Use of low dose e-beam irradiation to reduce E. coli O157:H7, non-O157 (VTEC) E. coli and Salmonella viability on meat surfaces

This study determined the extent that irradiation of fresh beef surfaces with an absorbed dose of 1 kGy electron (e-) beam irradiation might reduce the viability of mixtures of O157 and non-O157 verotoxigenic Escherichia coli (VTEC) and Salmonella. These were grouped together based on similar resistances to irradiation and inoculated on beef surfaces (outside flat and inside round, top and bottom muscle cuts), and then e-beam irradiated. Salmonella serovars were most resistant to 1 kGy treatment, showing a reduction of ≤ 1.9 log CFU/g. This treatment reduced the viability of two groups of non-O157 E. coli mixtures by ≤ 4.5 and ≤ 3.9 log CFU/g. Log reductions of ≤ 4.0 log CFU/g were observed for E. coli O157:H7 cocktails. Since under normal processing conditions the levels of these pathogens on beef carcasses would be lower than the lethality caused by the treatment used, irradiation at 1 kGy would be expected to eliminate the hazard represented by VTEC E. coli.     

Effect of electron beam irradiation on quality indicators of peanut butter over a storage period

Electron beam (e-beam) irradiation is an effective non-thermal processing step for the reduction of Salmonella in peanut butter. The objective of this study was to evaluate the effects of e-beam irradiation on quality indicators of peanut butter. Peanut butter samples were exposed to a range of e-beam doses and examined over a 14-day period at 22 °C. Colour analysis (L^∗, a^∗, b^∗), spreadability, peroxide values (PV) and thiobarbituric acid reactive substances test (TBARS) for lipid oxidation were monitored, fatty acid and amino acid profiles were verified and protein degradation was determined by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE). Changes in colour, PV, and TBARS were observed as e-beam dose increased. No significant changes in spreadability were observed (P > 0.05). When applied to peanut butter, e-beam irradiation will produce significant changes in quality indicators; future studies should include sensory evaluation and consumer acceptance studies.     

Optimizing irradiation treatment of shell eggs using simulation

Accurate dose calculation is needed to ensure proper irradiation process control to maintain the freshness of the product. Our objective was to establish the best irradiation treatment for shell eggs taking into account their different components (shell, albumen, yolk). Computer tomography (CT) data were used to generate a 3-D geometry to simulate dose distributions within 1 egg using a radiation transport code (MCNP5). Radiation energies used for simulation were 10 MeV (high-energy) and 1.35 MeV (low-energy) for electron beam, 5 MeV for X-rays, and 1.25 MeV for a gamma-rays source such as Co-60. Low-energy (surface) e-beam simulation indicated that electrons only penetrate up to the thin albumen (0.6 cm). Because of their irregular shape, shell eggs should be irradiated from the side (rather than from top or bottom) for better dose distribution. For high-energy e-beam simulation, the entire egg was irradiated and the best results were obtained when the egg was irradiated from both sides, showing a dose uniformity ratio (D(max)/D(min)) of 1.42. X- or gamma-ray source simulation from one side only, the dose uniformity ratio was 3.38 and 3.12, respectively. For surface-only irradiation, a low-energy e-beam provides a uniform dose distribution. To irradiate the entire egg, 2-sided high-energy e-beam sources are required for an efficient treatment. Unless the product rotates in front of the source, the dose uniformity ratio for X-ray or gamma ray is not adequate for shell egg treatment for pathogen decontamination purposes. Practical Application: Proper control of irradiation treatment of foods such as shell eggs is critical to ensure pathogen inactivation while maintaining product freshness. Simulation allows for accurate calculation of dose distribution within the egg to further establish the best irradiation scheme.     

