“Bacalaos Alkorta” achievements with high pressure processing (HPP)

Cod is amongst the most demanded fish in Europe due its nutritious, lean meat, and unique taste. Bacalaos Alkorta, one of the cod processing leaders around the world, identified the potential safety hazards and time investment during the desalting step although the shelf life of desalted cod is just within 3-7 days with proper handling and refrigeration. Thus, Bacalaos Alkorta decided to invest in the HPP technology for safety and shelf life extension, without comprising the quality of cod. Bacalaos Alkorta recently launched HPP cod loins, fillet crumbles, and Basque cuisine delicacy “kokotxas” (cod jowl), with enhanced safety and high product quality. This way, Bacalos Alkorta proudly steps into the HPP family with very interesting commercial applications, in the always challenging seafood sector.

Unsalted Cod

Cod is the most consumed fish in Europe, and used in a number of dishes in the traditional Spaniard and Norwegian cuisine. Cod flesh is nutritious, with a high protein content, lean but containing healthy Omega-3 fatty acids, and rich in minerals (Tu España, 2019). In Europe, cod is consumed fresh during spawn season (January-April) and coastal cities throughout the year. On the other hand, salting cod makes the fish available throughout the year, providing a different but highly appreciated sensory experience (Andrés et al. 2005; La Española Aceites, 2019).

The traditional “stack or pile salting” method piles up alternate layers of cod fillets and dry salt crystals to yield a 20% (w/w) salt concentration (Andrés et al., 2005; Barat et al., 2003). The process takes between 2-8 weeks, depending on the overpressure exerted by the weight of each pile and the desired sensory properties. Industry processors also perform cod salting by submerging the fish in brine solutions at 5 °C for 15 days or more with a 1:1 salt to cod ratio (Andrés et al., 2005; Barat et al., 2003). Alternatively, brine salting serves as a pre-treatment step followed by stack salting (Nguyen et al. 2010). A drying step usually follows cod salting, allowing meat to remain shelf stable during several months.

Before cooking, submerging cod in fresh, chilled water between 1-3 days and changing water every 6-8 hours to rehydrate meat and remove excess salt, to yield “unsalted” cod. Nonetheless, potential safety or spoilage issues may arise during desalting due to improper handling, contamination of desalting water, or temperature abuse. In example, Barat et al. (2006) observed that the total aerobic counts remained between 2.5-3.5 log10 cfu/g after desalting, and the microbial load reached ~7 log10 cfu/g after 6 days in refrigeration at 4 °C.

Bacalaos Alkorta and HPP

Bacalaos Alkorta S.L is a Basque fishery established in 1976 by Miguel Angel Alkorta and José Ignacio Alkorta, and the company decided to focus solely on cod processing since 1999. Nowadays, Bakalos Alkorta facilities comprise 3,700 m2 (~39,800 ft2) destined to the production of salted, unsalted, and frozen cod. As a leader cod processor, Bacalaos Alkorta identified the risk and time consumption associated with cod unsalting, and decided to provide customers with a more convenient, safe, and high quality unsalted cod.

In this regard, Bacalos Alkorta explored high pressure processing (HPP) as an alternative since the technology is worldwide regarded for providing safe and clean label foods, with premium nutritional and sensorial quality.

They have also worked closely with Hiperbaric and Accua HPP Solutions to develop an appropriate process for their products and implement it in an industrial level in a safe and reliable way.

Time and resources invested by Bacalaos Alkorta paid off with the launching of different unsalted cod products such as loins, fillet crumbles, and Basque cuisine delicacy “kokotxas” (cod jowl) shown in Fig. 1.

Figure 1. Bacalos Alkorta HPP cod products: (a) loin; (b) fillet crumbles; (c) “Kokotxas” (cod jowl).

Figure 1. Bacalos Alkorta HPP cod products: (a) loin; (b) fillet crumbles; (c) “Kokotxas” (cod jowl).

Commercial HPP ready-to-cook products by Bacalao Alkorta may be found conveniently vacuum skin-packaged in trays, saving consumers time associated with cod unsalting while improving safety and extending shelf life by processing around 5,000-6,000 bar (72,500-87,000 psi). The image below shows no difference between untreated and HPP unsalted cod samples, allowing unsalted cod samples to retain the traditional white color.

