Antoine Collignan

Osmotic treatment of fish and meat products

In the review, the mass fluxes occurring during the operation are identified and the potential of osmotic treatment (OT) as an alternative to conventional processes is evaluated. Product quality development during processing and storage is assessed. Pilot and industrial applications are investigated. In terms of prospects, some future research areas that have not yet been investigated are presented.

Soaking process in ternary liquids : Experimental study of mass transport under natural and forced convection

Abstract Cross mass transport during the soaking process of model food gel (gelatin, carraghenan) in concentrated solutions (salt-sucrose-water) at 10 °C was investigated using a rotating gel disc device. The concentration profiles in gel were analyzed. The experimental results confirmed the theory that component concentrations are not functions of the disc radius. Two sets of experiments were carried out to study the influence of the main process variables (solute concentration, processing time) on mass transport under forced and natural convection. The results showed that the presence of sucrose enhanced water loss and hindered salt penetration whatever the hydrodynamic conditions. Rotation speed increased water loss as solute concentration increased but had no effect on salt gain, while it hindered sucrose gain. Photographs also showed the presence of very strong natural convection phenomena.

Pulsed vacuum brining of poultry meat: interpretation of mass transfer mechanisms

Abstract Pulsed vacuum brining (PVB) of meat products in salt-concentrated solutions gives rise to hydrodynamic mechanisms that facilitate solution infiltration into the meat structure. Previous studies have shown that these mechanisms can only function with porous structures. The estimated apparent porosity of meat is 1.69% (v/v). The difference in total pressure is the key to efficient infiltration––it forces occluded and/or dissolved gases from the meat during vacuum processing and then, upon the return to atmospheric pressure, solution infiltrates the pores from which the gases were expelled. Transfers between the occluded solution and the inner surfaces of the meat pores then occur within the product throughout brining under atmospheric pressure conditions. The solution is expelled again from the product in the next vacuum cycle. During PVB of poultry meat, solution infiltration and internal transfer account for respectively 9–22% and 7–17% of the salt gain obtained with this process.

The effects of sodium lactate and starter cultures on pH, lactic acid bacteria, Listeria monocytogenes and Salmonella spp. levels in pure chicken dry fermented sausage

Two starter cultures (A and B) and seven sodium lactate concentrations were evaluated for chicken raw dry-fermented sausage processing. Starter culture B contained more lactic acid bacteria and less staphylococci than starter A. Their effects on acidification and inhibition of pathogens (Listeria monocytogenes and Salmonella spp.) were monitored. Starter culture B grew faster and was less inhibited by sodium lactate, thus inducting a faster and more important pH drop into the sausages. With lower pH, sausages processed with B starter were less contaminated by Listeria monocytogenes. The type of starter was found to influence the end-product pH, lactic acid bacteria content and extent of Listeria monocytogenes contamination. A 30-member panel did not note differences between sausages processed with the different starter cultures when lactate was added. Adding sodium lactate to the sausage mix reduced the pH drop in the dry sausage product. This acidification inhibiting effect of sodium lactate was greater for A. Sodium lactate significantly inhibited lactic acid bacteria development but did not reduce Listeria monocytogenes contamination frequency of the batches, unlike in many literature data. Sodium lactate may however control the acidification of the sausage processed with starter B, in order to obtain moderately acidified fermented sausages. A simple kinetic model was applied to our data. The sodium lactate content and especially the type of starter culture often had a significant effect on the four parameters of this empirical model (lag time, acidification time, initial and final pH).

Equipment design for osmotic treatments

Recent osmotic treatment (OT) applications make it necessary to develop specially designed items of equipment, particularly where a high level of dehydration is necessary. This paper defines the functions required by users of osmotic dehydration equipment and presents seventeen principles used to contact foods with a concentrated solution. It then compares the different technical solutions.

Pulsed vacuum brining of poultry meat: experimental study on the impact of vacuum cycles on mass transfer

Abstract Salting of meat products is often accelerated by using a continuous vacuum salting–tumbling process. The pulsed vacuum brining (PVB) process involves plunging a food product into a concentrated salt solution followed by an alternation of cycles under partial vacuum and then atmospheric pressure conditions. The effects of key vacuum cycle variables on mass transport were studied by PVB of turkey meat in different concentrated sodium chloride solutions. PVB led to a product that was more salted and less dehydrated than products brined under atmospheric pressure brining conditions, thus boosting mass yields. Food products obtained by PVB have a more uniform salt and water distribution from the surface to the core. This study demonstrated that the number of vacuum cycles, processing with a long vacuum phase under a low residual pressure and a shorter atmospheric pressure phase enhanced the effects of PVB on mass transfers (increased salt gain, decreased water loss, thus increasing mass yields).

