WP2: Food safety conventional production


Work package number 2    Start date or starting event: Month 3
Work package title conventional production
Participant short name




To evaluate and model how defined food safety and quality parameters change in food model systems:

(1) when different ingredients are combined in raw and heat treated RTE and convenience products,

(2) during their distribution and

(3) storage, up to the consumption by the consumers including the vulnerable ones.

The data collected will be used to define performance objectives (POs) and process criteria (PCs) for ingredients and production processes with the aim support the achievement of FSOs and microbial criteria currently established in the EU-legislation for RTE.  



T. 2.1 Review of knowledge that is relevant for development of guidelines to the industry and as input for the development of the IT tool.

T.2.2 Investigation of quality and safety changes during mixing of conventional ingredients and preparation of RTE and minimally processed model products.

T.2.3 Investigation of quality and safety changes in RTE products during production, transport and storage  

Sub-task 2.3.1 Influence of supply chain variables

Sub-task 2.3.2 Influence of in-house processing procedures

Sub-task 2.3.3 Effect of distribution chain variables. 

T.2.4 Investigation of pathogenicity changes of target pathogens in RTE products in relation to different production technologies.

T.2.5 Explore possible performance objectives and process criteria for production of mixed ready-to-eat and convenience products to ensure quality and safety of the final products.


D.2.1. Report on relevant safety and quality changes associated with mixing of ingredients during preparation of RTE products

D.2.2. Report on relevant processing, distribution and storage factors affecting safety and quality of RTE D.2.3.Report on processing steps able to affect the pathogenicity of Salmonella enterica and Listeria monocytogenes strains contaminating RTE products.

D.2.4. Report on suggested POs and PCs for categorised RTE products.

D.2.5. Guidelines to the industry based on essential data for risk assessment and decision support of RTE and convenient products. 

Results so far

The results collected so far in WP2 in different kinds of salads (pasta salads, rice salads, spelt salads, potato salads) and ready to heat (RTH) meal products (meatball dinner, fish soup, chicken stew, paella)  show that:

Bacillus cereus and Listeria monocytogenes can occasionally contaminate the investigated RTE products but at very low concentrations (<100 CFU/g).

- Fresh vegetables represent the main vectors of pathogens.

- Maintaining the modified atmosphere is one of the main control measures especially against spore forming bacteria.

- Salads hardly support growth of Listeria and Staphylococci, and the growth of Listeria is even less at abuse temperature than at 4°C depending on the recipes.

- Presence of meat in salads can enhanced the survival and the growth of artificially inoculated pathogenic bacteria in salads even at low pH.

- The product pH can play a significant role in determining the potential growth/survival of the pathogenic bacteria.

- Low pH seems to support the lactic acid population during the product shelf life, at both refrigeration and abuse temperatures.

- There is a substantial intra-batch and inter-batch variability in total number of aerobic mesophilic count, lactic acid bacteria and in sensory qualities of convenience ready to heat (RTH) meal products.

- RTH products support the growth of L. monocytogenes.

- Heating a convenience ready to heat meal products in a microwave oven, following recommended heating instructions, is not always effective in eliminating L. monocytogenes, if present in the food products.

The products we are currently working with are different pasta salads, with or without fresh vegetables and meat, in which we model growth dynamics of L. monocytogenes at different temperatures using primary (i.e., Baranyi model with and without lag, logistic curve and the Rosso model) and secondary models (i.e., square root model of Ratkowsky and the gamma model).

PastaW2.png  Pasta2W2.png


Poster - De Cesare A., Trevisani M., Mancusi R., Costanza C., Bovo F., Manfreda G. Preliminary assessment of the key variables impacting survival and growth of Listeria monocytogenes and Listeria spp in RTE products during storage.

Poster - Tessema G.T., Fagereng T.M., Elin R., and Skjerdal T. Microbiological challenge study: factors affecting target pathogen recovery from food.

Oral presentation - Transcriptome of Listeria monocytogenes adapted to sub-lethal concentrations of lactic acid, acetic acid and hydrochloric acid.

Publication - Microarray-based transcriptome of Listeria monocytogenes adapted to sublethal concentrations of acetic acid, lactic acid, and hydrochloric acid.