Managing microbes

Food Science and TechnologyVolume 35, Issue 3 p. 58-61 FeaturesFree Access Managing microbes First published: 16 September 2021 https://doi.org/10.1002/fsat.3503_15.xAboutSectionsPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text full-text accessPlease review our Terms Conditions of Use check box below share version article.I have read accept the Wiley Online Library UseShareable LinkUse link a this article with your friends colleagues. Learn more.Copy URL Share linkShare onFacebookTwitterLinked InRedditWechat Nick Meakin Aqualution Systems discusses management microbial pathogens spoilage organisms in vegetable, salad, herb fruit processing using new hypochlorous acid decontamination process. Background Globally, production fruits, vegetables, salads herbs is increasing rapidly, driven by rising middle-class populations, an upsurge disposable income, rapid urbanisation, changing consumer lifestyles growing awareness importance healthy diet. The prepared produce vital part producing safe ready-to-eat minimally processed food also designed prevent cross contamination improve shelf life. Whilst processes isolation do not guarantee that totally free from foreign bodies, they are validated reduce residual loadings infective dose level. A number approved UK retailers adopted globally supply chain, each its pros cons. most common methods based on immersion agitated water, often biocidal aid. Risk assessments typically undertaken factory question determine right protocol for maximum protection. Factors taken into consideration include ease opportunity pathogen organism as well risk posed operators handling chemicals. popular standard use ‘chlorine-based’ systems, term ‘chlorine’ used describe products generated acidification sodium hypochlorite. Innovation within retailer-approved range was limited until chlorate residues fruits vegetables became issue 2014, when voluntarily withdrawn EU market plant protection product because cost compliance regulation never going be recovered size potential market. As result, established residue limits (MRL) were limit 0.01mg/kg came force default, highlighting one biggest drawbacks conventional acidified hypochlorite-based process, namely consequential produce. European Safety Authority (EFSA) has continued evaluate levels drinking water foods after years consultation evaluation, Commission published regulations 2020, allowed level being specified majority (Table 1). Table 1. Examples (Commission Regulation (EU) 2020/749) Product Chlorate MRL (mg/kg) Fruit Stone/pome/citrus/berries/grapes 0.05 Olives 0.7 Other edible peel e.g. figs 0.3 Inedible kiwi Vegetables/salad/herbs Leafy veg spinach/herbs Broccoli 0.4 Beans/Peas/Lentils without pods 0.35 roots beets 0.15 Tomatoes 0.1 Aubergines pumpkin 0.08 Edible cucumber 0.2 Chlorine disinfection water-based systems However solution generated, whether dissolving chlorine gas diluting liquid bleach (sodium hypochlorite), or powdered (calcium chemistry function pH. resulting will mixture chlorine, hypochlorite (Figure Figure 1Open figure viewerPowerPoint effect pH species Hypochlorous (HOCl) effective known biocides. This weak first chemical produced mammalian immune system kill invasive fight infection highly at relatively low concentrations. HOCl does dissociate whereas does, OCL- ion active. Depending organic load present, up 100 times more biocide than same concentration OCl-; 1ppm many 100ppm OCL-. very fast acting compared actives, requiring far shortest contact achieve 99.9999% pathogens, time just 0.55 seconds1 E coli example. able all hierarchical scale susceptibility 2) Spores can inactivated 150ppm between minute (Bacillus subtilis) five minutes (Clostridium difficile). By comparison, 1000ppm required Clostridium difficile spores minutes. 2Open Susceptibility different disinfectants Disadvantages For decontamination, around used; approximately 7.8 comprises 30ppm 70ppm OCl-2. Citric then added further usually 7.5, which point contains 50ppm delivered robust reproducible However, loss forced re-assessment likelihood by-products created remaining Contrary belief, by-product systems. Sodium stable molecule degradation product. decays, some oxygen gases off (explaining why drum expand storage) converted salt chloride). kinetics reactions complex but investigated Lister et al. 1950’s3, who identified following reactions: 2 NaOCl → NaCI + NaC 1 O NaOCI NaCl NaCIO Consequently, making two-three-month-old hypochlorite, potentially 10% could 1-2mg/kg. offers alternative To address problems associated Systems, science-led Scottish company spun out pharmaceutical 2009, developed technology deliver pure healthcare processing. originally