Food Hygiene and Safety Science最新文献

Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli) can colonize the gastrointestinal tracts of broilers, and poultry meat is contaminated with these organisms during slaughter in poultry processing plants. We investigated the relationship between Campylobacter counts in cecal contents of broilers and those in chicken meat at eight chicken processing plants. Ceca and their breast products derived from broilers from 51 flocks were collected. Campylobacter were isolated from cecal contents of 40 (78.4%) flocks. The average number of Campylobacter in the ceca of the Campylobacter-positive flocks was 7.6 1og₁₀ CFU/g. Of 51 chicken breast products, 35 (68.6%) were contaminated with Campylobacter and the average number of Campylobacter was 1.7 1og₁₀ CFU/g. All the Campylobacter-positive products were derived from Campylobacter-positive flocks. The results of this study indicate that there is a weak positive correlation (R=0.37) between the number of Campylobacter in the ceca of broiler flocks and the number of Campylobacter in chicken meat. Of the 14 products with C. jejuni/C. coli counts of 2.0 log₁₀ CFU/g or more, nine (64.2%) were from groups with high Campylobacter (≥ 8.4 log₁₀ CFU/g) in the ceca. The Campylobacter prevalence of products from chicken flocks with C. jejuni/C. coli counts of 6.2 log₁₀ CFU/g or less in the cecal contents have a C. jejuni/C coli contamination rate of 50% (3/6) with a maximum Campylobacter count of 1.4 log₁₀ CFU/g.

Histamine (Him), tyramine (Tyr), putrescine (Put), and cadaverine (Cad), known as nonvolatile amines (NVA), have been identified as particular public health risks. We analyzed 102 samples of 64 agricultural products in Japan. Him was present in 12 products, with eggplant, spinach, and tomatoes containing higher concentrations than other agricultural products. Tyr was present in 29 products, the concentration of which peaked at 132 μg/g in hanabiratake mushrooms. Therefore, we think that patients taking monoamine oxidase inhibitors may need to exercise caution when consuming products containing such high Tyr concentrations. Put was present in many items, especially in solanaceous vegetables, with concentrations of 100 μg/g or more in shishito pepper, sweet pepper and sweet corn, while Cad was present in 15 products, peaking at 3.2 μg/g in sweet pepper. The combination of these foods with foods containing high Him concentrations may lead to allergy-like symptoms.

The study aimed to evaluate the effect of peracetic acid formulation (PAA) in the cut salads as a model food with different treatment conditions and observed their effect on the shelf life. This study revealed that at 80 ppm PAA, the standard for use on vegetables, showed a temporary and weak bactericidal effect. Additionally, there was no improvement in the shelf life of the cut salad. In contrast, PAA treatment at 240 ppm significantly reduced and suppressed the growth of hygiene indicator bacteria for 7 days. Moreover, no injured bacteria were produced due to proper sterilization. Based on these findings, it is believed that 240 ppm of PAA is suitable for washing cut salads and effective to improve their shelf life.

LC-MS/MS was used to develop a qualitative analytical method for milk, egg, buckwheat, and peanut allergens. The measurement conditions and extraction and trypsin digestion process for protein pretreatment were optimized. A sample spiked with each allergen was analyzed to evaluate the performance of the analytical method, including the extraction process. Repeatability and intralaboratory precision met the target values for all allergens, confirming the stability of the analytical method. Furthermore, the S/N ratio, retention time, and peptide ratio demonstrated the usefulness of the method as a qualitative test. Moreover, for milk and egg allergens, the equivalence of the quantitative values calculated using the developed method to those of ELISA was confirmed; however, this equivalence could not be confirmed for commercially available processed foods and some quality control samples. For buckwheat and peanut allergens, the equivalence of the quantitative values to those of ELISA could not be confirmed in the spiked sample. These findings demonstrate that this analytical method is useful as a rapid and simple qualitative test. It is also an excellent alternative to ELISA as it produces less waste and reduces environmental burden.

Standard curves are used to estimate the concentration of a target substance in food samples and the curves are generally made with the least square method. The least square method is allowed to apply only under the condition that the measurements follow the normal distribution with a constant variance. Actually, however, it is thought that as the measurements of samples are higher, the scattering of the measurements would be also larger. In this study, thus, the effect of the scattering of measured values of samples on the concentration estimation was studied with two normal distribution models with a constant variance and a variance changing to measured values. Measurement data analyzed here were random samples from the normal distributions with various variance. As a result, in the case that the concentrations of the target substance and the measurements were linear, the latter model with the changing variance was statistically more appropriate for the data whose scattering increased with it. However, no remarkable differences were observed between the two models in the standard curves and the estimates from those curves for the measurement sets studied. In the case that the concentrations and the measurements were nonlinear being concave downward and upward, the same results were also observed. These results showed that the model with the changing variance would be more appropriate than the one with the constant variance for various measurement data, while both models could also successfully estimate the concentration of unknown samples.

