Determination of potential volatile compounds in polyethylene terephthalate (PET) bottles and their short- and long-term migration into food simulants and soft drink.

Head space (HS)-GC-MS was used to analyze possible migration of volatile compounds from polyethylene terephthalate (PET) bottles for soft drinks, and a total of six compounds were identified. Next, a rapid, simple, and accurate simultaneous method was established using purge-and-trap (PT)-GC-MS, to quantify their amounts in the liquid contents after short- and long-term storage in PET bottles. Starting with brand-new PET bottles, the maximum migration of 2-methyl-1,3-dioxolane into distilled water and 50 % aqueous ethanol after 2 years at 25 °C were 2.3 and 19 ng/mL, respectively. In commercially available bottled mineral water sold inside and outside Japan, we were able to detect 2-methyl-1,3-dioxolane in the same way. While nonanal was also detected in some products, 2-methyl-1,3-dioxolane was confirmed as the main volatile compound. Finally, the human exposure to 2-methyl-1,3-dioxolane was estimated based on the per capita intake of soft drinks in Japan and the migration amount in this study.

[Validation Study on Migration Test for Plastic Food Utensils, Containers, and Packaging].

Migration test of food utensils, containers, and packaging is an important test method for confirming the safety and their compliance to the standards. However, there is little report on inter-laboratory study which was performed to evaluate the entire migration test, including migration operations and quantification. An interlaboratory study was performed participating 22 laboratories using 8 types of model synthetic resin samples containing 10 substances with a wide range of Log Pow values to evaluate the accuracy of the entire migration test. As a result, most of HorRat (r) values met the target criteria (0.3

[Survey of Total Mercury Content in Fishery Products].

The total mercury content in 112 fishery products, purchased from Osaka city during 2013-2018, was measured using a heating vaporization mercury analyzer. The average total mercury content in all tuna processed products was found out to be 0.115 µg/g (median=0.070 µg/g). Notably, albacore tuna exhibited the highest mercury content with an average concentration of 0.301 µg/g (median=0.296 µg/g). The total mercury concentration of the fishery products, except processed tuna and Kezuribushi (comprising shavings of dried and smoked mackerel, sardine, as well as horse mackerel), was generally low (<0.1 µg/g).The provisional tolerable weekly intake (PTWI) for mercury as set by the Joint FAO/WHO Expert Committee on Food Additives is 4.0 µg/kg body weight/week. On an average, for Japanese diet, the total weekly mercury intake from fishery products for a person weighing 50 kg was estimated to be 0.13 µg/kg body weight/week, which was 3.3% of the PTWI. These values indicate that it was not a problem to consume fishery products normally. However, albacore tuna cans have a relatively high total mercury concentration; thus, pregnant women consuming them daily may exceed the tolerable weekly intake of methylmercury (2 µg/kg body weight/week) as set by the Food Safety Commission of Japan.

[Inter-laboratory Study on the Modified Method Assessment for the Determining Methanol Content in Kitchen Detergents].

We modified a method for determining methanol content in detergents used in kitchens. Furthermore, an inter-laboratory study was conducted in 10 laboratories to validate the modified method. In this study, two concentrations of samples were blindly coded. Each laboratory determined the methanol content in each sample according to a protocol. The determined values were statistically analyzed according to an international harmonized guideline. HorRat values were calculated based on the reproducibility relative standard deviation (RSDR) which was estimated from the interlaboratory study, and predicted RSDR calculated from the Horwitz/Thompson equation. The HorRat values of the two samples were 0.8 and 1.8, meeting the performance criteria of less than 2 set by the Codex Alimentarius for analytical method approval. These results confirm that this modified analytical method shows good performance as an analytical method for determining methanol content in kitchen detergents.

Propensity-Matched Analysis of the Short-Term Outcome of Robot-Assisted Minimally Invasive Esophagectomy Versus Conventional Thoracoscopic Esophagectomy in Thoracic Esophageal Cancer.

