The shelf-life of a product is the period of time during which the food retains its qualitative characteristics. Bacteria associated with meat spoilage produce unattractive odours and flavours, discolouration, gas and slime. There are several neglected alterations that deserve more attention from food business operators and competent authorities. Ropy slime is a typical alteration of the surface of vacuum and modified atmosphere packed cooked meat products, that causes major economic losses due to the increasingly sophisticated consumer requirements. This is a review article that aims at raising awareness of an old problem of new concern, in the light of new advances and trends for understanding the aetiology of the phenomenon, the origins of contamination and the prevention measures.

Possible contamination by Staphylococcus aureus of the production environment and of the meat of a canned meat production factory was analysed. A total of 108 samples were taken from nine critical control points, 13 of them were positive for S. aureus. None of the isolates produced enterotoxins. To determine how much time can elapse between can seaming and sterilisation in the autoclave without any risk of enterotoxin production by S. aureus, the growth and enterotoxin production of three enterotoxin A producing strains of S. aureus (one ATCC strain and two field strains) in canned meat before sterilisation was investigated at three different temperatures (37, 20 and 10 °C). Two types of meat were used, one with and one without sodium nitrite. In the canned products, the spiked bacteria spread throughout the meat and reached high levels. Enterotoxin production was shown to start 10 hours after incubation at 37 °C and after 48 h after incubation at 20 °C; the production of enterotoxin was always detected in the transition between the exponential and the stationary growth phase. At 10 °C, the enterotoxin was never detected. The statistical analysis of the data showed that the difference between the two different types of meat was not statistically significant (p value > 0.05). Since it is well known that following heat treatment, staphylococcal enterotoxins, although still active (in in vivo assays), can be undetectable (loss of serological recognition) depending on the food matrix and pH, it is quite difficult to foresee the impact of heat treatment on enterotoxin activity. Therefore, although the bacteria are eliminated, the toxins may remain and cause food poisoning. The significance of the results of this study towards implementing good manufacturing practices and hazard analysis critical control points in a canned meat factory are discussed with reference to the management of pre-retorting steps after seaming.

The term ‘packaging’ refers to the technological intervention aimed at the protection of food from a variety of factors, which provokes the product detriment. Packaging is considered as one of the most interesting technological aspects and a constantly evolving issue in food production. This paper aims at the evaluation of the properties of packaging currently used in the meat industry and analyses the advantages, the disadvantages and the microbiota involved. Packaging is a coordinated system, which prepares the products for transportation, distribution, storage, marketing and consumption. Even if several packaging alternatives are proposed, the common purpose is to guarantee high standards, yet maintaining the required characteristics as long as possible. Meat is a dynamic system with a limited shelf-life and the nutritional and sensory properties may change during storage due to microbial activity and physical or chemical changes. Microbial spoilage, for instance, determines an impact in meat, producing unattractive odours, flavours, discolouration, gas and slime.

The transfer of antibiotic resistance <em>via</em> the food chain is a global concern. Nevertheless, more attention is required to non-pathogenic strains, such as spoilage bacteria, which could transmit genes to pathogens. Although Lactic Acid Bacteria are microorganisms generally recognized as safe, <em>Leuconostoc mesenteroides</em> may reach and maintain high concentration levels on the surface of cooked products and ready-to-eat products throughout the entire shelf life. It is therefore important to consider the possibility for this species to carry antibiotic- resistance genes. The present research deals with the antibiotic susceptibility profile of strains of <em>L. mesenteroides</em>, isolated from vacuum packaged cooked meat products. In this study, the antimicrobial susceptibility of <em>L.mesenteroides</em>, previously isolated from cooked ham, was investigated through disk diffusion assay according to CLSI standards. Isolated strains from ready-to-eat food show high levels of resistance to ampicillin and methicillin and, according to a settled panel of 21 antibiotics, the antibiotic resistance was demonstrated for the 50% of the tested molecules.