Prediction of targeted Salmonella enterica serovar typhimurium inactivation in fresh cut cantaloupe (Cucumis melo L.) using electron beam irradiation

Pathogens internalize in fresh produce. When using e-beam accelerators to treat the produce, it must be designed to ensure that the entrance dose will translate into the effective dose delivered at the interior of the food. The low penetration capacity of e-beam accelerators makes this a difficult task. If dose is non-uniform at different locations within the product, under-or-over-dosage could compromise safety and quality. We calculated the dose required for “targeted” inactivation of S. typhimurium LT2 internalized in fresh cantaloupe flesh using e-beam irradiation. Target inactivation is the estimation of the dose required to inactivate bacteria to the target level at a certain depth in the product. Growth and mobility data were used for simulation of irradiation protocols in a commercial facility (10 MeV e-beam linear accelerator) using radiation theory. Bacterial infestation and internalization into cantaloupe would require more than 1.0 kGy and compensators should be used to reduce the dose required at a certain depth in the produce.     

Effects of electron-beam irradiation on the shelf life, microbial populations and sensory characteristics of summer truffles (Tuber aestivum) packaged under modified atmospheres

The effects of two doses of electron-beam irradiation (1.5 kGy and 2.5 kGy) on the microbial populations (total mesophilic aerobes, Pseudomonas genus, Enterobacteriaceae family, molds and yeasts) and sensory characteristics of Tuber aestivum packaged under modified atmospheres were monitored immediately after treatment, and weekly during 42 days of storage at 4 °C. Treatment with 1.5 and 2.5 kGy reduced the pseudomonads populations by 4.3 and 5.5 logs, respectively. Enterobacteriaceae counts decreased by 5.4 logs with the 1.5 kGy dose and counts below the detection limit (<1.0 log cfu/g) were obtained with the 2.5 kGy dose. Lactic acid bacteria and yeasts were less affected by the ionizing radiation treatments and they became the dominant microbial populations throughout storage with microbial counts up to 7.1 log cfu/g. The carbon dioxide levels inside the packages containing irradiated truffles were lower than those of the non-irradiated ones, suggesting a decrease in the respiration rate of the treated ascocarps. The treatments with 1.5 and 2.5 kGy e-beam did not negatively affect the sensory characteristics of truffles, but a visible superficial yeast growth was detected in truffles irradiated with 1.5 kGy at the end of their shelf life (day 28). Treatment with 2.5 kGy e-beam has prolonged the shelf life to 42 days, compared with 21 days for the untreated samples.     

Campylobacter contamination of broiler caeca and carcasses at the slaughterhouse and correlation with Salmonella contamination

In order to estimate the prevalence of Campylobacter spp. and Salmonella spp. on broiler chicken carcasses and the prevalence of Campylobacter spp. in caeca, 58 French slaughterhouses were investigated in 2008. Enumeration of Campylobacter spp. was also performed in order to study the relation between caeca and carcass contamination. A pool of 10 caeca and one carcass were collected from 425 different batches over a 12-month period in 2008. Salmonella was isolated on 32 carcasses leading to a prevalence of 7.5% ([5.0-10.0]_95%CI). The prevalence of Campylobacter was 77.2% ([73.2-81.2]_95%CI) in caeca and 87.5% ([84.4-90.7]_95%CI) on carcasses. No significant correlation was found between Campylobacter and Salmonella. Positive values of Campylobacter were normally distributed and the average level was 8.05 log₁₀ cfu/g ([7.94-8.16]_95%CI) in caeca and 2.39 cfu/g ([2.30-2.48]_95%CI) on carcasses. A positive correlation (r = 0.59) was found between the mean of Campylobacter in caeca and on carcasses (p < 0.001). Thus, carcasses from batches with Campylobacter-positive caeca had significantly (p < 0.001) higher numbers of Campylobacter per gram than batches with negative caeca. These results show that Campylobacter can be present in both matrices and reduction in caeca could be a possible way to reduce the amount of bacteria on carcasses. Of the 2504 identifications performed, 3 species of Campylobacter (Campylobacter jejuni, Campylobacter coli and Campylobacter lari) were identified. The main species recovered were C. jejuni and C. coli, which were isolated in 55.3% and 44.5% of positive samples, respectively. These two species were equally represented in caeca but C. jejuni was the most frequently isolated on carcasses with 57.1% and 42.5% of positive carcasses for C. jejuni and C. coli, respectively. This study underlines that target a reduction of Campylobacter on final products requires a decrease of contamination in caeca.     

