Michael Hutchison

Presence of Salmonella in the red meat abattoir lairage after routine cleansing and disinfection and on carcasses.

Foodborne pathogens, such as Salmonella, may remain in abattoir lairages after cleansing and pose a risk of transfer and contamination from one processing day to the next. These organisms may be transferred to the outer surface of animals held in lairage facilities, and the skin or hide may be a significant source of microbial contamination on the red meat carcasses subsequently produced. Sponge samples were taken from various sites in the lairage (n = 556), and single-pass sponge samples were taken from one side of red meat carcasses (n = 1,050) at five commercial abattoirs in Southwest England and tested for the presence of Salmonella. Of these, 6.5% of lairage samples were positive, containing estimated numbers of up to 10(4) Salmonella organisms per sampled area (50 by 50 cm). Salmonella was found on 9.6% of 240 lamb carcasses, 12.7% of 330 beef carcasses, 31% of 70 pig carcasses, 20% of 80 calf carcasses younger than 14 days of age, and none of 330 cull cow and bull carcasses. Subtyping divided the 137 isolates into seven serogroups and three pulsed-field gel electrophoresis clusters, and sensitivity testing against a bank of 16 antimicrobials indicated that 47 isolates had resistance to one or more antimicrobial agents. These results indicate that Salmonella contamination can persist in the lairage environment from one processing day to the next and that Salmonella is present on red meat carcasses, although the implications of residual lairage contamination on carcass meat microbiology are not clear from this study. Abattoir owners should take steps to reduce the level of contamination in their premises to prevent contamination from being carried over from one processing day to the next.

The biosynthesis of kaurenolide diterpenoids by gibberella fujikuroi

Abstract The biosynthesis of 7β-hydroxy- and 7β,18-dihydroxy-kaurenolides from ent -kaur-16-en-19-oic acid has been investigated by incubating unlabelled

An assessment of sampling methods and microbiological hygiene indicators for process verification in poultry slaughterhouses

Studies to determine the appropriateness of the use of populations of indicator bacteria on poultry carcasses for process verification were undertaken in commercial slaughterhouses. Samples were collected from neck skin by excision or from whole carcass rinses and were examined for a range of presumptive process hygiene indicator bacteria. Coefficients of variation were calculated for each bacterial indicator and were significantly lower in excised samples, indicating more reproducible bacterial recovery by this sampling method. Total viable counts of aerobic bacteria, Enterobacteriaceae, and Pseudomonas in samples collected by excision had the lowest coefficients of variation when compared with other indicators and were therefore used for further study. The uncertainties associated with the quantification of each bacterial indicator were calculated and were lowest overall for total viable counts of aerobic bacteria. In general, uncertainty was higher for lower bacterial numbers. Results of microbiological testing on pooled excised neck skin samples were not significantly different from the mean of individually analyzed samples. Bacterial numbers increased by 1 log unit when cultures were stored under chilled conditions typical of those used for transporting samples to external laboratories, but the increases were not significant for Pseudomonas and aerobic bacteria when storage time was less than 17 h. Weak relationships were identified between bacterial indicator numbers and duration of processing, although cleanliness of the processing environment diminished visibly during this time. In the plants visited for this study, there was a poor relationship between presumptive bacterial indicator numbers and process hygiene. Consequently, bacterial analyses for process verification purposes may be of limited value.

Gibberellins in seeds of Helianthus annuus

Abstract Fourteen gibberellins (GAs) have been identified in seeds of Helianthus annuus . They comprise the previously known GA 1 , GA 4 , GA 19 , GA 20 , and GA 45 , and nine new 15β-hydroxyGAs. Of the new GAs, 15β-hydroxyGA 20 and 15β-hydroxyGA 1 have been previously synthesized chemically from GA 3 and are now assigned the numbers GA 67 and GA 72 . The structures of 15β-hydroxyGA 15 , 15β-hydroxyGA 24 , and 15β-hydroxyGA 25 were established by their formation from the incubation of ent -15β-hydroxykaur-16-en-19-oic acid with cultures of Gibberella fujikuroi , mutant B1-41a; these new GAs have been respectively assigned the numbers, GA 64 , GA 65 and GA 66 . The remaining four GAs have been tentatively assigned the structures, 15β-hydroxyGA 17 , 15β-hydroxyGA 19 , 15β-hydroxyGA 44 and 15β-hydroxyGA 53 on the basis of the mass spectra of their MeTMSi derivatives. Abscisic acid, trans -abscisic acid, dihydrophaseic acid, dioxindole-3-acetic acid, ent -7α,16α,17-trihydroxy-16αH-kauranoic acid and ent -7α,16β,17-trihydroxy-and ent -6α,7α,16β,17-tetrahydroxy-16βH-kauranoic acids have also been detected in seeds of Helianthus annuus by capillary GC-MS. From the incubation of ent -15α-hydroxykaur-16-en-19-oic acid with Gibberella fujikuroi , mutant B1-41a, ent -7α,15α-dihydroxykaur-16-en-19-oic acid and 7β,15β-dihydroxykaurenolide have been isolated.

