ASSESSMENT OF THE HYGIENIC CHARACTERISTICS OF A PROCESS FOR THE DISTRIBUTION OF PROCESSED MEATS, AND OF STORAGE-CONDITIONS AT RETAIL OUTLETS

The temperature histories of boxes of fresh sausages and wiener sausages were collected from three consignments in each of nine loads carried in each of two refrigerated trucks that distributed the products to retail outlets. Each temperature history was integrated with respect to models describing the dependencies on temperature of the growths of Escherichia coli, Listeria monocytogenes and leuconostocs. A storage efficiency factor was calculated for each history from the calculated proliferation of leuconostocs. Both types of product in truck A cooled towards the truck air temperature of -3.5 degrees C during transportation periods of up to about 36 h. Temperatures of all product remained too low for the growth of E. coli. All growth of L. monocytogenes was calculated to be <1 generation, except when transportation was preceded by assembly of a consignment on the day before dispatch. Most storage efficiency values for fresh sausages and wiener sausages were >40% and 13%, respectively, with the highest values being obtained for the longest histories. The temperatures of fresh sausages in truck B generally rose towards the truck air temperature of 2 degrees C. The temperatures of wiener sausages generally fell or remained unaltered. However, control over product temperatures was lost with three consignments in which temperatures rose to >7 degrees C. Proliferations of E. coli <1 generation, and of L. monocytogenes >1 generation were calculated for some temperature histories. Most storage efficiency values for fresh and wiener sausages were <40% and <13%, respectively. The process of transportation in truck B would be hygienically inadequate if transit times were extended beyond one working day. Thirty-seven of the temperature records included post-delivery periods that were of sufficient duration for the conditions experienced by products at 25 retail outlets to be identified. The temperature histories from five outlets were characterized by average temperatures >4 degrees C, storage efficiencies <16%, E. coli proliferations >1 generation and/or L. monocytogenes proliferations averaging >1 generation/day. Poor control of product temperatures at those outlets was variously due to mismanagement of loading product from transport to storage, high temperatures of delivered product, or high operating temperatures of storage chillers. The temperature histories from 18 outlets were characterized by average temperatures between 1.3 and 3.5 degrees C, storage efficiencies between 19 and 35%, little (less than or equal to 0.2 generation) or no E. coli proliferation and proliferation of L. monocytogenes averaging <1 generation/day. Superior control over product temperatures occurred at only two outlets, where average temperatures were about 0 degrees C, storage efficiencies about 50% and proliferation of L. monocytogenes averaged <0.1 generation/day.