BACKGROUND: In this matched-cohort study, we investigated the short-term outcome of robot-assisted minimally invasive esophagectomy (RAMIE) compared with conventional minimally invasive thoracoscopic esophagectomy (MIE) in esophageal cancer patients. METHODS: One hundred eighty-nine patients with thoracic esophageal cancer scheduled to undergo thoracic esophagectomy between 2020 and 2021 were assigned to either RAMIE or MIE. Then, we retrospectively evaluated the postoperative surgical complications between two groups in a propensity-matched analyzation. RESULTS: Based on the propensity-matched score, 50 patients who underwent RAMIE or MIE were selected. Thoracic surgery time in RAMIE/MIE group were 233.1/173.3 min (p < 0.01), respectively. No significant intergroup differences were observed regarding incisional anastomotic leakage (RAMIE group 4.0% vs. MIE group 6.0%) and pneumonia (RAMIE group 8.0% vs. MIE group 12.0%; p = 0.68). The respective incidences of recurrent laryngeal nerve paralysis were 34.0 and 8.0% in the MIE and RAMIE groups, respectively (p < 0.01). In the matched cohort, no differences were observed between the groups in the success accomplishment of the clinical management pathway (RAMIE group 94.0% vs. MIE group 88.0%). CONCLUSIONS: Although patients who underwent RAMIE had longer operation times, the incidence of recurrent laryngeal nerve paralysis was lower than with MIE. Further study in a prospective multi-institutional setting are required to confirm the superiority of RAMIE compared with MIE.

Operative outcomes and long-term survival of patients undergoing colon interposition after esophagectomy for cancer.

BACKGROUND: The first choice of an esophageal substitute after esophagectomy for cancer is the stomach. However, the colon must be considered for reconstruction in specific situations. The purpose of this study was to clarify the frequency and clinical features of patients who underwent colon interposition in thoracic esophagectomy and to investigate the postoperative complications and survival. METHODS: We conducted a retrospective case-control study in the National Cancer Center Hospital East, Japan. Patients who underwent colon interposition after esophagectomy for cancer between 2010 and 2020 were analyzed. RESULTS: Eighty-eight patients underwent esophagectomy with colon interposition; 53.2% received preoperative treatment and 52.3% underwent thoracoscopic surgery. Clavien-Dindo grade >III postoperative complications occurred in 42% of the patients; anastomotic leakage was the most common complication, occurring in 26.1% of the cases. Univariate analysis of the factors associated with Clavien-Dindo grade III complications.

Outcomes of esophagectomy for patients with esophageal squamous cell carcinoma accompanied by recurrent laryngeal nerve palsy at diagnosis.

BACKGROUND: Hoarseness is one of the classical symptoms in patients with locally advanced thoracic esophageal squamous cell carcinoma (ESCC), and it results from recurrent laryngeal nerve palsy, which is caused by nodal metastasis along the recurrent laryngeal nerve or by main tumors. We reviewed the short-term and long-term results of esophagectomy for patients with locally advanced ESCC and hoarseness at diagnosis. PATIENTS: Patients who initially presented with hoarseness from recurrent laryngeal nerve palsy between 2009 and 2018 and underwent esophagectomy for thoracic ESCC were eligible for this study. Pharyngolaryngectomy or cervical ESCC were exclusionary. RESULTS: A total of 15 patients were eligible, and 14 underwent resection of the recurrent laryngeal nerves. The remaining patient had nerve-sparing surgery. Nine patients (60%) had post-operative complications ≥ Clavien-Dindo class II and, pulmonary complications were most common. Two patients (13%) died in the hospital. The 5-year overall survival rate for all patients was 16%. Age (≤ 65 years), cT1/T2 tumor, and remarkably good response to neoadjuvant treatment were likely related to longer survival; however, these relationships were not statistically significant. CONCLUSIONS: Esophagectomy for ESCC patients who are diagnosed with recurrent laryngeal nerve paralysis at initial presentation could be a treatment option if the patient is relatively young, has a cT1/T2 tumor, or shows a remarkably good response to neoadjuvant treatment. However, clinicians should be aware of the possibility of postoperative pulmonary complications, which were frequently observed with the procedure.

Circulation of fibrous microplastic (microfiber) in sewage and sewage sludge treatment processes.

