Campylobacter Cross‐Contamination of Chicken Products at an Abattoir

Consumption of raw or undercooked poultry products contaminated with Campylobacter has been identified as a risk factor for human campylobacteriosis. We determined whether slaughtering of Campylobacter‐positive flocks was associated with contamination of chicken products derived from Campylobacter‐negative flocks slaughtered at the same abattoir. The presence of Campylobacter was investigated in 22 broiler farms 1 week prior to slaughter and in one abattoir on nine separate slaughter days. A total of 600 bulk packed chicken products were tested, with 198 (33.0%) of the products found to be Campylobacter positive. Of the 350 chicken products originating from Campylobacter‐positive flocks, 180 (51.1%) were contaminated with the bacteria. In contrast, only 18 (7.2%) of 250 chicken products derived from Campylobacter‐negative flocks were contaminated. In 14 of these 18 products, the Campylobacter isolates were identical to isolates obtained from the flock slaughtered immediately prior to the Campylobacter‐negative flock. Notably, on 4/6 slaughter days, Campylobacter‐negative flocks were slaughtered prior to the positive flocks, and Campylobacter was absent from all chicken products originating from the negative flocks. These results suggest that implementation of logistic slaughter (where Campylobacter‐negative flocks are slaughter first) significantly decreases the prevalence of Campylobacter‐positive chicken products.     

Risk factors for Campylobacter colonization in broiler flocks in Japan

The present study was conducted to estimate the prevalence of and to identify the risk factors for Campylobacter colonization in broiler flocks in Japan. Campylobacter colonization status in flock was evaluated by culturing pooled caecal excrement from 124 broiler flocks. Potential exposure to risk factors was evaluated with a questionnaire for the broiler producers. Odds ratios (ORs) were calculated using a multivariable logistic regression analysis. The prevalence of Campylobacter-positive flocks was 43.5% (upper and lower limits of 95% confidence interval (CI(95%) ): 34.8, 52.3). Multivariable logistic regression model identified two variables as risk factors for Campylobacter colonization. The ORs of Campylobacter colonization were higher in flocks in western Japan (OR=2.68; CI(95%) : 1.04, 6.91) than in eastern Japan, and in flocks supplied with undisinfected drinking water (OR=7.41; CI(95%) : 3.11, 17.66) than in those supplied with disinfected drinking water. These findings indicate that water may play an important role in Campylobacter colonization in broiler flocks in Japan and the use of disinfected water may reduce the risk of Campylobacter colonization.     

Prevalence and antimicrobial susceptibility of Campylobacter in broiler flocks in Japan

Campylobacter was isolated from 67 (47.2%) of 142 broiler flocks between September 2009 and February 2010. The prevalence of Campylobacter in broiler flocks was significantly lower during January and February than it was from September to December. Campylobacter colonization was more common in flocks that were not provided with a disinfected water supply, which was consistent with the findings of a previous study. The prevalence of antimicrobial drug‐resistant Campylobacter spp. was investigated, and the minimum inhibitory concentrations of eight antimicrobial agents were determined for 122 Campylobacter jejuni isolates and 46 Campylobacter coli isolates from broiler flocks between 2007 and 2010. In this study, 29.5% (36/122) of C. jejuni isolates and 41.3% (19/46) of C. coli isolates were resistant to enrofloxacin (ERFX), whereas all isolates were susceptible to erythromycin. Furthermore, the ERFX‐resistant isolates were tested for susceptibility to other classes of antimicrobial agents, and 55.6% (20/36) of ERFX‐resistant C. jejuni isolates and 47.4% (9/19) of ERFX‐resistant C. coli isolates were resistant to at least one of aminobenzyl penicillin, dihydrostreptomycin and oxytetracycline. To avoid an impact of antimicrobial drug‐resistant Campylobacter spp. on the efficacy of antimicrobial treatment for human campylobacteriosis, prudent use of antimicrobial agents is a requisite. The use of antimicrobial agents should be accompanied by various approaches such as prevention of Campylobacter colonization in broiler flocks with the aim of lowering the occurrence of Campylobacter infection in humans.     

