Target Selection in Designing Pasteurization Processes for Shelf-Stable High-Acid Fruit Products

Abstract

This study is focused on the search for targets and criteria for the design of pasteurization processes for high-acid shelf-stable fruit products, such as juices, nectars, pastes, purees, concentrates, jams, jellies, etc. First, an overview of pasteurization is presented and then, frequently used targets for pasteurization processes are reviewed Enzymes naturally present in fruits, in decreasing order of heat resistance, were pectinesterase, peroxidase, and polyphenoloxidase, and they may be used as pasteurization targets. The heat resistance of each enzyme is strongly dependent on its fruit origin. The most heat resistant micro-organisms capable of spoiling high acid fruit products include ascospores of Neosartorya fischeri, Byssochlamys nivea, Talaromyces flavus, Eupenicillium javanicum, and Byssochlamys fulva moulds, as well as bacterial spores of Clostridium butyricum, Bacillus coagulans, and Bacillus megaterium. These micro-organisms, spores, and enzymes were, in general, less heat resistant than the spores of a particular spoilage micro-organism named Alicyclobacillus acidoterrestris, which has been causing problems in the fruit industry. Therefore, the use of Alicyclobacillus acidoterrestris spores as a reference micro-organism in the design of pasteurization processes for high-acid shelf-stable fruit products is suggested.

Pasteurization of citrus juices with ohmic heating to preserve the carotenoid profile

“…These pasteurization values are in accordance with that proposed by Tucker (2011) (Tucker & Featherstone, 2011). A z-value of 10°C was chosen because it is in the range of 8-11°C-values of spoilage micro-organisms in high-acid fruit products (Silva & Gibbs, 2004) Pasteurization value (P) is the equivalent time in min at T ref obtained from the timetemperature curve of a product during a heat process to evaluate a pasteurizing process according to eq (1):…”

Contamination of pear concentrate by Alicyclobacillus from recirculating flume water during fruit concentrate production

“…Most acid tolerant potential spoilage microbes have a low heat resistance and their vegetative forms will be inactivated by pasteurization treatments under 100°C for relatively short times (Silva and Gibbs 2004). This was evident as evaporation of single strength juice resulted in a decrease in viable aerobic counts from 4.61 to 3.54 Log 10 c.f.u.…”

“…Alicyclobacilli are thermo-acidophilic, non-pathogenic, endospore-forming bacteria and have the ability to survive thermal processing applied during the production of highacid concentrated fruit products (pH \ 4.0) (Wisotzkey et al 1992;Silva and Gibbs 2004;Ceviz et al 2009). The increasing occurrence of Alicyclobacillus in fruit beverages are a concern for the industry since beverage bases (fruit concentrates, syrups, pulps and purees) are generally considered commercially sterile and have significantly improved transportation and storage properties (Chen et al 2006;Maldonado et al 2008;Walker and Phillips 2008;Durak et al 2010) Although the soluble solid content ([20°Brix) of concentrated fruit products inhibit the germination of Alicyclobacillus endospores (Splittstoesser et al 1994;Chang and Kang 2004), these endospores retain their viability which upon dilution to single strength could reach adequate conditions for growth and spoilage to occur (Borlinghaus and Engel 1997;Ceviz et al 2009).…”

Quality changes of pasteurised mango juice during storage. Part I: Selecting shelf-life markers by integration of a targeted and untargeted multivariate approach

“…As a seasonal and highly perishable commodity, mango fruit is commonly processed into different products to extend its shelf-life. By applying conventional thermal treatment, such as pasteurisation, a high-acid food product (pH < 4.6) is microbiologically safe, thus can be stored at ambient temperature for a long period (Rawson et al, 2011;Silva & Gibbs, 2004). A number of thermally-treated mango products which are available in the market are mango jam, puree, nectar, juice and canned slices (Siddiq,Akhtar,5 The objective of this work is to study the quality changes of pasteurised, shelf-stable mango juice as a function of shelf-life.…”