Exposure to inhalable dust of workers shackling birds frequently exceeds occupational exposure level in abattoirs in Western France.

1. The objectives of this study were to measure the exposure of workers to dust when shackling poultry in abattoirs, and to identify the most effective measures to prevent human exposure to dust. The relationship between respiratory health of workers and their occupational exposure to dust was assessed. 2. Exposure to dust (aerial particles inhaled through the nose and mouth) exceeded the occupational exposure limit (maximum 10 mg/m3 over 8 h) in 65 out of 109 workers from 27 abattoirs, in the context of high levels of ambient aerial dust in small, closed shackling cubicles. Ceiling air ducts for supply of air reduced worker exposure to dust in these buildings. 3. Two-thirds of the 86 workers interviewed reported work-related respiratory symptoms. The self-reported risk of suffering from coughing tended to be associated with the highest exposure to inhalable dust and respiratory dust (aerial particles penetrating up to alveoli) observed in the study. 4. The present study demonstrates that workers may be exposed to considerable amounts of dust when shackling birds before stunning.

A multi-pronged approach to the search for an alternative to formaldehyde as an egg disinfectant without affecting worker health, hatching, or broiler production parameters.

Research was carried out to determine the effectiveness of 4 hatching eggs disinfection processes (i.e., disinfecting products and administration method) using a multi-pronged approach assessing the reduction of microbial eggshell contamination, the effects on worker exposure, hatching results and broiler performance, and, finally, suitability for use in commercial hatcheries. The 4 disinfection processes were: sodium dichlorocyanurate (DC) by thermonebulization, hydrogen peroxide 6% by nebulization (HP6), electrolyzed oxidizing water (EOW) by fogging, and hydrogen peroxide 30% vapor (HP30). In order to meet commercial hatchery conditions, the tested products were applied in an experimental hatchery by aerial disinfection in a dedicated room, not sprayed directly onto the eggs. Compared to the untreated control group, eggshell microbial load was significantly decreased by over 1 log10 cfu per egg in groups DC and HP30. These results were confirmed during a second experiment. In addition, these 2 products comply with legal requirements on worker exposure. Fertility and hatching results were significantly higher in group HP30 than in group DC, with no impact on chick quality and subsequent broiler performance. Under these study conditions, the disinfection process (i.e., administration of the product, contact with the eggs and aeration) lasted 65 min in group DC vs. 135 min in group HP30. When considering commercial hatchery conditions, this difference in application time confers a clear advantage on the DC process. Moreover, the investment required for HP30 is much higher than for DC. Overall, HP30 presented a clear advantage for hatching results whereas DC is a relatively more practical and less expensive disinfection process. To our knowledge, this is the first report on the use of hydrogen peroxide vapor as an egg disinfection process. Further research is needed to confirm the results of this study under commercial hatchery conditions.

Identifying risk factors for eggshell contamination by Bacillus cereus group bacteria in French laying farms.

1. The growth of Bacillus cereus group bacteria often limits the shelf-life of pasteurised liquid egg products and is also a putative toxin producer. This study was performed to better understand the route of contamination by B. cereus in egg products by studying the factors affecting eggshell contamination on-farm. 2. Eggs were collected in warm and cold seasons in 50 conventional laying farms in Western France. Egg surfaces were analysed for the presence of B. cereus group bacteria, environmental measurements were recorded and production practices were identified through a questionnaire filled out by the farmers. 3. A total of 44% of the farms were contaminated by mesophilic and 10% by psychrotrophic B. cereus group bacteria. No significant effect of the season was observed, whatever the thermal type. Several procedures were associated with reduced eggshell contamination by mesophilic bacteria, including the limitation of dust formation from manure and feeding and efficient disinfection of the silo, houses and the sanitary wall between houses. 4. The research highlights the need to promote prevention strategies, from farm to fork, for the control of eggshell and putative subsequent egg product contamination by B. cereus group bacteria.

Biodiversity of psychrotrophic bacteria of the Bacillus cereus group collected on farm and in egg product industry.

The aim of the present study was (i) to type, by genotypic and phenotypic methods, a collection of psychrotrophic bacteria belonging to the Bacillus cereus group collected in a farm and in 6 egg breaking industries during a period covering a warm and a cold season, and (ii) to characterize the egg product spoilage (growth in liquid whole egg) and the sanitary risk potential (cytotoxic activity on Caco-2 cells and adhesion on stainless steel) of each isolate of the collection. The investigation of specific psychrotrophic and mesophilic signatures together with the study of ability to grow at 6 °C and/or at 43 °C on optimal agar medium allowed highlighting twelve profiles, the major one corresponding to the species Bacillus weihenstephanensis (46.2% of the collection). The diversity of the profiles depended on the season and on the origin of the isolates. In terms of food spoilage, all the isolates were able to grow at the same level in liquid whole egg and in optimal medium, even at low temperature. Under the same conditions, the cytotoxic activity depended on the isolate, the medium and the temperature. At 10 °C, no isolate was cytotoxic at 10 °C in liquid whole egg and only one, belonging to the Bacillus weihenstephansensis species, in the optimal medium. All the isolates were able to adhere on stainless steel at various levels, from 2.6±0.2 log cfu/cm(2) to 4.9±0.1 log cfu/cm(2). A large majority (80.8%) was strongly adhering and could lead to the formation of biofilms in industrial equipments.

Expression and functional implications of troponin T isoforms in soleus muscle fibers of rat after unloading.

The expression pattern of troponin T (TnT) isoforms was studied in rat soleus muscle fibers in control and after hindlimb unloading (HU) conditions. To determine the functional consequence of TnT expression, the fibers were also examined for their calcium activation characteristics. With regard to TnT expression, four populations of fibers were distinguished in control muscle. Slow fibers expressing only slow isoforms of TnT (TnT1s, 2s, 3s ) were predominant (54%). Hybrid slow fibers (16%) differed from slow fibers by the additional expression of two TnTf isoforms. Hybrid fast fibers (22%) expressed slow and fast isoforms of TnT while fast fibers (8%) expressed only fast TnT isoforms. The expression of the other regulatory protein isoforms was checked for each population. The contractile experiments revealed steeper slopes of the tension/pCa relationship from hybrid slow fibers expressing fast TnT in a completely slow molecular environment. The expression of TnTs in hybrid fast fibers did not modulate the intrinsic co-operativity. After HU, the fast population was increased and reached 55%. The slow population decreased to 41% and a very small amount of hybrid slow fibers remained (4%). These data demonstrated the implication of TnT isoforms in the calcium activation properties and, more particularly, in the modulation of co-operativity within the myofibrillar lattice. Regulation of TnT expression appeared as a very fast and complete process compared to moderate changes of TnC and TnI.