Microbiological conversion of 12-oxygenated and other derivatives of ent-kaur-16-en-19-oic acid by Gibberella Fujikuroi, mutant B1-41a

Abstract The metabolism of several ring C and D-functionalized ent-kaur-16-en-19-oic acids by cultures of Gibberella fujikuroi, mutant B1-41a, to the corresponding derivatives of the normal fungal gibberellins (GAs) and ent-kaurenoids is described. A range of 12α- and 12β-hydroxyGAs and ent-kaurenoids are characterized by their mass spectra and GC Kovats retention indices. The mass spectral and GC data are used to identify the 12α-hydroxy derivatives of GA12, GA14, GA37 and GA4 (GA58), and of the 12β-hydroxy derivatives of ent-7α-hydroxy- and ent-6α, 7α-dihydroxykaurenoic acids, in seeds of Cucurbita maxima. Similarly the metabolites of GA9, formed in seeds of Pisum sativum and cultures of G.fujikuroi, mutant B1-41a, are identified as 12α-hydroxyGA9. ent-11β-Hydroxy- and ent-11-oxo-kaurenoic acids are metabolized by the fungus to the corresponding 11-oxygenated derivatives of the normal fungal ent-kaurenoids and some C20-GAs; no 11-oxygenated C19-GAs are formed. Grandiflorenic acid, 11β-hydroxygrandiflorenic acid, attractyligen and ent-15β-hydroxykaurenoic acid are metabolized to unidentified products.

Carbon-13 nuclear magnetic resonance spectra of eighteen derivatives of ent-kaur-16-en-19-oic acid

The 13C n.m.r. spectra of eighteen derivatives of ent-kaur-16-en-19-oic acid are recorded and the additivity of substituent effects is investigated. Application of these additive effects to the prediction of the 13C-shifts in new polysubstituted derivatives is assessed.

Measurement of Campylobacter Numbers on Carcasses in British Poultry Slaughterhouses

An assessment of the proposed new International Organization for Standardization quantitative method for Campylobacter was undertaken on poultry carcass samples collected after the chilling phase of processing. Using a critical differences method, we determined the uncertainty associated with log-transformed Campylobacter numbers by dual analyses of 346 samples collected from 22 processing plants located throughout the United Kingdom. Overall, using log-transformed Campylobacter numbers that ranged between -1 and 5 log, we calculated the expanded measurement of uncertainty (EMU) to be 3.889 for the new method. The EMU changed when ranges of bacterial numbers were grouped for analyses. For low numbers of Campylobacter (< 1 log), the EMU was calculated to be 5.622. There was less measurement error with higher bacterial numbers because the EMU was found to be 0.612 for samples containing Campylobacter numbers of 3 log or above. The draft method was used to measure numbers of Campylobacters on poultry carcasses collected from 18 United Kingdom processing plants in summer and winter. Numbers were significantly lower in winter. We conclude that, although the new method is adequate at quantifying high numbers of Campylobacter on poultry carcasses, further development is required to improve the measurement of small numbers of this causative agent of foodborne illness.

Implementation of Compulsory Hazard Analysis Critical Control Point System and Its Effect on Concentrations of Carcass and Environmental Surface Bacterial Indicators in United Kingdom Red Meat Slaughterhouses

Statutory microbiological test results were collected from British meat plants over a 4-year period from June 2002 to May 2006. A total of 49,074 carcass test results from 19,409 cattle, 14,706 sheep, and 14,959 pig swabs and 95,179 environmental test results from surface swabs were obtained. These test results were donated by 94 slaughterhouses, which process about two thirds of the British national annual throughput of cattle, sheep, and pig carcasses. The data were collectively analyzed to determine any historical trends for numbers of total aerobes and Enterobacteriaceae. Significant reductions were observed in the numbers of indicator organisms on carcasses for all three species between 2002 and 2006. Reductions were also observed for numbers of aerobes on environmental and food contact surfaces. There were seasonal differences in bacterial numbers isolated from carcasses. Cattle and sheep carcasses had significantly higher numbers of total aerobes and Enterobacteriaceae in late summer and early autumn, whereas numbers of total aerobes on pig carcasses were higher in winter. Bacterial numbers on environmental surfaces were not influenced by the month that the swab samples were collected. Possible reasons for the observed reductions in bacterial numbers on carcasses and surfaces and the implications for carcass testing for process control purposes are discussed.

1β-Hydroxygibberellin A5. Preparation and comparison with gibberellin A3

The preparation of 1β-hydroxygibberellin A5 from gibberellin A3 is described. Unlike its naturally occurring allylic isomer gibberellin A3,1β-hydroxygibberellin A5 is stable to aqueous alkali and acid-catalysed aromatisation of ring A does not occur. Reasons for these differences, and for the hitherto unreported 3-epimerisation of gibberellin A3 by base, are discussed in terms of O-alkyl fission of the lactone bridge.

Partial syntheses of gibberellins A45 and A63

The structures of the higher plant 15β-hydroxy-C19-gibberellins, GA45 and GA63, have been established by rational syntheses from gibberellins A9 and A4 respectively.