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.

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.

Several widespread occurrences of anomalous blue coloration of Mozzarella cheese have been recorded in the United States and some European countries. Official laboratory analysis and health authorities have linked the occurrences to contamination of the processing water with strains of Pseudomonas fluorescens, although several experts questioned how to unequivocally link the blue color to the presence of the microorganism. To establish a method to determine whether a given Pseudomonas spp. strain is responsible for the defect and study the evolution of the coloration under different storage conditions, we developed an in vitro system for the evaluation of blue coloration of Mozzarella cheese intentionally contaminated with strains of P. fluorescens. The purpose of the system was to determine whether P.fluorescens strains, isolated from Mozzarella cheese with anomalous blue coloration, were able to reproduce the blue coloration under controlled experimental conditions. Thirty-six trials of experimental inoculation of Mozzarella cheese in different preservation liquids were conducted using various suspensions of P.fluorescens (P. fluorescens ATCC 13525, P.fluorescens CFBP 3150, and P. fluorescens 349 field strain isolated from blue-colored Mozzarella cheese) at different concentrations and incubated at different temperatures. Growth curves of all tested P.fluorescens strains demonstrated that after 3 d of incubation the concentration was generally >10(6) cfu/g of Mozzarella cheese incubated in either tryptic soy broth (control) or conditioning brine. Prolonged incubation for 5 d at either 20 °C or 8 °C led to concentrations up to 10(9) cfu/g of Mozzarella cheese incubated in tryptic soy broth and up to 10(8) cfu/g of Mozzarella cheese incubated in preservation liquid. All Mozzarella cheeses inoculated with the field strain of P. fluorescens, except those opened 1h after packaging and stored at 8 °C, showed the characteristic anomalous blue coloration, which appeared from 1 to 72 h after opening the packaging, and was proportional to colony count, duration of storage, and storage temperature. With the proposed system, which enabled a larger number of samples to be analyzed under controlled experimental conditions and a large amount of data to be generated in a short time, we described precisely how and under which conditions the presence of P. fluorescens in Mozzarella cheese is responsible for the anomalous blue coloration. The system will help producers intercept contaminated batches and help consumers avoid the conditions under which the defect can appear.

A quantitative microbiological risk assessment model for the cross‐contamination transmission route in the kitchen (KCC) is presented. Bacteria are transmitted from contaminated (chicken) meat to hands, kitchen utensils, and other surfaces, subsequently contaminating a salad. The model aims to estimate the fraction of bacteria on the meat that is ingested due to cross‐contamination, determine the importance of the different transmission routes, and assess the effect of scenarios (interventions) on the fraction ingested. The cross‐contamination routes defined, bacterial source‐to‐recipient transfer fractions as available and derived from literature, and important characteristics (e.g., washing in cold water vs. hot water with soap) shaped the KCC model. With this model, 32 scenarios of an eight‐step preparation of a “meat and salad” meal in a domestic kitchen were stochastically simulated. The “cutting board‐salad” route proved dominant and the salad plays a major role in the final exposure. A realistic scenario (washing hands, cutting board, and knife with cold water after cutting the meat) estimates that a mean fraction of 3.2E − 3 of the bacteria on the meat is ingested. In the case of “hand washing with hot water and soap” and “cutting board and knife replacement,” the mean fraction ingested is 3.6E − 6. For a subsequent meal, where the contaminated sources were kitchen fomites, the estimated mean fraction is 4.3E − 4. In case of hamburger, part of the bacteria is unavailable for cross‐contamination, resulting in a mean fraction ingested of about 5.4E − 5. The role of the dishcloth in cross‐contamination transmission proved to be minor.

Regulation (EC) No. 1099/2009 on the protection of animals at the time of killing establishes an obligation to spare animals any avoidable suffering or stress prior to their slaughter. Although it has been pointed out that stressors also include noise, which can cause suffering and affect the quality of the meat, current legislation does not set a limit for environmental noise in slaughterhouses. This study was conducted in three slaughterhouses in central Italy to assess the environmental acoustic level using a smartphone app. The selected, medium-sized slaughterhouses for pigs and cattle were subjected to measurements using a sound-level meter (Noise Meter for iOS) during working hours at the unloading area and lairage, along the chute to the restraining pen, at the time of stunning and at the slaughter hall. For the bovine lines the average values expressed in dB ranged from 76.33 (SD 2.08) to 93.00 (SD 2.14) for abattoir 1, from 75.00 (SD 1.87) to 92.33 (SD 4.89) for abattoir 2 and from 75.67 (SD 7.09) to 88.83 (SD 4.79) for abattoir 3. For the pig lines the average values expressed in dB ranged from 77.50 (SD 3.11) to 100.33 (SD 1.53) for abattoir 1, from 83.00 (SD 2.00) to 99.75 (SD 2.63) for abattoir 2 and from 71.20 (SD 6.49) to 99.50 (SD 1.31) for abattoir 3. Data show that the pig slaughter line was always noisier than the cattle line and the slaughter hall always showed the highest values (i.e. 100 dB), when compared to the unloading area (i.e. 79 dB).

Several growth curves for selected pathogens and hygiene indicators alone and vs selected dairy starter cultures (LAB) and commercial probiotics have been performed. All strains for LAB and commercial probiotics were inoculated as pure cultures into skim milk to get an initial cocci:bacilli:enterocci ratio of 2:1:1 and a concentration of approximately 10⁷ cfu mL^–1 until challenge vs selected pathogens and hygiene indicators. Selected pathogens came from the collection of the Laboratorio di Ispezione degli Alimenti di O.A. or were reference strains (Escherichia coli, CSH26 K12, Staphylococcus aureus 27R, Salmonella Derby 27, Pseudomonas fluorescens ATCC 13525, Listeria innocua ATCC 33090). Each strain was inoculated into skim milk to get an initial concentration of approximately 10⁶ cfu mL^–1. Growth curves in skim milk for the following challenges were studied: i) sterility control; ii) association LAB; iii) association of LAB vs each selected pathogen or hygiene indicator; iv) selected pathogen or hygiene indicator alone. The challenges were carried out in BHI broth and in skim milk at 37°C. The highest reduction was observed in milk but in general the association of LAB and the probiotic was able to limit the growth of pathogens and hygiene indicators.