Marks & Spencer Campden BRI, enables well-established benefits chlorine-based yet overcomes toxicity All biocides must comply requirements (EU528/2012) supplier provide audit trail demonstrate active(s) and/or precursors formulation been sourced 95 list substance suppliers correct type. Aqualution's compliant above regulation, having submitted now active dossiers authorising purposes (and post Brexit). Commission's SUSCLEAN (Sustainable Cleaning Disinfection Fresh-Cut Industries 2014) project acid-based found it only evaluated both microbially economically viable. study demonstrated test unit installed salad Portugal, addition delivering on-site reduction energy consumption, showed less corrosive 30% wash4. process design 3) uses in-situ generators 4) biocide, automatically dosed flume where decontaminated via combination jacuzzi agitation treatment. Typically, 20-40ppm (measured chlorine) wash adequate. reduced once there confidence stability controls; currently working partner 10ppm. Full automated QC monitoring remote access if required. 3Open Diagram 4Open operational countries providing wide including beans, onions, cherries, raspberries, strawberries, broccoli, pak choi herbs. about install UK, targeted decontamination. retro fitted existing fully scalable. largest so consumption >1m litres per day. Design bespoke installation factory, produce, source any pre-wash processes, optimise quality safety, along commercial benefit. example, whilst raspberries require dry fogging prior packing ensure virus cherries need cooled rapidly hydrocooler harvesting otherwise may split. pumped Recycling through (Figures 5 6) enhances action, physically removing micro-organisms easier no longer protected biofilms, allowing reduced. vortex flow multi-media filter sieve 0.4μ coming allows recycled back next batch 5Open Beans 6Open Baby leaf Advantages decontaminate fresh Pathogen rate Validation comparison trials cases, improved reducing poisoning supporting recycling converts static bath continuous and, jet flows 10,000 hour, physical removal microorganisms 2). 2. log Flow Rate Free available Log (litres/h) (ppm) Static 37 1.1 1,500 18 1.5 Solving problem degrade (a co-formulant) manufacture 1% advantage on-site, demand solution, always 24 hours old. At recommended dosing rates, consistently detection. results three immediate benefits. Firstly, (or other by-product) issues. Secondly, unlike almost biocides, lack concern permits leading significant reductions consumption. Tirdly, precursor generate acid, significantly 50% 7.5 trial carried diced beans (typically worst case retention) washed various concentrations order onto 20ppm, detection even 160ppm flume, 0.35mg/kg 3). 3. Sample type Perchlorate 0.840 < 0.01 55ppm 0.220 22ppm 0.060 Diced (160ppm) 0.030 (55ppm) 0.014 (22ppm) ND Control Unwashed (Kenya) Continuous usage Unlike discarded several day due decay build up, chlorates present concern. An additional benefit transformed yielding productivity current installations 25-30%. vegetable packhouse Kenya 7) since 2013 consumes 100,000 week four tonnes hour day, six days week. previous consumed over 500,000 week, effluent generation 400,000 Across global operations, average 80%. 7Open built (1,000 litre 60kg min time) 4 Reduction Existing acidify numbers contaminating produces 99.6% halved. Pumping filter, recycle re-dose effectiveness permitting while maintaining desired reductions. Trial possible equivalent those obtained 90ppm lower (29ppm)4. chemicals health employees. Because operates flumes, strong ‘bleach’ smell prevalent eliminated. Reduced electricity system, volume chilled needed operate Once cold, requires little power keep pick much heat flowing 1°C). powering chillers 85%. 6 Improved life During shown washing had impact growth product4.User experience suggests Conclusions becoming gold-standard across world protocols codes practice supermarkets. Not proven pathogenic microbes, terms electricity, extending shelf-life. Meakin, CEO, Ltd, Duns, Scotland Email [email protected] Web aqualution.co.uk/ References 1Albrich, J.M., Hurst, J.K. 1982. Oxidation inactivation E. acid. Federation Biochemical Societies Letters 144: 157- 161Google Scholar 2Bowman, G., Mealy, R. 2007. fundamentals disinfection. Wisconsin State Laboratory Hygiene Google 3Lister, M.W. 1956. Decomposition hypochclorite: uncatalyzed reaction. Canadian Journal Chemistry, https://doi.org/10.1139/v56-068Google 4Machada 2016. neutral electrolyzed oxidizing biofilm regrowth fresh-cut vegetables. University Porto, Bioproducts Processing; Susclean WP3 WP4 feedback presentation, Dec 2014 Volume35, Issue3September 2021Pages FiguresReferencesRelatedInformation