Metabolism of cyanogenic glycosides: A review.

Potential toxicity of cyanogenic glycosides arises from enzymatic degradation to produce hydrogen cyanide. Information on the metabolism of cyanogenic glycosides is available from in vitro, animal and human studies. In the absence of ß-glucosidase enzymes from the source plant material, two processes appear to contribute to the production of cyanide from cyanogenic glycosides; the proportion of the glycoside dose that reaches the large intestine, where most of the bacterial hydrolysis occurs, and the rate of hydrolysis of cyanogenic glycosides to cyanohydrin and cyanide. Some cyanogenic glycosides, such as prunasin, are actively absorbed in the jejunum by utilising the epithelial sodium-dependent monosaccharide transporter (SGLT1). The rate of cyanide production from cyanogenic glycosides due to bacterial ß-glycosidase activity depends on; the sugar moiety in the molecule and the stability of the intermediate cyanohydrin following hydrolysis by bacterial ß-glucosidase. Cyanogenic glycosides with a gentiobiose sugar, amygdalin, linustatin, and neolinustatin, undergo a two stage hydrolysis, with gentiobiose initially being hydrolysed to glucose to form prunasin, linamarin and lotaustralin, respectively. While the overall impact of these metabolic factors is difficult to predict, the toxicity of cyanogenic glycosides will be less than the toxicity suggested by their theoretical hydrocyanic acid equivalents.

Identification of Biological Hazards in Produce Consumed in Industrialized Countries: A Review.

Microbial contamination of fresh produce (fresh fruits and vegetables) poses serious public health concerns worldwide. This study was conducted as a comprehensive analysis of biological hazards in the global fresh produce chain. Data about produce-related outbreaks and illness were collected from the annual reports and databases of foodborne outbreak surveillance systems in different regions and countries from 2010 to 2015. The global patterns of and regional differences in documented outbreaks and cases were analyzed, and produce commodities and pathogens of greatest concern were identified. Data on sporadic illnesses were also collected through a comprehensive literature review of case-control studies. We found 988 produce-related outbreaks (with known agents) and 45,723 cases in all regions and countries. The numbers of produce-related outbreaks per million person-years were approximately 0.76, 0.26, 0.25, 0.13, 0.12, and 0.05 in New Zealand, Australia, the United States, the European Union, Canada, and Japan, respectively. The top three food categories and pathogens contributing to produce-related outbreaks were vegetables and nonfruits (i.e., food other than fruits; 27.0%), unspecified vegetables (12.2%), and vegetable row crops (11.7%) and norovirus (42.4%), Salmonella enterica (19.9%), and Staphylococcus aureus (7.9%), respectively. Produce consumption was identified as a protective factor, a risk factor, and either a protective or risk factor for sporadic illnesses in 11, 5, and 5 studies, respectively, among 21 case-control studies. Risks associated with produce consumption in the United States and the European Union have been linked to various factors such as irrigation water, cross-contamination, storage time and temperature abuse, infected food handlers, and unprocessed contaminated ingredients. The results of the current study indicate the complexity of produce products consumed across the globe and the difficulty in tracing illnesses back to specific food ingredients.

Understanding staff perspectives of quality in practice in healthcare.

BACKGROUND: Extensive work has been focussed on developing and analysing different performance and quality measures in health services. However less has been published on how practitioners understand and assess performance and the quality of care in routine practice. This paper explores how health service staff understand and assess their own performance and quality of their day to day work. Asking staff how they knew they were doing a good job, it explored the values, motivations and behaviours of staff in relation to healthcare performance. The paper illustrates how staff perceptions of quality and performance are often based on different logics to the dominant notions of performance and quality embedded in current policy. METHODS: Using grounded theory and qualitative, in-depth interviews this research studied how primary care staff understood and assessed their own performance and quality in everyday practice. 21 people were interviewed, comprising of health visitors, occupational therapists, managers, human resources staff and administrators. Analytic themes were developed using open and axial coding. RESULTS: Diverse aspects of quality and performance in healthcare are rooted in differing organisational logics. Staff values and personal and professional standards are an essential element in understanding how quality is co-produced in everyday service interactions. Tensions can exist between patient centred, relational care and the pressures of efficiency and rationalisation. CONCLUSIONS: Understanding the perspectives of staff in relation to how quality in practice develops helps us to reflect on different mechanisms to manage quality. Quality in everyday practice relies upon staff values, motivations and behaviours and how staff interact with patients, putting both explicit and tacit knowledge into specific action. However organisational systems that manage quality often operate on the basis of rational measurement. These do not always incorporate the intangible, relational and tacit dimensions of care. Management models need to account for these relational and experiential aspects of care quality to support the prioritisation of patients' needs. Services management, knowledge management and ethics of care literature can provide stronger theoretical building blocks to understand how to manage quality in practice.

Energy drink consumption and impact on caffeine risk.