The fate of microplastics (MPs) in the sewage treatment process has been investigated worldwide, and novel results have been reported; few studies have also clarified the fate of MPs in the sewage sludge treatment process. Although most MPs in sewage are transferred to sludge, some flow back from the sludge treatment process to the sewage treatment process. Therefore, throughout the sewage treatment plant, the removal rate of MPs may increase via a countermeasure during the sludge treatment process. In this study, samples obtained from sewage and sewage sludge treatments were used to degrade organic matter with hydrogen peroxide. Water sample particles were trapped on Ni filters with 20-µm-sized pores, dried at room temperature and then the MPs were detected and identified by FTIR microscopy. Note that sludge samples were treated with hydrogen peroxide and separated by specific gravity using NaI solution. The concentration of MPs per unit volume was then calculated and the MPs load was estimated using flow rates of water and sludge. Subsequently, we clarified the fate of MPs with sizes of 20 µm or greater in a sewage treatment plant. When the MPs load in the influent sewage is 100%, 12% of the MPs were found to return to the sewage treatment process via the sidestream of the sludge treatment process. Per this observation, it was made evident that MPs are in fact circulating throughout the sewage and sludge treatment processes. MPs in the sidestream mainly consisted of the effluent from the sludge concentration process, and most MPs were thought to be fibrous polyethylene terephthalate (fibrous MPs, i.e. microfibers [MFs]). The results show that MFs circulate throughout the sewage and sludge treatment processes, and for effectively increasing the removal rate of MPs, the removal of MFs proves correspondingly effective during the sludge treatment process.

Determination of formaldehyde and acetaldehyde levels in poly(ethylene terephthalate) (PET) bottled mineral water using a simple and rapid analytical method.

A simple and rapid analytical method was developed for the determination of formaldehyde (FA) and acetaldehyde (AA) contents in water. FA and AA were derivatized by 2,4-dinitrophenylhydrazine in an LC vial for 20 min at room temperature, about 25 °C, and analyzed using LC-MS/MS. The calibration curve exhibited excellent linearity for FA and AA concentrations of 2-150 ng/mL. Recovery tests using ultra-pure water and commercially available PET-bottled mineral water samples showed good trueness and precision. We determined the FA and AA contents in 105 PET-bottled mineral water samples on the Japanese market using this method. FA was detected in 61% of the samples at levels from 2.6 to 31.4 ng/mL, while AA was detected in 68% at levels from 5.3 to 143.5 ng/mL. These results demonstrate that the concentrations of FA and AA in PET-bottled mineral water on the Japanese market have not changed significantly over the last decade.

[Headspace GC/MS Analysis of Residual Solvents in Laminated Films Used for Food Packaging].

Multilayer laminated films may contain organic solvents derived from adhesives, printing inks and so on. A headspace-GC/MS analysis method for the simultaneous determination of 30 substances such as toluene, xylene, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, methanol, ethanol, was developed. A N,N-dimethyl formamide solution containing an internal standard substance was added to the sample. After leaving overnight at room temperature, the headspace gas was analyzed by GC/MS. This method was applicable to a laminate film made of various materials. The organic solvents such as toluene, ethyl acetate, and heptane were detected from 6 out of 42 food packaging bags made from laminated film on Japanese market using this method.

[Interlaboratory Study on Evaporation Residue Test for Food Contact Products (Report 1)].

An interlaboratory study was performed to evaluate the equivalence between an official method and a modified method of evaporation residue test using three food-simulating solvents (water, 4% acetic acid and 20% ethanol), based on the Japanese Food Sanitation Law for food contact products. Twenty-three laboratories participated, and tested the evaporation residues of nine test solutions as blind duplicates. For evaporation, a water bath was used in the official method, and a hot plate in the modified method. In most laboratories, the test solutions were heated until just prior to evaporation to dryness, and then allowed to dry under residual heat. Statistical analysis revealed that there was no significant difference between the two methods, regardless of the heating equipment used. Accordingly, the modified method provides performance equal to the official method, and is available as an alternative method.

[Interlaboratory Study on Evaporation Residue Test for Food Contact Products (Report 2)].

