Evaluation of in vitro bioassays as a screening tool to monitor chemical hazards in cow's milk.

Studies on cow's milk have mainly focused on analyzing specific chemical groups and natural components. Therefore, in this study, we evaluated if effect-based in vitro methods could be used as a screening tool to monitor chemical hazards in milk. In total, 32 milk samples were collected from a Swedish dairy company throughout one year. These samples included conventional and organic semi-skimmed as well as raw milk. The milk samples were tested in five in vitro methods covering eight endpoints. These endpoints included cytotoxicity, endocrine disruption (estrogen/androgen induction/inhibition), aryl hydrocarbon receptor activity, oxidative stress and DNA damage. Estrogen and androgen receptor inhibition, in addition to aryl hydrocarbon receptor activity, were the most responsive endpoints, where 10 to 13 out of the 32 milk samples were bioactive. Organic and conventional milk showed no major differences. Overall, no or only low activities were observed in milk samples in the remaining in vitro assays, which is a promising result with regard to applying effect-based methods as a screening tool. Concerning the most responsive assays, more research is needed to understand the normal background variations before they can be used as a screening tool for chemical hazards in milk.

An in vitro-based hazard assessment of liquid smoke food flavourings.

Liquid smoke products are widely used as a food additive to create a desired smoke flavour. These products may contain hazardous chemicals generated during the wood-burning process. However, the toxic effects of these types of hazardous chemicals constituting in the commercially available products are largely unknown. Therefore, a test battery of cell-based in vitro methods, covering different modes of actions of high relevance to human health, was applied to study liquid smoke products. Ten liquid smoke flavourings were tested as non-extracted and extracted. To assess the potential drivers of toxicity, we used two different solvents. The battery of in vitro methods covered estrogenicity, androgenicity, oxidative stress, aryl hydrocarbon receptor activity and genotoxicity. The non-extracted samples were tested at concentrations 0.002 to 1 µL liquid smoke flavouring/mL culture medium, while extracted samples were tested from 0.003 to 200 µL/mL. Genotoxicity was observed for nearly all non-extracted and all hexane-extracted samples, in which the former had higher potency. No genotoxicity was observed for ethyl acetate-extracted samples. Oxidative stress was activated by almost all extracted and non-extracted samples, while approximately half of the samples had aryl hydrocarbon receptor and estrogen receptor activities. This study used effect-based methods to evaluate the complex mixtures of liquid smoke flavourings. The increased bioactivities seen upon extractions indicate that non-polar chemicals are driving the genotoxicity, while polar substances are increasing oxidative stress and cytotoxic responses. The differences in responses indicate that non-extracted products contain chemicals that are able to antagonize toxic effects, and upon extraction, the protective substances are lost.

Food contact materials: an effect-based evaluation of the presence of hazardous chemicals in paper and cardboard packaging.

Food contact materials (FCMs) can contain hazardous chemicals that may have the potential to migrate into food and pose a health hazard for humans. Previous studies have mainly focused on plastic materials, while data on packaging materials made from paper and cardboard are limited. We used a panel of cell-based bioassays to investigate the presence and impact of bioactive chemicals on human relevant endpoints like oxidative stress, genotoxicity, inflammation, xenobiotic metabolism and endocrine system effects in extracts made from paper and cardboard. In total, 23 methanol extracts of commonly used paper and cardboard available on the Swedish market were extracted as a whole product using methanol to retrieve polar substances, and tested at concentrations 0.3-10 mg/mL and 0.2-6 mg/mL. At the highest concentration bioactivities were observed in a high proportion of the samples: oxidative stress (52%), genotoxicity (100%), xenobiotic metabolism (74%), antiandrogenic- (52%) and antioestrogenic receptor (39%). Packages of potential concern included cake/pastry boxes/mats, boxes for infant formula/skimmed milk, pizza boxes, pizza slice trays and bag of cookies. It should be noted that the extraction for packages like cake/pastry boxes can be considered exaggerated, as the exposure usually is shorter. It can be hypothesised that the observed responses may be explained by inks, coatings, contaminants and/or naturally occurring compounds within the material. To summarise, an effect-based approach enables hazard identification of chemicals within FCMs, which is a valuable tool for ensuring safe use of FCMs.