Mechanism of visceral fat reduction in Tsumura Suzuki obese, diabetes (TSOD) mice orally administered β-cryptoxanthin from Satsuma mandarin oranges (Citrus unshiu Marc)

The carotenoid β-cryptoxanthin (β-CRX) is abundant in Satsuma mandarins (Citrus unshiu Marc). Several studies have shown a relationship between Satsuma mandarin consumption and a low risk of several diseases, for example, diabetes, gout, and hypertension, suggesting β-CRX involvement in disease prevention. We investigated the effect of β-CRX on mildly obese males. β-CRX administration reduced visceral adipose tissue, body weight, and abdominal circumference. However, the detailed mechanism by which β-CRX mediates these changes remains unknown. To identify this mechanism, we used an obese model mouse (TSOD). Oral β-CRX administration repressed body weight, abdominal adipose tissue weight, and serum lipid concentrations in TSOD; these results are identical to previous human trial results. β-CRX administration significantly repressed adipocyte hypertrophy. Gene expression analysis strongly indicated that β-CRX can alter cytokine secretion and cell proliferation. These results suggest that β-CRX derived from Satsuma mandarins can help prevent obesity by repressing hypertrophy of abdominal adipocytes.     

Prevalence and characterization of Shiga toxin-producing Escherichia coli O157 and O26 in beef farms

Rectal content grab samples were collected from 2436 beef cattle reared on 406 beef farms in Japan between November 2007 and March 2008. STEC strains O157 and O26 were isolated from 110 (27.1%) and 7 (1.7%) farms, respectively. Farms that tested positive for STEC O157 were located in 35 out of all 47 Japanese prefectures. This indicates that STEC O157 strains are widespread on beef farms nationwide. Of the 2436 tested beef cattle, 218 (8.9%) and 10 (0.4%) had STEC strains O157 and O26 in the rectal content, respectively. The most common Shiga toxin genes detected in the isolated STEC O157 strains were: stx(2c) alone (32.1%), stx(2)/stx(2c) (27.2%), and stx(1)/stx(2) (21.8%). Almost all of the STEC O157 and STEC O26 strains expressed Shiga toxins (Stx). Most of the STEC O157 and STEC O26 strains possessed eaeA and EHEC-hlyA. These results strongly suggest that STEC strains O157 and O26 from beef cattle would be pathogenic to humans. Therefore, it is important to reduce STEC strains O157 and O26 in beef cattle in order to prevent foodborne disease caused by STEC. The presence of dogs and/or cats on a farm was significantly (P=0.02) associated with the prevalence of STEC O157. More research is needed to clarify the role of dogs and cats.     

Differential scanning calorimetric analysis of the lignin-carbohydrate complex degraded by wood-rotting fungi

Differential scanning calorimetric (DSC) analysis was applied to the lignin-carbohydrate complex (LCC) fractions degraded by the wood-rotting fungiTyromyces palustris andCoriolus versicolor. Based on changes of the thermogram, it is assumed that the brown-rot fungusT. palustris split the hemicellulose fragment from the LCC during incubation. On the other hand, in the case of the white-rot fungusC. versicolor, the peak temperature of the LCC fraction became higher and then lower, indicating that this fungus first degraded the hemicellulose portion and then decomposed the lignin polymer. Furthermore, the appearance of a lignin-rich fraction was found in the fraction fromC. versicolor, which was not determined by gel-permeation chromatographic analysis. These results demonstrated that DSC analysis can be used to analyze the decay mechanism of solid lignocellulosic samples.Part of this report was presented at the 41st Lignin Symposium, Nagoya, October 1996     

Chemical characteristics of surfaces of hardwood and softwood deteriorated by weathering

The factors that cause weather-induced deterioration of wood surfaces were determined by chemical and spectroscopic analyses. Albizzia (Paraserianthes falcata Becker.) and sugi (Cryptomeria japonica D. Don) were exposed to two temperate conditions of natural weathering with and without rainfall and to accelerated conditions of artificial weathering coupled with ultraviolet (UV) light irradiation and water flashing. Infrared spectroscopic analysis showed that the oxidative reaction of lignin was observed under all conditions of weathering for both wood species. However, a marked decrease in lignin and hemicellulose content were recognized when albizzia woods were exposed to weathering with water. Lignin content in the softwood sugi did not decrease as much as in albizzia even in the presence of water, but the modification of lignin macromolecules was assumed to be accelerated by water, as seen by electron spin resonance spectroscopy. These results showed that the presence of water promotes the weathering deterioration of wood under UV irradiation.