An interlaboratory study was performed to evaluate the equivalence between an official method and a modified method of evaporation residue test using heptane as a food-simulating solvent for oily or fatty foods, based on the Japanese Food Sanitation Law for food contact products. Twenty-three laboratories participated, and tested the evaporation residues of nine test solutions as blind duplicates. In the official method, heating for evaporation was done with a water bath. In the modified method, a hot plate was used for evaporation, and/or a vacuum concentration procedure was skipped. In most laboratories, the test solutions were heated until just prior to dryness, and then allowed to dry under residual heat. Statistical analysis revealed that there was no significant difference between the two methods. Accordingly, the modified method provides performance equal to the official method, and is available as an alternative method. Furthermore, an interlaboratory study was performed to evaluate and compare two leaching solutions (95% ethanol and isooctane) used as food-simulating solvents for oily or fatty foods in the EU. The results demonstrated that there was no significant difference between heptane and these two leaching solutions.

Interlaboratory Study on Caprolactam Test for Food-Contact Nylon Products.

The Japanese Food Sanitation Law sets a limit on the migration level of caprolactam for food-contacting nylon products. Here, we carried out an interlaboratory study in twenty laboratories to evaluate the performance of the official GC-FID test method and a GC-MS method as an alternative test method to the official method. Each laboratory quantified caprolactam in three test solutions in 20% ethanol as blind duplicates using GC-FID or GC-MS. The official method (GC-FID with absolute calibration) gave trueness, repeatability (RSDr) and reproducibility (RSDr) values of 96-97%, 3.3-5.4% and 4.0-6.7%, respectively. These values met the target criteria (trueness: 80-110%, RSDr: 10%, RSDr: 25%). The performance of the method was further improved by the introduction of heptalactam as an internal standard. As for GC-MS method, some values of the RSDr exceeded 10% when absolute calibration was used. However, when an internal standard was introduced, the trueness, RSDr and RSDr of GC-MS method were all acceptable at 94-96%, 2.0-4.4% and 7.0-9.4%, respectively. Therefore, GC-MS with an internal standard is available as an alternative test method to the official method.

HPLC Analysis of Colorants Migrated from Children's Modeling Clays.

A method using high-performance liquid chromatograph (HPLC) was developed for the identification of colorants migrated from colored modeling clays, which are popular toys for children. Twelve permitted dyes and 25 non-permitted dyes were analyzed in 20 clays (10 wheat clays, 2 rice clays, 2 corn clays, 3 paper clays and 3 resin clays). As a result, 13 products which were labeled for children's use (under 6 years old) met the specifications of the Japanese Food Sanitation Law, while non-permitted colorants were eluted from 2 products. In additon, unknown colorants were eluted from 3 products for people over 6 years old, although these are not covered by the Japanese regulation. It was suggested that some type of clays contained pigments, which are generally used in printing ink and plastics.

Interlaboratory Study on Volatiles Test for Food-Contacting Polystyrene Products.

Using polystyrene, acrylonitrile-styrene resin and acrylonitrile-butadiene-styrene resin pellets as samples, an interlaboratory study was performed to evaluate the volatiles test method, based on the specifications described in the Japanese Food Sanitation Law for food-contacting polystyrene products. The study was conducted with the participation of twenty-one laboratories. Each laboratory quantified the contents of styrene, toluene, ethylbenzene, isopropylbenzene and propylbenzene in three test pellets using GC-FID, GC-MS or headspace-GC-FID. Statistical analysis revealed that the repeatability (RSDr) and reproducibility (RSDr) were 1.0-2.6 and 2.5-5.5% for the GC-FID method. The values of the performance parameters fulfilled the requirements (RSDr: 10%, RSDr: 25%), and the performance is sufficient for specifications testing. The RSDr and RSDr of results obtained using the GC-MS and HS-GC methods were 1.4-7.8 and 4.9-13%(GC-MS), and 2.0-2.6 and 3.3-6.9%(HS-GC-FID), respectively. The quantified levels were similar to those obtained with GC-FID. The study suggests that the GC-MS and HS-GC methods can be employed as alternative methods to the GC-FID method.

Contents of Ag and other metals in food-contact plastics with nanosilver or Ag ion and their migration into food simulants.