Hot water surface pasteurisation of lamb carcasses: microbial effects and cost-benefit considerations

Although hot water pasteurisation of carcasses is accepted as a general intervention in USA, this is not the case in Europe. The aims of this study were (i) to evaluate the microbiological effects of hot water pasteurisation of lamb carcasses, both after slaughtering and dressing and following subsequent chilling and storage; (ii) to discuss hot water pasteurisation from a public health and cost-benefit perspective; (iii) to discuss the benefits of hot water pasteurisation compared with use of separate meat processing streams for high-risk carcasses; (iv) to evaluate the use of recycled hot water in a hygienic context and in relation to EU regulations; and (v) to consider the technological and sensory aspects of hot water pasteurisation of lamb carcasses. Samples were collected from 420 naturally contaminated lamb carcasses, with 50% of the carcasses (n = 210) subject to hot water pasteurisation at 82 °C for 8 s immediately after slaughter. Surface swab samples from 4500 cm² areas on carcasses were collected at slaughter, after chilling for 24 h, and after chilling for five days. The microbial analyses included Escherichia coli, Enterobacteriaceae, Bacillus cereus, Clostridium perfringens and aerobic plate count (APC). A resuscitation step using Tryptone Soya Agar was included in the microbiological analyses. Hot water pasteurisation significantly reduced the levels of E. coli, Enterobacteriaceae, B. cereus and APC (all P < 0.001). E. coli colony forming unit (CFU) reduction was 99.5%, corresponding to a reduction of 1.85 log CFU per carcass. E. coli was isolated from 66% of control carcasses and from 26% of pasteurised carcasses. After 24 h storage, the reduction in E. coli was increased to 2.02 log, and after five days E. coli could not be isolated from the pasteurised carcasses. These results suggest that surface pasteurisation could be an important and efficient procedure (critical control point) for reducing generic E. coli and thereby shiga toxin-producing E. coli on carcasses, and thus the risk for disease among consumers. The recycled water had acceptable physical and chemical parameters and no spore-forming bacteria were detected. Although some carcass discolouration was observed, after 24 h the colour was acceptable. Our data provide relevant input for some of the data gaps regarding hot water pasteurisation and indicate that replacing the expensive system of separate processing of high-risk carcasses with hot water surface pasteurisation should be considered as a serious option.     

Electron beam and gamma irradiation as feasible conservation technologies for wild Arenaria montana L.: Effects on chemical and antioxidant parameters

Wild plants are widely recognized as high-potential sources of several bioactive compounds. Nevertheless, these natural matrices require effective decontamination steps before they might be considered for different industrial purposes. Irradiation techniques are being progressively acknowledged as feasible conservation methodologies, either for their high decontamination effectiveness, as well as for their innocuousness on most chemical and bioactive parameters of the material to be treated. Arenaria montana L. (Caryophyllaceae) is recognized for its phytochemical richness, having a relevant geographical distribution in the Southern Europe. Herein the effects of irradiation (gamma and electron beam up to 10 kGy) were evaluated by comparing the nutritional, chemical and antioxidant profiles in A. montana extracts. In general, the assayed parameters showed statistically significant variations in response to irradiation treatment. Furthermore, the performed LDA allowed identifying the antioxidant indicators as the most affected parameters in irradiated samples, especially when using the 10 kGy dose and e-beam irradiation.Industrial relevanceWild plants are recognized as high-potential sources of several bioactive compounds. Nevertheless, they require effective decontamination steps before being considered for different industrial purposes. Irradiation techniques are being progressively acknowledged as feasible decontamination methodologies, but several options are available. The present study, using Arenaria montana as a case-study, reports important clues for choosing a specific irradiation type or dose according to the need of maintain a specific chemical or bioactive profile.     

