Obiettivo
1. To determine the effect of MAP/VP on the selection of a spoilage association from the initial microflora. As the spoilage flora develops, changes in the physicochemical attributes of beef, pork, lamb and meat products will be quantified;
2. To develop rapid microbial identification methods, to enable dynamic analysis of changes in developing microflora;
3. To determine the influence of MAP/VP and the members of the spoilage association, particularly lactic acid bacteria, on the growth of the following food poisoning organisms; Listeria monocytogenes, Verotoxigenic E. coli, Staphylococcus aureus, Salmonella spp., Yersinia enterocolitica;
4. To analyze the physicochemical characteristics of MAP/VP meats during storage to identify changes that could be used to monitor safety and freshness. The physicochemical characteristics will include volatile compounds such as sulphur compounds, acetoin, diacetyl etc., and changes in protein patterns as shown by electrophoresis. Changes in these components will be correlated with the microbial ecology. Moreover, suitable sensing or detection systems for changes will be studied (hydrogen sensors for hydrogen and volatiles such as organic sulphur compounds);
5. To examine changes in the organoleptic properties of the products. Organoleptic acceptability of meat and meat products will be correlated with the microbial ecology and with physicochemical changes;
6. To correlate time-temperature integrals assessed by various electronic, enzymatic or chemical devices, with changes in organoleptic properties and organoleptic acceptability.
An investigation into the potential indicators for spoilage in pork and poulty products packed under vacuum pack 100% carbon dioxide, 100% nitrogen, 20% carbon dioxide and 80% oxygen (VP/MAP) showed that the decrease of 1-lactate and the increase of acetate during the storage could be used as potential indicators.
The effect of VP/MAP meat samples inoculated with Staphylococcus, Salmonella enteriditis and pseudomonads was also investigated.
A selective medium suitable for distinguishing between species of meat pseudomonads has been developed and a rapid characterization has been developed, tested and used to analyze the proportions of Pseudomonas species present in beef steaks. The 3 meat Pseudomonas species, fragi, fluorescens and lundensis can now be distinguished using the rapid methods.
Work on the survival of Yersinia enterocolitica in the same atmospheres revealed that growth of this pathogen, on lamb pieces stored at 0 C, was unusual, inhibited in atmosphere containing 80% oxygen/20% carbon dioxide but not in 50% carbon dioxide/50% nitrogen.
The effects of gas composition, temperature and packaging systems on the growth and survival of Salmonella typhimurium on both beef and cured meat products were examined. Many of the selective diagnostic media that exist for salmonellae are not sufficiently selective when looking for low numbers of salmonellae. The presence of selective agents in these media can also reduce the recovery of any sublethally damaged cells that may be present. The use of antibiotic resistant (marked) strains allows the selective isolation of the 'marked' strains byincorporation of the appropriate antibiotics in the recovery medium, thus eliminating the 'background' from other bacteria. 4 antibiotic resistant ('marked') strains of S. typhimurium were produced and validated for use in the inoculation experiments. Physicochemical studies concentrated on the appearance of D-lactic acid in beef and on the identification of headspace vola tiles within packs and a method for detecting leaking packs is being investigated.
Campo scientifico
- natural scienceschemical sciencesorganic chemistryorganic acids
- natural sciencesbiological sciencesmicrobiologybacteriology
- medical and health sciencesbasic medicinepharmacology and pharmacypharmaceutical drugsantibiotics
- engineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringsensors
- medical and health sciencesbasic medicinepharmacology and pharmacydrug resistanceantibiotic resistance
Programma(i)
Argomento(i)
Data not availableInvito a presentare proposte
Data not availableMeccanismo di finanziamento
CSC - Cost-sharing contractsCoordinatore
14123 Athens
Grecia