Figure 2. Effect of HPP cod fish samples. Source: Hiperbaric Applications and Food Processing.

Figure 2. Effect of HPP cod fish samples. Source: Hiperbaric Applications and Food Processing.

The HPP technology could also serve as a shelf life extension in fresh cod (Fig. 3), although color change occurs in fresh fish and meat products. Fresh cod fillets acquired an opaque white appearance around 2,000-3,000 bar (29,400-58,800 psi) according to Arnaud et al. (2017). Nonetheless, pressure levels above 3,000 bar (44,100 psi) are required to slow down microbial growth and achieve shelf life extension. Processing at 4,500 bar (66,200 psi) during 5 min resulted in non-detectable levels of the total plate count after 14 days in refrigerated storage (4 °C; Fig. 3a). Increasing pressure level to 5,500 bar (80,850 psi) controlled psycrotrophic bacteria growth during 28 days and no rancid flavors associated with lipid oxidation were reported after 18 days (Rode & Hovda, 2016).

Figure 3. (a) Effect of pressure level (5 min holding time) on the microbial load of fresh cod fillets. Data from Arnaud et al. (2017). (b) Psycrotrophic bacteria growth in untreated and HPP fresh cod samples. Data from Rode & Hovda (2016).

Figure 3. (a) Effect of pressure level (5 min holding time) on the microbial load of fresh cod fillets. Data from Arnaud et al. (2017). (b) Psycrotrophic bacteria growth in untreated and HPP fresh cod samples. Data from Rode & Hovda (2016).

Conversely, the white appearance of unsalted cod meat does not experience alterations under high pressure (Fig. 2), allowing to apply pressure levels between 5,000-6,000 bar (72,500-87,000 psi) to further extend shelf life.

Hiperbaric At Your Service

Hiperbaric is the world leader manufacturer of High Pressure Processing (HPP) equipment we support companies that use the technology. If you would like to learn more about HPP food processing do not hesitate to reach out.

Consulted References

Andrés, A., Rodríguez-Barona, S., Barat, J. M., & Fito, P. (2005). Salted cod manufacturing: influence of salting procedure on process yield and product characteristics. Journal of Food Engineering, 69(4), 467-471. doi:https://doi.org/10.1016/j.jfoodeng.2004.08.040

Arnaud, C., de Lamballerie, M., & Pottier, L. (2018). Effect of high pressure processing on the preservation of frozen and re-thawed sliced cod (Gadus morhua) and salmon (Salmo salar) fillets. High Pressure Research, 38(1), 62-79. doi:10.1080/08957959.2017.1399372

Barat, J. M., Gallart-Jornet, L., Andrés, A., Akse, L., Carlehög, M., & Skjerdal, O. T. (2006). Influence of cod freshness on the salting, drying and desalting stages. Journal of Food Engineering, 73(1), 9-19. doi:https://doi.org/10.1016/j.jfoodeng.2004.12.023

La Española Aceites. (2019). El bacalao: propiedades y formas de prepararlo, un salado muy sabroso.

Nguyen, M. V., Arason, S., Thorarinsdottir, K. A., Thorkelsson, G., & Gudmundsdóttir, A. (2010). Influence of salt concentration on the salting kinetics of cod loin (Gadus morhua) during brine salting. Journal of Food Engineering, 100(2), 225-231. doi:https://doi.org/10.1016/j.jfoodeng.2010.04.003

Tu España. (2019). Bacalao.   Retrieved from https://www.spain.info/es/que-quieres/gastronomia/productos/bacalao.html

Rode, T. M., & Hovda, M. B. (2016). High pressure processing extend the shelf life of fresh salmon, cod and mackerel. Food Control, 70, 242-248. doi:http://dx.doi.org/10.1016/j.foodcont.2016.05.045

Truong, B. Q., Buckow, R., Stathopoulos, C. E., & Nguyen, M. H. (2015). Advances in high-pressure processing of fish muscles. Food Engineering Reviews, 7(2), 109-129. doi:10.1007/s12393-014-9084-9

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