Chloropropanols and related substances have received a great deal of attention in the world. Regulation values have already been established in the EU for infant formula. There are several validated analytical methods for these substances, such as the AOAC official method. However, no analytical official method has been established for infant formula in Japan. In this study, the AOAC official method was improved to a more versatile splitless injection method in order to make it feasible for many laboratories. The results of the validation data for the improved method with optimized injection conditions were as follows. The limit of quantification was 10 μg/kg, the recovery rate ranged from 81.6 to 114.5%, and the intermediate precision ranged from 1.6 to 7.6%. These results were adapt to AOAC and EU requirement and demonstrated the good validity of the improved method.

A method for the determination of two kinds of cyanide, namely cyanide ion and cyanogen chloride, in various mineral waters (MWs) has been developed and validated. MWs are varying in the degree of hardness and carbonation. The results of two carbonated MWs obtained through the validated official method for cyanide analysis in tap water did not meet the criteria of the validation guideline for MW in Japan. Furthermore, in the pH adjustment during pretreatment, some MWs did not reach approximately pH 2.4, the level assumed in tap water quality tests. After five-fold dilution of the samples with phosphate buffer, the specified pH value of 2.4 was achieved, leading to the improvements in trueness. The validation tests of the method with the additional dilution step showed the trueness from 93.0 to 103.8%, RSDs of repeatability and within-laboratory reproducibility below 3.83% and 4.68%, respectively. These values fulfill the criteria on both analytes. The developed method indicated the potential applicability for accurate determination of cyanide ion and cyanogen chloride in a range of commercially available MW products.

Ovomucoid is a protein found in egg white and is the major cause of egg allergy. We have been conducting studies on chicken eggs that do not contain ovomucoid (ovomucoid-null: ON eggs) as hypoallergenic eggs and confirmed that the gelling, foaming, and emulsifying properties of these eggs are almost similar to those of control (Ct) eggs and that they are suitable for cooking and confectionery. In the present study, we compared the changes in bacterial counts in ON eggs and Ct eggs in shell eggs, liquid whole eggs, and liquid egg whites with added Pseudomonas fluorescens, Salmonella Enteritidis, and Bacillus cereus and found no tendency for bacterial counts to increase more easily in ON eggs than in Ct eggs. We guessed that ovomucoid does not affect the bacteriostatic properties of chicken eggs, and that ON eggs do not increase microbial risk.

This study clarified the relation between thelephoric acid, the coloring molecule of a simple method of identifying Omphalotus japonicus using a beam reagent (5 w/v% potassium hydroxide ethanolic solution), and the color tone of the pileus epidermis and stained area of the stem base. Correlation was found between the shade of the pileus epidermis and stained area of the stem base and the thelephoric acid concentration. Identification methods of two types were used: direct method and extraction method. Results suggest that selecting an appropriate identification method according to the fruiting body condition will improve identification accuracy and conservation of labor.Furthermore, no correlation was found between illudin S, a toxic component of O. japonicus, and thelephoric acid concentration. Therefore, analyzing illudin S as usual is considered necessary when identifying the cause of food poisoning associated with O. japonicus.

A quantitative method for determining resorcylic acid lactones (zeranol, taleranol, zearalanone, and zearalenone) in bovine urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and evaluated for use in the monitoring of Japanese beef exports to the European Union. This method involves the hydrolysis of conjugates by ß-glucuronidase/aryl sulfatase, clean-up with an immunoaffinity cartridge, and analysis using LC-MS/MS. The developed method was evaluated for zeranol, taleranol, zearalanone, and zearalenone in bovine urine at concentrations of 1 and 2 μg/L. The trueness ranged from 92 to 101%, with intra-day precision of <9% and inter-day precision of <13%. No interfering peaks were observed in the chromatogram near the analyte retention times. This analytical method is valuable for monitoring taleranol, zearalanone, and zearalenone in beef exports to the European Union. The proposed method is also applicable for screening whether zeranol was illegally administered or ingested via feed contaminated with Fusarium toxins, particularly in cases in which taleranol was detected.