HPP effects toward the food products quality and microbial food safety

From the previous posts, we already know that High-pressure processing (HPP) is a non-thermal process capable of inactivating and eliminating pathogenic and food spoilage microorganisms.

In this post we will look at effect of the method towards the food product;

Microbial Food Safety

Different species of microorganism has different degrees of resistance as well as various sensitivity towards High-pressure-processing treatment (Alpas H, Kalchayanand N, Bozoglu F, Sikes A, 1999).

• It is well established that bacterial endospores are the most-pressure resistant life forms known (Farkas & Hoover, n.d.)

• Pathogen found which is the most heat –resistant and most lethal to human being is C.botulinum primarilytypes A,B,E and F. C.botulinum is the most pressure-resistant and dangerous organism faced by HPP (Farkas & Hoover, n.d.).

• Gram-positive bacteria are more resistant to heat and pressure than gram-negative bacteria (Smelt, 1998)

• Cocci-shaped bacteria are more resistant than rod-shaped bacteria (Smelt, 1998)

• Non-sporeforming gram-positive bacteria , Staphyloccocus aureus have a high resistance to pressure (Smelt, 1998) .

• Organisms with simpler structure such as bacteria was found to be more resistant to HPP inactivation (Farkas & Hoover, n.d.).

• HPP is said to be effective in eliminating foodborne parasites, such as Toxoplasma gondii, Cryptosporidium parvum, Anisakis simplex, Trichinella spiralis and Ascaris, in low pressure ranges (Farkas & Hoover, n.d.).

•  Moulds and yeast have intermediate resistance with mould mycelia being particularly susceptible but mould spores that are quite resistant to HPP have been reported (Farkas & Hoover, n.d.).

   FOOD QUALITY

•      Produce high-quality foods that display characteristics of fresh products, are microbiologically safe and have an extended shelf life (Hogan et al., 2005; Patterson, 2005) while retaining the sensory characteristics of fresh food products (Patterson, 2005)
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•      Changes in physical functionality and/or changes in raw product colour are significantly less than those experienced using conventional thermal processing techniques (Hogan et al., 2005).
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•      The physical structure of most highmoisture food products remains unchanged after HPP exposure as the pressure exerted does not generate shear forces (Hogan et al., 2005); however, colour and texture may change in gas-containing products post-HPP treatment due to gas displacement and liquid infiltration into the collapsed
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•      Product yield is of immense economic importance to food manufacturers and HPP treatment in general gives a higher food product yield compared with heat treatment, with effects depending on product type and treatment intensity (Hugas et al., 2002).