Effect of gamma and electron beam irradiation on the survival of pathogens inoculated into salted, seasoned, and fermented oyster

The objective of this study was to identify the efficacy of gamma and electron beam irradiation of the food-borne pathogens including 3-strain cocktail of Listeria monocytogenes (ATCC 19114, 19115, and 19111), Staphylococcus aureus (ATCC 6538, 25923, and 29213), and Vibrio parahaemolyticus (ATCC 17802, 33844, and 27969) in salted, seasoned, and fermented oyster (oyster Jeotkal, 8% salt), commercially available in the market. Irradiation (0, 0.5, 1, 2, and 5 kGy) significantly reduced the initial microbial level not only immediately after irradiation but also during storage at 10 °C for 4 weeks (P ≤ 0.05). No viable cell was detected at 5 kGy of irradiation at a detection limit of 10¹ CFU/g. Gamma irradiation was more effective than electron beam irradiation, and yielded D₁₀ values of 0.60, 0.71, and 0.29 kGy for L. monocytogenes, S. aureus, and V. parahaemolyticus, and those of electron beam irradiation were 0.69, 0.94, and 0.29 kGy, respectively. V. parahaemolyticus was most sensitive to irradiation and storage among all pathogens tested. Sensory quality was not affected by irradiation treatment. Results suggest that a low dose irradiation can improve the microbial quality and reduce the risk by the food-borne pathogens of oyster Jeotkal, which has limited alternative sterilization methods due to the temperature sensitivity of food products.     

Study of chemical compositions,anti-nutritional contents and digestibility of electron beam irradiated sorghum grains

Effects of electron beam irradiation at doses of 10, 15, 20, 25 and 30 kGy on chemical composition, phytate and tannin contents, and in vivo digestibility of sorghum grain were investigated. Irradiation had no effect (p > 0.05) on chemical compositions. Tannin content was reduced (p < 0.05) by 28%, 30%, 42%, 83% and 86% and phytate content reduced (p < 0.05) by 39%, 49%, 66%, 79% and 90% in electron beam irradiated compared to control, respectively. Irradiation improved (p < 0.05) in vivo digestibilities of dry matter, crude protein, true protein and gross energy. Based upon these results, electron beam irradiation was judged to be a useful processing method for reducing the anti-nutritional compounds and therefore, improving nutritive value of sorghum grain.     

Inactivation kinetics of Escherichia coli by pulsed electron beam

ABSTRACT:  A novel and compact low-energy (keV) high-power pulsed electron beam (e-beam) that utilizes a secondary emission electron gun (SEEG) was designed and constructed. Escherichia coli JM 109 at a concentration of 10⁶ CFU/mL was spread-plated on Luria-Bertani (LB) medium and subjected to the SEEG e-beam. The e-beam was administered as 1 or 5 pulses. The duration of a single pulse was constant at 5 μs, e-beam current density was constant at 25 mA/cm², and e-beam energy varied between 60 and 82.5 keV. Following treatment with the SEEG e-beam, survivors of the irradiated E. coli samples were enumerated by a standard 10-fold dilution and spread-plated. The survivor curves were plotted on logarithmic scale as a function of e-beam dose. The D ₁₀-values were calculated as a negative reciprocal of the slope of the survivor curves. The D ₁₀-values for E. coli inactivated with 1- and 5-pulse SEEG e-beam were 0.0026 and 0.0217 Gy, respectively. These D ₁₀-values were considerably lower than published D ₁₀-values for E. coli inactivated with conventional high-energy continuous e-beam, likely due to shorter exposure time ( t ), greater current density ( J ), and a pulse mode of the SEEG e-beam. The SEEG e-beam showed promising results for microbial inactivation in a nonthermal manner; however, due to low energy of the SEEG e-beam, current applications are limited to surface decontamination. The SEEG e-beam may be an efficient processing step for surface inactivation of food-borne pathogens on ready-to-eat products, including fresh and leafy vegetables.     

