High hydrostatic pressure (HHP) inactivation of foodborne pathogens in low‐acid juices

Abstract

Summary Consumption of unpasteurised fruit/vegetable juices has increased in recent years due to their freshness, low calorie contribution and good nutritional quality. However, unpasteurised fresh juices with low acidity (pH > 4.6) and high water activity (aw > 0.85) can support the growth of pathogens. Hence, pasteurisation is a necessary process in the production of low‐acid juices. Consumer demand has required minimally processed high‐quality foods that are free from additives, that are fresh tasting and microbiologically safe, and with an extended shelf life. High hydrostatic pressure (HHP) treatment is considered to be an alternative to thermal pasteurisation for fruit and vegetable juices. HHP treatment could preserve nutritional value and the sensory properties of fruits and vegetables due to its limited effect on the covalent bonds of low‐molecular‐mass compounds such as colour, flavour compounds and vitamins. However, inactivation of important foodborne pathogens in low‐acid foods by HHP is most urgent and critical. More research should be performed in order to satisfy consumer demands for fresh‐tasting products while retaining safety.

Effect of a winter savory leaf extract obtained using high hydrostatic pressure on the quality of carrot juice

“…Also, since its pH is close to neutral (Table 2), it should not majorly affect the biological activities of the bioactive compounds present in the winter savory extract, since also the extract has a pH ranging from 6.0 to 6.5. Due to these limitations, carrot juice must be consumed refrigerated, and no more than 1–2 days after production, a fact that greatly affects its marketability 1 . Hence, high‐pressure processing was used as a non‐thermal pasteurization technology to improve the juice microbiological stability (with or without the addition of winter savory extract), without the use of high temperatures, which could destroy nutrients and bioactive compounds, or even affect the juice organoleptic properties, such as colour and taste.…”

“…The consumption of vegetable juices has increased due to their premium characteristics such as freshness/naturalness, high nutritional value and low calorie content 1 . Carrot juice is one of the most consumed vegetable juices, but, when compared to other vegetable juices available on the market (such as tomato or beetroot), it has the lowest concentration of phenolic compounds and antioxidant activity 2 .…”

“…Raw carrot juice has a pH close to neutral (6.0–6.5) and a high water activity value ( a w > 0.85), indicating that it presents no natural barriers against the growth of both spoilage and pathogenic microorganisms, making its shelf‐life only 1–2 days under refrigeration 1 . To overcome this limitation, the food industry usually lowers its pH by the addition of acids or uses thermal processing to inactivate microbial growth and improve juice shelf‐life 6 .…”

Shelf‐life extension of multi‐vegetables smoothies by high‐pressure processing compared with thermal treatment. Part I: Microbial and enzyme inhibition, antioxidant status, and physical stability

“…The effectiveness of HPP has been demonstrated in several studies dealing with fruit juices, such as apple, orange, apricot, and cherry (Bayindirli, Alpas, Bozoğlu, & Hizal, ), pomegranate (Varela‐Santos et al, ), cape gooseberry pulp (Vega‐Gálvez et al, ), strawberry purée (Marszalek, Mitek, & Skapska, ), apple puree (Landl, Abadias, Sárraga, Viñas, & Picouet, ), multifruit smoothies (Hurtado et al, ), red‐fruits smoothies (Hurtado et al, , ), and in vegetable juices (Pilavtepe‐Celik, ), carrot juice (Kim, Park, Cho, & Park, ), cucumber juice (Zhao et al, ), sliced pumpkin (Zhou et al, ), or pumpkin purée (García‐Parra, González‐Cebrino, Delgado, Cava, & Ramírez, ). Most results concerning the microbiological inactivation by pressurization refer to acidic products, including fruit juices.…”

Effect of cold-pressed and normal centrifugal juicing on quality attributes of fresh juices: do cold-pressed juices harbor a superior nutritional quality and antioxidant capacity?

“…Over the past few years, there is an ever-growing demand for the consumption of freshly prepared unpasteurized fruit juices with no or minimal processing, due to its freshness, higher vitamin content, and high nutritional value. Traditional thermal treatments, including pasteurization adversely affect the nutritional values and sensory characteristics of foods and beverages (Wolbang et al., 2008; Rawson et al., 2011; Pilavtepe-Celik, 2013), and sometimes fail to produce a microbiologically stable product (Mohamed and Eissa, 2012). Cold-pressed juices have been introduced as a new generation of fruit beverages and are claimed by beverage manufacturers to have higher contents of bioactive compounds compared to those of regular (normal) centrifugal juices (The wonderful benefits of cold Pressed Juice, 2018; The real benefits of cold-pressed juice, 2018).…”