DESCRIPTION AND ANALYSIS OF TIMBER DRYING KINETICS

ABSTRACT In this paper an experimental and semi-analytical technique is described that provides a method of estimating a macroscopic drying kinetics curve and internal moisture content profiles is described. Moisture gradients and the time evolution of these gradients are analysed as a function of the air drying parameters (dry-bulb, wet-bulb temperature and the velocity) and the product parameters (thickness and density). The material used as an illustration is a maritime-pine-wood.

Decontamination of chicken skin surfaces inoculated with Listeria innocua, Salmonella enteritidis and Campylobacter jejuni by contact with a concentrated lactic acid solution

1. The aim was to establish how poultry skin could be efficiently decontaminated without changing its organoleptic properties. 2. Chicken skins were surface inoculated with Listeria innocua and treated with different acid solutions (2 and 10% lactic acid for 1 and 30 min). Surviving bacteria were enumerated immediately after treatment and after 7 d storage at 4°C. 3. Reductions of up to 2.6 log were reached immediately after treatment. The treatment effect persisted for 7 d storage, when the reduction exceeded 4.59 log for the strongest treatment. 4. Residual levels of lactic acid were not significantly higher than in untreated controls, except for the strongest treatment. A tasting panel found no significant difference between controls and samples. 5. After the initial results, an apparently optimal treatment (5% lactic acid for 1 min) was applied on chicken skins’ surface inoculated with a mix of Listeria innocua, Salmonella enteritidis and Campylobacter jejuni. Treatment efficacy was assessed immediately after treatment and after 1, 4 and 7 d storage. 6. This treatment seems to be very promising from a food processing standpoint, being fast and allowing decimal reductions of 2.00 log for Listeria innocua and 2.38 log for Salmonella enteritidis after 7 d storage, neither significantly increasing skin lactic acid nor causing any organoleptic modifications to the product. The effect of the treatment is significant after one day storage for Listeria innocua and after 4 d storage for Salmonella enteritidis.

Effect of steam and lactic acid treatments on the survival of Salmonella Enteritidis and Campylobacter jejuni inoculated on chicken skin

Campylobacteriosis and salmonellosis are the most frequently reported zoonotic infectious diseases. The present work evaluated the effectiveness of steam treatment at 100 °C for 8s, a 5% lactic acid treatment for 1 min and their combination for inactivating Salmonella Enteritidis and Campylobacter jejuni inoculated on chicken skin. The impact of each treatment on the total aerobic mesophilic bacteria and the effect of rinsing after contact with lactic acid were also evaluated. Residual bacteria were counted immediately after treatment or after seven days of storage at 4 °C. Results demonstrated the immediate efficiency of the steam and the combined treatments with reductions of approximately 6 and 5 log cfu/cm2 respectively for S. Enteritidis and C. jejuni. They also showed significant reductions (equal to or >3.2 log cfu/cm2) in the total aerobic mesophilic plate count. Lactic acid had a persistent effect on pathogen growth during storage which was significantly higher when the skin was not rinsed, reaching reductions of 3.8 log cfu/cm2 for both S. Enteritidis and C. jejuni. Only the combined treatments significantly reduced the recovery of the total aerobic mesophilic bacteria during storage. The significant reductions in both pathogens and total aerobic mesophilic bacteria on treated chicken skins are possible ways to improve the safety and shelf life of the product although high levels of indigenous non-pathogenic bacteria may be beneficial due to their protective effect against potential re-contamination of chicken skin.

Influence of sodium chloride and pH during acidic marination on water retention and mechanical properties of turkey breast meat

Turkey breast cubes underwent acidic marination in the presence of salt. The transfer of water, salt and acid was measured, and texture was assessed on the cooked meat. While significant mass gains were observed during marination, from 20 minutes of immersion onwards, only long durations produced an overall matter balance greater than that of non-marinated meat. From the first minutes of immersion, these transfers caused hardening, regardless of the presence of salt in the marinade. For longer durations, only in the absence of salt was significant tenderizing seen in comparison to the non-marinated control. This effect appears to be due on the one hand to passing the isoelectric pH of the meat during acidification, and on the other hand to setting up antagonistic mechanisms breaking down or reinforcing connective tissues by acid and salt respectively. The high degree of tenderization observed in a water-acid solution can be explained partly by dilution of the fiber load per section unit due to protein solubilization.