Deliv­er­ing healthy food with high nutri­tional value and plenty of flavor

An orange juice or straw­berry shake as a healthy refresh­ment between meals: prac­ti­cally portioned, sustain­ably pack­aged, a long shelf life and safe to consume – increas­ing customer demands on food and bever­age pack­ag­ing are constantly confronting manu­fac­tur­ers with new chal­lenges. After all, consumers wish to fit read­ily avail­able meals into their daily routines. At the same time, their aware­ness of the envi­ron­ment and a healthy, sustain­able lifestyle is increasing.

However, bever­ages like milk, fruit juices or non-carbon­ated soft drinks will spoil within a few days if not chilled during trans­ported and stor­age. Refrig­er­a­tion needs energy and has a nega­tive envi­ron­men­tal impact. But if a yoghurt drink no longer tastes fresh or is even spoiled, it quickly ends up in the trash can. Some eleven million tons of food are thrown away every year just in German house­holds. Accord­ing to a report by the Federal Ministry of Food and Agri­cul­ture, six million CO₂-equiv­a­lent tons of green­house gas emis­sions could be saved in Germany if this waste were to be halved.

Safe food

An esti­mate by the World Health Orga­ni­za­tion (WHO) shows how impor­tant safe food is. Accord­ing to this, every tenth person world­wide falls ill each year as a result of consum­ing cont­a­m­i­nated food. Germ-free pack­ag­ing can protect contents from spoil­ing along the entire supply chain. This way, food supply can be ensured, even in regions with less infra­struc­ture and extreme temperatures.

Nonper­ish­able with­out involv­ing refrig­er­a­tion and preservatives

Bever­age and dairy manu­fac­tur­ers are there­fore search­ing for solu­tions that enable them to pack, trans­port, and store food ecolog­i­cally, econom­i­cally and safely, while keep­ing it fresh for as long as possi­ble. In line with consumer demands, these compa­nies are increas­ingly focus­ing on sustain­abil­ity and recy­cling management.

A partic­u­larly effi­cient and sustain­able solu­tion is asep­tic pack­ag­ing in bever­age cartons and plas­tic bottles. This method involves cartons or bottles being ster­il­ized and – once the heat-treated prod­uct has been filled in – sealed under asep­tic condi­tions. The bever­ages or milk prod­ucts can then be stored for much longer peri­ods – even at ambi­ent, with­out involv­ing energy-inten­sive refrig­er­a­tion and preservatives.

In the past, pack­ag­ing was ther­mally ster­il­ized, but this method consumes a great deal of energy. However, the asep­tic method using oxidants like hydro­gen perox­ide (H₂O₂) or peracetic acid (PAA) has long since taken root, for tech­ni­cal and economic reasons.

However, perox­ides are excel­lent perform­ers, partic­u­larly in sustain­abil­ity terms. These potent ster­il­iz­ing agents do not release any envi­ron­men­tally harm­ful substances when react­ing and are there­fore not harm­ful to humans and the natural world. Hydro­gen perox­ide breaks down into oxygen and water, while peracetic acid breaks down into acetic acid (vine­gar) and hydro­gen perox­ide, and the latter in turn into oxygen and water.

“After test­ing and trying out differ­ent prod­ucts and tech­nolo­gies, the market has decided that disin­fec­tion using perox­ides is the best solu­tion for achiev­ing asep­tic food pack­ag­ing,” says Jacobo Villa­gran, Market­ing Manager Asep­tic Pack­ag­ing & Envi­ron­men­tal at Evonik Active Oxygens. The company manu­fac­tures and markets these chem­i­cals under the OXTERIL®, CLAR­ITY®, and PERA­CLEAN® brand names.

Envi­ron­men­tal bene­fits of asep­tic pack­ag­ing ster­il­ized with H₂O₂ or PAA

• Energy-effi­cient ster­il­iza­tion with no harm­ful by-products
• Preserv­ing nutri­tional and organolep­tic values of shelf-stable prod­ucts with­out the need for refrigeration
• Lower costs and energy consumption
• Foods with longer shelf lives help to conserve resources

Germ-free with the aid of hydro­gen perox­ide and peracetic acid sterilants

There are essen­tially two tech­nolo­gies using hydro­gen perox­ide for killing off germs in pack­ag­ing: bath ster­il­iza­tion, where the pack­ag­ing is immersed in a bath of H₂O₂ solu­tion, and vapor ster­il­iza­tion, where the bever­age container is ster­il­ized with a blow of vapor­ized hydro­gen perox­ide. Each method requires special grades of H₂O₂, contain­ing differ­ent quan­ti­ties of stabi­liz­ers to ensure the asep­tic ster­il­iza­tion and fill­ing process works safely and effectively.

“These stabi­liz­ers have to be used spar­ingly and with care,” Villa­gran explains. “That is because in the case of the spray method, an exces­sive quan­tity of stabi­liz­ers can clog up and block the spray nozzles.” That disrupts processes and is there­fore unsus­tain­able and not cost-effective.

Peracetic acid is mainly used to ster­il­ize plas­tic bottles. In partic­u­lar, PET bottles are becom­ing increas­ingly popu­lar with both manu­fac­tur­ers and consumers, because they are light­weight and can be recy­cled. Peracetic acid is a stronger oxidant than hydro­gen perox­ide, and ster­il­izes effec­tively even at low temper­a­tures. As plas­tic bottles can shrink at high temper­a­tures, peracetic acid is there­fore more suit­able in this instance.

Tech­no­log­i­cal tran­si­tion from PAA to H₂O₂

There are also differ­ent meth­ods for ster­il­iza­tion of PET bottles. One method is using liquid peracetic acid solu­tion, which liquid peracetic acid is sprayed under high pres­sure onto bottles and rinsed out with ster­ile water.

“In recent years, however, tech­nol­ogy has increas­ingly shifted from ster­il­iza­tion of bottles to ster­il­iza­tion of Preforms. PET bottles are blow-molded from so-called preforms – a small thick version of the bottle. Vapor­ised hydro­gen perox­ide (VHP) works very well on these preforms thanks to the thick­ness making the preforms more resis­tant to heat and shrink­age. The VHP ster­il­iza­tion doesn’t require water rinse and greatly reduces ster­i­lant and water usage provid­ing for envi­ron­men­tally friendly process,” says Pavel Korzinek, Busi­ness Segment Manager Asep­tic Pack­ag­ing at Evonik Active Oxygens.

Evonik is devel­op­ing premium H₂O₂ and PAA grades for more effi­cient manufacturing

Oper­at­ing speeds and output of asep­tic bever­age filing lines have been increas­ing rapidly. Some of these high-speed asep­tic machines can fill 50,000 or more bottles or bever­age cartons an hour. As a result, demands on the qual­ity of ster­i­lants are also increasing.

To address these needs, Evonik Active Oxygens, in part­ner­ship with machine manu­fac­tur­ers (OEMs), is contin­u­ously work­ing on devel­op­ment of specialty grades of hydro­gen perox­ide and peracetic acid ster­i­lants, and advanced more effi­cient ster­il­iza­tion tech­nolo­gies for their application.

The pack­ag­ing indus­try as well as manu­fac­tur­ers of asep­tic systems are also focus­ing increas­ingly on sustain­abil­ity and invest­ing in asep­tic pack­ag­ing that can be recy­cled and protects the envi­ron­ment. To ensure that refresh­ing bever­ages are not only safely pack­aged and retain their flavor over long peri­ods, but also to ensure that valu­able resources are conserved during production.