The research approach is to survey current commercial practice and then to select representative commercial sites to sample for pathogens present in the waste.
<p><strong>Objective 1 </strong><br>
A literature search, based on a combination of traditional and electronic information retrieval systems, will be carried out to ensure that the project is founded on the most up-to-date information. A network of world wide contacts with research groups working on abattoir waste topics will also be established.
<p><strong>Objective 2 </strong><br>
Using the DFAS and School of Veterinary Science database of abattoirs, a representative selection of up to 30 plants will be surveyed for the different types of waste spread on land, the quantities stored, the times and conditions of storage, the timings, quantities and methods of application and the types of land on which it is applied. Those chosen will include both large and small plants and red meat and poultry processing units. The survey will be carried out by personal visit, inspection and interview.
<p><strong>Objective 3 </strong><br>
Methods for isolation/enumeration of the microbial pathogens will be developed in collaboration with the Centre for Applied Microbiology & Research (CAMR), while those for the protozoan parasites will be developed in collaboration with Thames Water (Reading). The methods selected will be validated using various types of abattoir wastes artificially inoculated with a range of levels of pathogens.
A survey of the pathogens in commercially produced abattoir waste will be carried out by selecting abattoirs disposing of different types of waste (identified in Objective 2), collecting a representative number of samples and examining them for the presence of foodborne pathogens. The sampling plan will include four seasons and various geographical locations. An initial working plan for the survey is based on our preliminary discussions with the industry, which have identified seven types of abattoir waste spread on agricultural land. The wastes presently spread on land, broken down by species are:
<p><strong>Cattle:</strong> lairage waste, rumen contents<br>
<strong>Sheep:</strong> lairage waste, rumen contents<br>
<strong>Pigs:</strong> stomach contents, gut contents, blood<br>
<p>However, it should be kept in mind that<br>
a) the types of wastes that are eventually targeted by the survey, <br>
b) the types of pathogens targeted within each type of waste, <br>
c) the number of abattoirs included in this survey and d) the number of samples for each type of waste, will only be chosen after completion of Objectives 1 & 2.
<p>The above also applies to poultry abattoir wastes, although there are reasons to believe that at present poultry wastes are generally rendered and are not spread onto land.
Abattoir wastes permitted to be spread on land fall into several categories: gut contents, blood, lairage waste and liquid from washing processes.
<p>The initial levels of pathogens in some of these wastes are likely to be high and may present a hazard to human health.
<p>Before disposal, wastes are stored for a variable period of time, under varying conditions. It is unclear whether this leads to increase or decrease in the number of pathogens and therefore under what circumstances storage may increase or decrease the potential hazard. Storage and different storage conditions may affect different pathogens in different ways.
<p>The proposed research will therefore examine the prevalence of the major foodborne pathogens in abattoir waste destined for disposal on agricultural land. This will allow the formulation of policies on control of waste disposal based on a clear view of the risks from the prevalence of specific pathogens.
The final report, "<a href="http://www.foodbase.org.uk/results.php?f_report_id=183" target="_new">The Levels of Pathogens in Abattoir Wastes</a>" is available at Foodbase, an open access repository of the <acronym title="Food Standards Agency">FSA</acronym>.
<p>Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food Standards Agency Research webpage</a>.