Six nanosilver-labelled products and five silver ion (Ag(+))-labelled products were investigated to measure the migration of Ag from food-contact plastics, including nanosilver into various food simulants. The products were obtained in Japanese markets in 2012. Zinc (Zn), another major antimicrobial agent, and three harmful metals, cadmium (Cd), lead (Pb) and arsenic (As), were also examined. Ag and Zn were detected in all six nanosilver products at concentrations of 21-200 and 8.4-140 mg kg(-1), respectively. These metals were also detected in all five Ag(+) products at the same level as nanosilver products. Cd, Pb and As were not detected in any sample. Migrations of Ag and Zn were highest in 4% acetic acid, but also observed in water and 20% ethanol. Big differences were not observed in the migration ratio between nanosilver products and Ag(+) products. The ultrafiltration experiments suggested that the Ag that migrated from nanosilver products into 4% acetic acid was in its ionic form, while that into water and 20% ethanol was in its nanoparticle form.

Development and Validation of Simultaneous Analysis of Minerals and Toxic Elements in Foods by ICP-MS.

We have developed and validated an inductively coupled plasma-mass spectrometry (ICP-MS) method for the simultaneous analysis of minerals and toxic elements in foods. Food samples were digested by microwave irradiation to prepare solutions for measurement by ICP-MS. Optimal gas mode and internal standard for each element were selected as appropriate. The method was validated for eighteen elements in total using three certified standard reference materials, namely, Typical Japanese Diet, Rice Flour-Unpolished and Infant/Adult Nutritional Formula, according to the guidelines of the Ministry of Health, Labour and Welfare of Japan. The trueness and precision of the method were all within the acceptable limits, except for Na in Rice Flour-Unpolished.

[Validation Study on Headspace-GC Analytical Method for Residual Volatile Substances in Food Contact Polystyrene and Its Application for Surveillance (1998-2014)].

A headspace-GC analysis method for the determination of residual volatile substances (styrene, toluene, ethylbenzene, isopropylbenzene and propylbenzene) in food contact polystyrene (PS) was evaluated. Ten PS products were analyzed by this headspace-GC method and the Japanese official method, and the values obtained were almost equal. The performance of the method was evaluated, and the trueness, repeatability and reproducibility were 100.4-102.8%, 3.7-6.3% and 6.0-11.1%, respectively. The values of the performance parameters of the headspace-GC method fulfilled the requirements, and this method was confirmed to be extremely precise. Moreover, contamination of the GC equipment was minimized. The residual volatile substances in 58 PS products were surveyed with this method. All products met the specifications defined in the Japanese Food Sanitation Law, and no relationship was found between volatile substances and the sampling year or country of origin.

[Interlaboratory Study on Zinc Test for Food-Contact Rubber Products].

Using six kinds of zinc solution in water and 4% acetic acid as samples, an interlaboratory study was performed to evaluate a zinc (Zn) test method for food-contact rubber products, based on the Japanese Food Sanitation Law. Eighteen laboratories participated, and quantified Zn in six test solutions as blind duplicates using flame atomic absorption spectrometry, induced coupled plasma-optical emission spectrometry or induced coupled plasma-mass spectrometry. Statistical analysis revealed that the trueness, repeatability (RSDr) and reproducibility (RSDr) were 97-103%, 0.7-4.9% and 1.7-8.9% by all measuring methods. The values of the performance parameter fulfilled the target value (trueness: 80-110%, RSDr: 10%, RSDr: 25%). The performance of these methods is sufficient for testing the adherence of samples to the specifications.

[Interlaboratory study on migration test of antimony and germanium for food-contact polyethylene terephthalate].

An interlaboratory study was performed to evaluate a migration test method of antimony (Sb) and germanium (Ge), based on the Japanese Food Sanitation Law for food- contact polyethylene terephthalate. Eighteen laboratories participated, and quantified Sb and Ge in three test solutions as blind duplicates using graphite furnace atomic absorption spectrometry (GF-AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES) or induced coupled plasma-mass spectrometry (ICP-MS). Statistical analysis revealed that the trueness, repeatability and reproducibility were 98-107%, 1.7-7.5% and 2.0-18.8% by using GF-AAS and ICP-OES. The performance of these methods is sufficient for testing the specifications. The performance parameters of ICP-MS were 99-106%, 0.7-2.2% and 2.2-10.5%, respectively. ICP-MS is available as an alternative measuring method. However, in some laboratories, the quantitative values of Sb were higher than the addition levels. We found that Sb in working solutions is absorbed on glass vessels. Careful control of concentration in working solutions is required for Sb analysis.