Microbial contamination is inevitable for raw and/or minimally processed ready-to-eat foods. As a consequence of the pathogenic bacterial contamination, the risk of food-borne illness increases during distribution and storage until consumption. Prediction of microbial growth and/or inactivation in/on those foods provides important information for ensuring the microbial food safety. Although numerous predictive models for bacterial growth have been proposed for various microorganisms, this review focuses on the modeling of pathogenic bacterial growth in raw and minimally processed ready-to-eat foods such as fresh-cut produce and raw minced-tuna, a common ingredient for sushi. The growth models described here take into account both the environment temperature and microbial competition in the food matrix. Microbial competition plays a key role in real food environments. Food-based predictive models enable not only to directly estimate the microbial growth on those foods, but also to apply to validation of culture-medium-based predictive models. Furthermore, toward a development of accurate and/or realistic bacterial dose-response models, a model for inactivation of pathogenic bacteria during simulated gastric fluid is also introduced.
Consumer demand for shiitake mushrooms is increasing. However, food safety information regarding the prevalence of microbial pathogens on the products sold via the Internet or at local retail markets is limited. The present study was conducted to assess the microbial load on shiitake mushrooms sold through the Internet and at local (central Virginia) retail markets. A total of 90 shiitake mushroom products, consisting of locally-purchased whole (LW) and sliced (LS) and Internet-procured whole (IW), sliced (IS), and powdered (IP) forms, were tested. High levels of aerobic mesophiles (6.9 ± 1.3 to 7.5 ± 1.1 log CFU/g), yeast and mold (5.8 ± 0.9 to 6.0 ± 0.3 log CFU/g), and coliforms (1.6 ± 1.0 to 1.9 ± 1.1 log MPN/g) were found in locally-acquired mushrooms. One LW sample and 2 of LS contained Listeria spp. Our findings suggest that shiitake mushroom producers and retailers need to be aware of potential microbial hazards associated with handling fresh shiitake mushrooms and consumers should take appropriate precautions when handling fresh shiitake mushrooms to prevent cross-contamination and possible foodborne illness in the home.
The Food Safety Commission of Japan (FSCJ) conducted a risk assessment of prednisolone (CAS No. 50-24-8), a steroidal anti-inflammatory agent, using the evaluation reports of EMA (EMEA) and documents for the re-evaluation* of veterinary medicinal products. All the genotoxicity studies in vivo were negative, although some of in vitro genotoxicity studies showed positive results. Prednisolone was thus judged to have no genotoxicity relevant to human health. FSCJ concluded it possible to specify an acceptable daily intake (ADI) of prednisolone. Major adverse effects of prednisolone observed are reduced counts of leukocyte and decreased weighs of the thymus, spleen and adrenal gland. Slight decreases were also observed on bone marrow cells. There is no substantial evidence to suggest the carcinogenicity of prednisolone. Prednisolone treatment resulted in an increased rate of embryonal resorption and a decrease of fetal body weights in a developmental toxicity study in rats. No teratogenicity was observed. FSCJ specified an ADI of 0.00025 mg/kg bw/day (0.25 µg/kg bw/day) for prednisolone applying a safety factor of 1,000 to the LOAEL of 0.25 mg/kg bw/day obtained from the LOAEL of prednisone in 18-month carcinogenicity study in mice.
The Food Safety Commission of Japan (FSCJ) conducted a risk assessment of methylprednisolone (CAS No. 83-43-2), a steroidal anti-inflammatory agent, using the evaluation reports from EMA (EMEA) and other related documents. Although no genotoxicty study in vivo was available, all the genotoxicity studies in vitro were negative. In addition, prednisolone, a structural analogue of methylprednisolone, is judged to have no genotoxicity relevant to human health. Thus, methylprednisolone is considered to have no genotoxicity relevant to human health. Therefore, FSCJ concluded it possible to specify an acceptable daily intake (ADI) of methylprednisolone. Major adverse effects of methylprednisolone observed are reduced counts of leukocyte, thymic atrophy, decreased weights of spleen, and glycogen accumulation in hepatocyte. FSCJ specified an ADI of 0.0003 mg/kg bw/day for methylprednisolone applying a safety factor of 1,000 to the LOAEL of 0.3 mg/kg bw/day in the 63-day subacute toxicity study in rats.
The Food Safety Commission of Japan (FSCJ) conducted a risk assessment of picarbutrazox (CAS No.500207-04-5), a methyltetrazole-type fungicide, based on results from various studies. Major adverse effects of picarbutrazox were observed as hepatocellular hypertrophy and hypertrophy of follicular epithelial cells in rats. None of neurotoxicity, reproductive toxicity, teratogenicity and genotoxicity were detected in the experiments described above. Picarbutrazox (parent compound only) and its metabolite B were identified as the relevant substance for the residue definition for dietary risk assessment in agricultural products. The lowest no-observed-adverse-effect level (NOAEL) obtained in all studies was 2.34 mg/kg bw/day in a two-year combined chronic toxicity/carcinogenicity study in rats. FSCJ specified an acceptable daily intake (ADI) of 0.023 mg/kg bw/day, applying a safety factor of 100 to the NOAEL. FSCJ judged it unnecessary to specify an acute reference dose (ARfD), since no adverse effects would be likely to be elicited by a single oral administration.