Susana Bayarri

Bioactive properties of a propolis-based dietary supplement and its use in combination with mild heat for apple juice preservation

This study characterizes the antioxidant and antibacterial properties of a propolis-based dietary supplement (PDS) and investigates its incorporation into apple juice to decrease the intensity of the heat treatment required to inactivate 5 log10 cycles of Escherichia coli O157:H7. As the source of propolis, we used a PDS containing 0.2 mg/μL of propylene glycol-extracted propolis (propolis). The total phenolic content and antioxidant activity (IC50) of the PDS were 82.15±3.53 mg/g and 0.055±0.003 mg/mL, respectively. Regarding antimicrobial activity, propolis (0.2 mg/mL) was very effective under acidic pH against Listeria monocytogenes EGD-e, inactivating more than 5 log10 cell cycles in 1h, but hardly inactivated or sub-lethally injured E. coli O157:H7 Sakai. However, incorporating propolis (0.2 mg/mL) into acidic buffer decreased the time needed to inactivate 5 log10 cycles of E. coli O157:H7 Sakai at 51 °C by more than 40 times. Moreover, when combined with heat in apple juice, propolis (0.1mg/mL) reduced the thermal treatment time and temperature needed to inactivate 5 log10 cycles of E. coli by 75% and 3 °C, respectively. The corresponding PDS concentration did not decrease the organoleptic properties of the apple juice, which implies the possibility of obtaining a sensorially appealing, low-pasteurized apple juice with the functional properties provided by propolis.

Toxoplasma gondii in Commercially Available Pork Meat and Cured Ham: A Contribution to Risk Assessment for Consumers

Toxoplasmosis is an infection caused by Toxoplasma gondii, whose transmission has usually been attributed to ingestion of undercooked or raw meat. Dry-cured ham is a high-quality meat product of increasing economic relevance, and epidemiological studies point to cured meat products as a risk factor for acquiring toxoplasmosis. With the aim of contributing to the risk assessment process, 50 samples of fresh pork meat and commercial cured ham were collected in the city of Zaragoza (northeastern Spain), and the presence of viable forms of T. gondii was analyzed. A mouse concentration bioassay technique was used, and the presence of the parasite in mice was determined by indirect immunofluorescence assay. T. gondii was detected in two samples of rib, reflecting a frequency of 8% positive fresh pork meat (4% positivity of total samples analyzed). Brains of seropositive mice were analyzed by histology and PCR, although the parasite was not isolated in the seroconverted mice. No viable forms were detected either in other types of fresh meat or in the samples of cured ham.

Determination of the viability of Toxoplasma gondii in cured ham using bioassay: influence of technological processing and food safety implications.

Toxoplasmosis is a zoonotic disease caused by the protozoan Toxoplasma gondii and distributed worldwide. Ingestion of viable cysts from infected raw or undercooked meat is an important route of horizontal transmission of the parasite to humans. Little information is available concerning the effect of commercial curing on cysts of T. gondii. This study is the first in which the influence of processing of cured ham on the viability of T. gondii has been evaluated, using bioassay to assess the risk of infection from eating this meat product. Naturally infected pigs were selected for the study, and a mouse concentration bioassay technique was used to demonstrate viable bradyzoites of T. gondii in porcine tissues and hams. No viable parasites were found in the final product (14 months of curing) based on results of the indirect immunofluorescence assay and histological and PCR analyses. Our results indicate that the consumption of hams cured as described here poses an insignificant risk of acquiring toxoplasmosis. However, additional studies are required to evaluate the safety of ham products cured under different conditions of curing time, salt, and nitrite concentration.

Risk assessment of PCDD/PCDFs and indicator PCBs contamination in Spanish commercial baby food

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) as well as polychlorinated biphenyls (PCBs) are ubiquitous highly toxic environmental pollutants which exhibit a potential risk for human health. PCDD/Fs and PCBs contamination has been measured in samples of commercial baby food products: processed cereal and meat-and-fish-based baby food, which were made of individual samples collected from Spanish markets and pharmacies. They all presented a low dioxin content with a mean concentration ranging between 0.014 pg WHO-TEQ g(-1) product for fish-based baby food and 0.089 pg WHO PCDD/Fs-TEQ g(-1) product for processed cereal containing gluten. The mean concentration of the sum of the seven indicator PCBs was between 0.03 ng g(-1) product for fish-based baby food and 0.29 ng g(-1) product for gluten-free cereals. The estimated PCDD/Fs and indicator PCBs mean daily intake through the consumption of this kind of food has been calculated taking into account body weight and food consumption data for children aged 6-12 months. In order to assess the health risk derived from the exposure to these pollutants in children during the first year of life, data concerning infant formulae contamination has been also considered.

DDT, DDT Metabolites, and Other Organochlorines as Affected by Thermal Processing in Three Commercial Cuts of Lamb

The chlorinated pesticides played an important role in the history of chemical crop protection as well as human hygiene. These compounds combine high insecticidal effectiveness with low mammalian toxicity, and provide long-lasting protection against a broad spectrum of insects due to their chemical stability. The recent development of trace analysis resulted in the knowledge of their persistence in all sections of our environment. They are not only persistent but also lipophilic and thereby accumulate in plant, animal, and human tissues. An increasing public concern about their ubiquitous occurrence and possible longterm effects in human health resulted in their use being banned in most industrialized countries (Concon 1988).