A comparison of the effects of E-beam irradiation and heat treatment on the variability of Bacillus cereus inactivation and lag phase duration of surviving cells

The effects of electron beam irradiation and heat treatments on the variability of inactivation of Bacillus cereus spores (CECT 131/ATCC 10876) and of the lag phase of single surviving cells have been studied. In general, dispersion in the number of survivors increased as the stress became more intense. A polynomial relationship was derived between the coefficient of variation of the survivor number and the inactivation achieved. Heat treatments caused wider distributions than irradiation for the same substrate and for a similar degree of microbial inactivation.Increasing the intensity of the inactivation treatment lengthened the lag phase of survivors and increased its variability. Comparison of lag phases of heated and irradiated spores did not show any clear relationship. Heating did not affect the specific growth rate of surviving cells, whereas irradiation lowered the maximum specific growth rate in proportion to the dose applied. These results suggest that the shelf life of irradiated foods is longer than that of heated foods.     

Correlation between astaxanthin amount and a* value in fresh Atlantic salmon (Salmo salar) muscle during different irradiation doses

The amount of astaxanthin and a* value changes in fresh Atlantic salmon light and dark muscle during cold storage was studied for different e-beam doses (0, 1, 1.5, 2 and 3 kGy). Astaxanthin (mg/kg muscle) and a* value decreased with increasing irradiation dose for both fresh light and dark muscle. The level of irradiation dose gave high correlation between a* value and amount of astaxanthin. The reason for the change in colour or decrease in a* value of Atlantic salmon during irradiation could be due to the destruction of astaxanthin. The amount of astaxanthin and a* value of 1 kGy treated salmon fillets were not significantly different (p > 0.05) from that of the control but significantly different (p < 0.05) from other irradiation treatments. The colour (a* value) of salmon muscle was related to the content of astaxanthin, which decreased as irradiation increased. The amount of astaxanthin in light muscle was three to five times greater than dark muscle. This study demonstrated that irradiating salmon fillets at 1 kGy, can be successfully used and leads to no significant change in colour and amount of astaxanthin.     

Campylobacter contamination in broiler carcasses and correlation with slaughterhouses operational hygiene inspection

This study investigates factors associated with Campylobacter contamination of broiler carcasses, using survey data collected from nine Belgian slaughterhouses in 2008 in accordance with a European Union baseline study. Campylobacter were detected in 51.9% (202/389) (95% confidence interval, 46.8%-56.9%) of broiler carcasses. Campylobacter concentration was <10 CFU/g in 49.6% of carcasses, while 20.6% were contaminated with ≥1000 CFU/g. The mean Campylobacter concentration, as calculated by maximum likelihood estimation for left-censored data, was 1.8 log₁₀ CFU/g, with a standard deviation of 1.9 log₁₀ CFU/g. There was statistically significant variation among slaughterhouses in prevalence and concentrations of Campylobacter in their sampled carcasses. Campylobacter prevalence (but not concentrations) was positively associated with increase in broilers age. Both Campylobacter prevalence and concentration were significantly higher in carcasses sampled during June and September (but not in July and August) than carcasses sampled in January. We also investigated the correlation (Spearman’s rank correlation test) between the scores of official control inspections and Campylobacter prevalence for eight out of the nine slaughterhouses. The control inspections were routinely performed by the Belgian Federal Agency for the Safety of the Food Chain, and the concluded inspection scores were used as a general numerical indicator for the status of operational hygiene and quality of management in the slaughterhouses. Ranking of slaughterhouses based on their inspection scores was statistically correlated (Spearman’s correlation coefficient = 0.857) with their ranking based on prevalence of Campylobacter. In the present study we demonstrate how the outcomes from a routine baseline survey could be coupled with other readily available data from national control authorities in order to enable a better insight over Campylobacter contamination status in broiler slaughterhouses. Findings from this work call for subsequent in-depth investigations on technical and hygiene management factors that could impact Campylobacter contamination across broiler slaughterhouses.     