The impact of caffeine from energy drinks occurs against a background exposure from naturally occurring caffeine (coffee, tea, cocoa and foods containing these ingredients) and caffeinated beverages (kola-type soft drinks). Background caffeine exposure, excluding energy drinks, was assessed for six New Zealand population groups aged 15 years and over (n = 4503) by combining concentration data for 53 caffeine-containing foods with consumption information from the 2008/09 New Zealand Adult Nutrition Survey (ANS). Caffeine exposure for those who consumed energy drinks (n = 138) was similarly assessed, with inclusion of energy drinks. Forty-seven energy drink products were identified on the New Zealand market in 2010. Product volumes ranged from 30 to 600 ml per unit, resulting in exposures of 10-300 mg caffeine per retail unit consumed. A small percentage, 3.1%, of New Zealanders reported consuming energy drinks, with most energy drink consumers (110/138) drinking one serving per 24 h. The maximum number of energy drinks consumed per 24 h was 14 (total caffeine of 390 mg). A high degree of brand loyalty was evident. Since only a minor proportion of New Zealanders reported consuming energy drinks, a greater number of New Zealanders exceeded a potentially adverse effect level (AEL) of 3 mg kg(-1) bw day(-1) for caffeine from caffeine-containing foods than from energy drinks. Energy drink consumption is not a risk at a population level because of the low prevalence of consumption. At an individual level, however, teenagers, adults (20-64 years) and females (16-44 years) were more likely to exceed the AEL by consuming energy drinks in combination with caffeine-containing foods.

Cyanogenic glycosides in plant-based foods available in New Zealand.

Cyanogenic glycosides occur in a wide range of plant species. The potential toxicity of cyanogenic glycosides arises from enzymatic degradation to produce hydrogen cyanide, which may result in acute cyanide poisoning and has also been implicated in the aetiology of several chronic diseases. One hundred retail foods were sampled and analysed for the presence of total hydrocyanic acid using an acid hydrolysis-isonicotinic/barbituric acid colourimetric method. Food samples included cassava, bamboo shoots, almonds and almond products, pome fruit products, flaxseed/linseed, stone fruit products, lima beans, and various seeds and miscellaneous products, including taro leaves, passion fruit, spinach and canned stuffed vine leaves. The concentrations of total hydrocyanic acid (the hydrocyanic acid equivalents of all cyanogenic compounds) found were consistent with or lower than concentrations reported in the scientific literature. Linseed/flaxseed contained the highest concentrations of total hydrocyanic acid of any of the analysed foods (91-178 mg kg(-1)). Linseed-containing breads were found to contain total hydrocyanic acid at concentrations expected from their linseed content, indicating little impact of processing on the total hydrocyanic acid content. Simulation modelling was used to assess the risk due to the total hydrocyanic acid in fruit juice and linseed-containing bread. 

Predictive modelling of interventions to improve iodine intake in New Zealand.

OBJECTIVE: The potential effects of four interventions to improve iodine intakes of six New Zealand population groups are assessed. DESIGN: A model was developed to estimate iodine intake when (i) bread is manufactured with or without iodized salt, (ii) recommended foods are consumed to augment iodine intake, (iii) iodine supplementation as recommended for pregnant women is taken and (iv) the level of iodization for use in bread manufacture is doubled from 25-65 mg to 100 mg iodine/kg salt. SETTING: New Zealanders have low and decreasing iodine intakes and low iodine status. Predictive modelling is a useful tool to assess the likely impact, and potential risk, of nutrition interventions. SUBJECTS: Food consumption information was sourced from 24 h diet recall records for 4576 New Zealanders aged over 5 years. RESULTS: Most consumers (73-100 %) are predicted to achieve an adequate iodine intake when salt iodized at 25-65 mg iodine/kg salt is used in bread manufacture, except in pregnant females of whom 37 % are likely to meet the estimated average requirement. Current dietary advice to achieve estimated average requirements is challenging for some consumers. Pregnant women are predicted to achieve adequate but not excessive iodine intakes when 150 µg of supplemental iodine is taken daily, assuming iodized salt in bread. CONCLUSIONS: The manufacture of bread with iodized salt and supplemental iodine for pregnant women are predicted to be effective interventions to lift iodine intakes in New Zealand. Current estimations of iodine intake will be improved with information on discretionary salt and supplemental iodine usage.

Estimated dietary fluoride intake for New Zealanders.