Toxoplasma gondii: Pig seroprevalence, associated risk factors and viability in fresh pork meat

This study was conducted on 161 fattening pig farms located in Aragón (Northeast Spain). Serum samples from 1200 pigs were tested for antibodies against T. gondii by indirect immunofluorescence assay (IFA). Antibodies to T. gondii (≥1:20) were detected in 301 pigs (24.52%). The seroprevalence observed in the present study indicates a widespread exposure to T. gondii, as seropositive pigs were found in 96.67% of the farms studied although low pig titers were determined. Risk factors associated with T. gondii seroprevalence were presence of cats in or around the farms, presence of dogs around the facilities, low number of animals in the farms, poor hygiene and bad maintenance of the farms. Finally, it was observed that where rodent baits were used, Toxoplasma prevalence was lower. Risk management measures including control of cats and rodents on the farms, among others, could help to reduce the observed prevalence levels. By mouse bioassay, T. gondii was detected in 73.7% and isolated from 42.1% of seropositive pigs and a significant relation between the titers of pigs and the presence and viability of T. gondii in the tissues was found. The detection of T. gondii is not possible by currently practiced meat inspection. Nevertheless, the increased probability of detecting viable forms of T. gondii in tissues of pigs with titers ≥1: 80 could be used as the cutoff for discriminating higher risk animals, and could be used as an effective control tool for the industry of cured meat products. In practical terms, we propose that this value could be used as a critical limit in the HACCP system.

Evaluation of Heavy Metals and Polycyclic Aromatic Hydrocarbons in Honeys from Different Origins

A survey of honey samples from different geographical and botanical origins, including some samples collected from a fire-affected area in Spain, was conducted to assess their content of heavy metals and polycyclic aromatic hydrocarbons (PAHs). The levels of the determined toxic elements (Pb, Cd, As, and Sn) were low and were in the range of those reported by other studies. In our work the total amount of heavy metals and Pb was higher in dark honeys than in pale honeys. In the collected samples, no detectable levels of the 15 PAHs studied were found. The obtained data served to assess the levels of heavy metals and PAHs in honey samples from different geographical and environmental origins and to contribute to the scarce data about pollutant content of this matrix. In light of these results, the analyzed samples do not pose any serious concern to human health, and the data obtained in this study could serve to contribute to the establishment of specific maximum limits for honey.

Toxoplasma gondii in Meat and Food Safety Implications - A Review

Nevertheless, there are many reasons for foodborne disease remaining a global public health challenge. As some diseases are controlled, others emerge as new threats. New agents of risk have occupied the ecological niche of those on which control pressure has been exerted, replacing the previous ones. The proportions of the population who are elderly, immunosuppressed or otherwise disproportionately susceptible to severe outcomes from foodborne diseases are growing in many countries. Globalization of the food supply has led to the rapid and widespread international distribution of foods. This fundamental fact has motivated a radical change in the modern systems of management of the food safety, forced to the search of new methods of risk assessment, more effective preventive systems, permanent research of new systems of identification of these agents, to the development of the epidemiology applied to the food hygiene and the application of much more effective methods in the complex world of the decision making.

Evaluation of daily intake of PCDD/Fs and indicator PCBs in formula-fed Spanish children

Human exposure to polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) occurs predominantly via food intake. In this study, the exposure assessment of these contaminants has been estimated for infant formula-fed children up to 1 year of age. PCDD/F concentrations in the infant formulae was low, ranging between 0.09 and 0.17 pg WHO-TEQ g−1 fat and between 0.30 and 0.46 pg WHO-TEQ g−1 fat when results were calculated with the lower and medium bound values, respectively. Indicator PCB contamination levels were below 1 ng g−1 fat in all cases. Thus, the estimated daily intake of PCDD/Fs and indicator PCBs for infants has been assessed taking into account the above-mentioned contamination levels as well as different scenarios of body weight and food consumption data for babies aged 0–12 months. The results vary in the different scenarios considered but, on the whole, the daily estimated dioxin and indicator PCBs intake of the average infant population due to the consumption of infant formulae does not exceed the tolerable daily intake (TDI) of 2 pg WHO-TEQ kg−1 bw day−1 recommended by the Scientific Committee on Food (available at http://ec.europa.eu/food/fs/sc/scf/out90_en.pdf) nor the threshold value of 10 ng kg−1 bw day−1 proposed by the Dutch National Institute of Health and Environment (RIVM) (Baars et al. 2001. Report no. 711701025, National Institute of Public Health and the Environment (RIVM), Bilthoven, The Netherlands).

Multiresidue determination of carcinogenic polycyclic aromatic hydrocarbons in honey by solid-phase extraction and high-performance liquid chromatography.

An analytical procedure based on solid-phase extraction, using ethyl acetate as the elution solvent, and high-performance liquid chromatography with fluorescence and diode array detection was developed for the identification and quantification of polycyclic aromatic hydrocarbons (PAHs) in honey. The method has been optimized and validated in accordance with Commission Regulation 333/2007 and Commission Decision 2002/657/EC. This method allows the identification of the 15 PAHs that should be monitored in food matrices, as proposed in 2002 by the Scientific Committee on Food and later by the European Union in the Commission Recommendation 2005/108/EC, because of their genotoxic and carcinogenic properties. The results of the validation study were in agreement with quality criteria described in European legislation in terms of sensitivity, accuracy, and ruggedness, and the method was applied to the analysis of 42 honey samples (21 from Spain and 21 from other regions). The honey samples were not contaminated by PAHs at detectable levels and thus could be marketed without health risk.