Survival of Escherichia coli O157:H7 and non-pathogenic E. coli on irradiated and non-irradiated beef surfaces

This study examined changes in numbers of pathogenic (PEC) and non-pathogenic (NPEC) Escherichia coli during storage at 10 °C on the surfaces of irradiated (IR) and non-irradiated (NIR) meat pieces excised from the neck, brisket and rump of beef carcasses and in Brain Heart Infusion Broth (BHI) and Maximum Recovery Diluent (MRD). On irradiated meat pieces, there were significant differences between mean PEC and NPEC counts at all sites. Differences in counts were also observed between IR and NIR surfaces and among the three meat sites for both E. coli types. These differences occurred only on IR samples, suggesting that the irradiation associated reductions in normal beef surface flora influenced survival of both E. coli types. PEC and NPEC counts increased during storage in BHI, but only NPEC counts increased in MRD. The results of this study highlight the impact of meat surface type and the presence/absence of the normal beef carcass surface flora on E. coli survival and/or growth during meat storage. Such previously unreported effects, and their precise mechanisms, have direct implications in the development and application of accurate models for the prediction of the safety and shelf life of stored meat.     

Survival of Pseudomonas fluorescens on beef carcass surfaces in a commercial abattoir

The influence of a commercial chilling process (18 h at 10 °C followed by up to 78 h at 2 °C) on Pseudomonas fluorescens inoculated on beef carcass surfaces at four sites, neck (NE), outside round (OR), brisket (BR) and foreshank/brisket (FB) before chilling (“hot inoculated”) or after chilling for 24 h (“cold inoculated”) was investigated. Pseudomonas counts increased significantly at all sites on “hot inoculated” carcasses during storage, but on “cold inoculated” carcasses, counts declined or remained unchanged. On hot and cold inoculated carcasses, differences in Pseudomonas growth or survival were demonstrated between sites. No clear relationships were observed between Pseudomonas growth or survival and chiller relative humidity (RH) or surface water activity (a_w) at the different sites. These results were unexpected, and are discussed in relation to environmental factors that affect the growth/survival of P. fluorescens on carcass surfaces during chilling i.e. temperature, RH, and the relationship of these parameters to surface water activity (a_w).     

The influence of electron beam irradiation of antimicrobial-coated LDPE/polyamide films on antimicrobial activity and film properties

We evaluated the effects of ionizing radiation (1-3 kGy) and incorporation of antimicrobials on the functional properties of low-density polyethylene (LDPE)/polyamide films. We established the antimicrobial effectiveness of several coatings of FDA-approved antimicrobial compounds including sorbic acid, carvacrol, trans-cinnamaldehyde, thymol and rosemary oleoresin using selected food pathogen surrogates. The antimicrobial coatings were applied to one side of the LDPE films and dried. Films were irradiated using a 10 MeV linear electron beam accelerator at room temperature. All films showed inhibition zones in an agar diffusion test against Listeria innocua ATCC 33090 and Escherichia coli ATCC 884. In the liquid culture test, the antimicrobials significantly (p?0.05) reduced the specific growth rate of L. innocua by 3.8-8.5%, and decreased final cell concentration of both strains by 5.7-14.6% and 7.2-16.8%, respectively. All active compounds retained the antimicrobial activity when exposed to 1-3 kGy. Neither the presence of active compound nor dose affected the film's tensile strength and toughness. Additionally, films became more ductile and had improved moisture barrier functionality. Film's oxygen permeability was not affected by either treatment. Results are an initial step toward the development of self-sterile active packaging materials for use in combination with irradiation treatment of foods.     