OBJECTIVES: Existing fluoride concentration and consumption data were used to estimate fluoride intakes from the diet and toothpaste use, for New Zealand subpopulations, to identify any population groups at risk of high-fluoride intake. METHODS: For each sub-population, two separate dietary intake estimates were made--one based on a non-fluoridated water supply (fluoride concentration of 0.1 mg/L), and the other based on a water supply fluoridated to a concentration of 1.0 mg/L. Fluoride concentration data were taken from historical surveys, while food consumption data were taken from national 24-hour dietary recall surveys or from simulated diets. RESULTS: Mean and 95th percentile estimations of dietary fluoride intake were well below the upper level of intake (UL), whether intakes were calculated on the basis of a non-fluoridated or fluoridated water supply. The use of fluoride-containing toothpastes provides additional fluoride intake. For many of the population groups considered, mean fluoride intakes were below the adequate intake (AI) level for caries protection, even after inclusion of the fluoride contribution from toothpaste. Intake of fluoride was driven by consumption of dietary staples (bread, potatoes),beverages (particularly tea, soft drinks, and beer), and the fluoride status of drinking water. CONCLUSION: Estimates of fluoride intake from the diet and toothpaste did not identify any groups at risk of exceeding the UL, with the exception of infants (6-12 months) living in areas with fluoridated water supplies and using high-fluoride toothpaste. In contrast, much of the adult population may be receiving insufficient fluoride for optimum caries protection from these sources, as represented by the AI.

Dietary fluoride intake for fully formula-fed infants in New Zealand: impact of formula and water fluoride.

OBJECTIVE: A survey of the fluoride content of infant and toddler formulae available on the New Zealand market was conducted. Results were used to estimate the dietary fluoride intake for a fully formula-fed infant. METHODS: Infant and toddler formulae were prepared according to manufacturers' instructions with fluoride-free water and analyzed for fluoride by a modification of the microdiffusion method of Taves. A proportion of samples were reanalyzed after reconstitution with water at fluoride concentrations of 0.7 and 1.0 mg/L. A stochastic model was used to estimate dietary fluoride intake. RESULTS: The mean fluoride content of prepared infant formulae was 0.069 mg/L. When formulae were prepared with water of differing fluoride concentrations, the fluoride concentration was found to be a simple linear function of water fluoride concentration. Estimates of dietary fluoride intake for infants consuming formuae prepared with fluoride-free water were well below the upper level of intake (UL) for New Zealand and Australia (0.7 mg/day). At water fluoride concentrations of 0.7 and 1.0 mg/L the UL would be exceeded 30 and 93 percent of the time, respectively. CONCLUSIONS: The fluoride content of water used to reconstitute infant formulae has a greater impact on fluoride intake of fully formula-fed infants than the fluoride content of the powdered infant formulae. Infants fully formula-fed on formulae prepared with optimally fluoridated water (0.7-1.0 mg/L) have a high probability of exceeding the UL for fluoride and are at increased risk of dental fluorosis.

Risk ranking for foodborne microbial hazards in New Zealand: burden of disease estimates.

Priority setting for food safety management at a national level requires risks to be ranked according to defined criteria. In this study, two approaches (disability-adjusted life years (DALYs) and cost of illness (COI)) were used to generate estimates of the burden of disease for certain potentially foodborne diseases (campylobacteriosis, salmonellosis, listeriosis (invasive, perinatal, and nonperinatal), infection with Shiga toxin-producing Escherichia coli (STEC), yersiniosis, and norovirus infection) and their sequelae in New Zealand. A modified Delphi approach was used to estimate the food-attributable proportion for these diseases. The two approaches gave a similar ranking for the selected diseases, with campylobacteriosis and its sequelae accounting for the greatest proportion of the overall burden of disease by far.

Ranking the risk of pesticide dietary intake.

Pesticide residues in various foods were assessed for the relative risk to the consumer. The analysis took into account criteria such as a pesticide's toxicity, usage, frequency of occurrence in foods, frequency of Maximum Residue Level (MRL) exceedances, and the overall risks of specific pesticide/food combinations. Examination of the top ten ranked pesticides for each criterion showed that there are no trends of commonality. Thus, no single pesticide is of particular concern from a consumer's point of view. This suggests that the consumer's risk perception is likely to be higher than justified.

Dietary exposure to xenoestrogens in New Zealand.

Continuing evidence of the feminising effects of xenoestrogens on a range of wildlife species increases the need to assess the human health risk of these estrogen mimics. We have estimated the exposure of New Zealand males, females and young men to a range of naturally occurring and synthetic xenoestrogens found in food. Only estrogenic compounds that act by interaction with the estrogen receptor have been included. Theoretical plasma estrogen activity levels were derived from estrogen exposure estimates and estrogenic potency data. Theoretical plasma levels were compared with published data for specific xenoestrogens. There was surprisingly close agreement. Xenoestrogenicity from dietary intake was almost equally attributed to naturally occurring and synthetic xenoestrogens. Relative contributions for a male, for example were isoflavones (genistein and daidzein) (36%) and bisphenol A (34%) with smaller contributions from alkyl phenols (18%) and the flavonoids (phloretin and kaempferol) (12%). It is suggested that dietary xenoestrogens might have a pharmacological effect on New Zealand males and postmenopausal women, but are unlikely to be significant for pre-menopausal women.