Effect of γ-irradiation on granule structure and physicochemical properties of starch extracted from two types of potatoes grown in Jammu & Kashmir,India

In this study red and white potato starches were treated with γ-irradiation of 0, 5, 10 and 20 kGy. Physicochemical, pasting and morphological properties of the irradiated starches were investigated. Apparent amylose content, pH, moisture, swelling power and syneresis decreased; whereas carboxyl content, water absorption capacity and solubility increased with increasing irradiation dose. Pasting properties also decreased significantly (p ≤ 0.05) upon increasing the irradiation dose. Observation under scanning electron microscope (SEM) showed surface cracking of the starch granules by γ-irradiation which increased with increase in irradiation dose. X-ray diffraction pattern remained the same upon irradiation but a decrease in relative crystallinity was observed with increasing irradiation dose.     

A comparative study on the effectiveness of chlorine dioxide gas, ozone gas and e-beam irradiation treatments for inactivation of pathogens inoculated onto tomato, cantaloupe and lettuce seeds

The increase in reported food-borne outbreaks linked with consumption of raw fruits and vegetables has motivated new research focusing on prevention of pre-harvest produce contamination. This study evaluates and compares the effectiveness of three non-thermal technologies, chlorine dioxide gas, ozone gas and e-beam irradiation, for inactivation of Salmonella enterica and Escherichia coli O157:H7 on pre-inoculated tomato, lettuce and cantaloupe seeds, and also their corresponding effect on seeds germination percentage after treatments. Samples were treated with 10 mg/l ClO₂ gas for 3 min at 75% relative humidity, with 4.3 mg/l ozone gas for 5 min and with a dose of 7 kGy electron beam for 1 min. Initial load of pathogenic bacteria on seeds was ~ 6 log CFU/g. Results demonstrate that all treatments significantly reduce the initial load of pathogenic bacteria on seeds (p < 0.05). In particular, after ozone gas treatments 4 log CFU/g reduction was always observed, despite the seeds and/or microorganisms treated. ClO₂ and e-beam treatments were noticeably more effective against Salmonella on contaminated tomato seeds, where 5.3 and 4.4 log CFU/g reduction were respectively observed. Germination percentage was not affected, except for cantaloupe seeds, where the ratio was significantly lowered after ClO₂ treatments. Overall, the results obtained show the great applicability of these non-thermal inactivation techniques to control and reduce pathogenic bacteria contamination of seeds.     

Prevalence of and risk factors for Campylobacter spp. contamination of broiler chicken carcasses at the slaughterhouse

A study was conducted in 2008 to estimate the prevalence and identify the risk factors for Campylobacter spp. contamination of broiler carcasses during the slaughtering process. A pool of 10 caeca and one carcass were collected from 425 batches of broiler chickens slaughtered in 58 French slaughterhouses over a 12-month period. Potential risk factors were identified according to the Campylobacter contamination status of carcasses and processing variables identified from questionnaires. The statistical analysis took into account confounding factors that have already been associated with the presence of Campylobacter on carcasses such as the slaughter age of the chicken or seasonal variations. Campylobacter spp. were isolated from 77.2% of caeca (95% CI 73.2 to 81.2) and from 87.5% of carcasses (95% CI 84.4 to 90.7). A multiple logistic regression showed 4 parameters as significant risk factors (p < 0.05) for contamination: (I) batches were not the first to be slaughtered in the logistic schedule (OR = 3.5), (II) temperature in the evisceration room was higher than 15 °C (OR = 3.1), (III) dirty marks on carcasses after evisceration were visible (OR = 2.6) and (IV) previous thinning of the flocks, from which slaughtered batches came, had occurred at the farm (OR = 3.3). This last result highlighted the need for sanitary precautions to be taken when catching birds for transport. At the slaughterhouse, evisceration seemed to be the operation contributing most to the spread of contamination. Effective risk management solutions could include the systematic external rinsing of carcasses after evisceration and the implementation of slaughtering schedules according to the Campylobacter contamination status of flocks.