advanced microbiology course - istanbul aydin university turkey

1. Food spoilage Strategies of prevention and new trends for preservation Microflora affecting food shelf-life GIOACCHINO dell'AQUILA – MODERN MICROBIOLOGY COURSE FOOD ENGINEERING MASTER DEGREE – ISTANBUL AYDIN UNIVERSITY, TURKEY

2. Precautions and measures adopted in production, processing, storage and distribution in order to obtain a safe, stable and tasty product suitable for human consumption

5. Why keeping food from spoilage? Deterioration leads to food wasting Contaminated food could be poisoning Money save keeping food from spoilage Unspoiled food retains also nourishing quality Ensuring availability of food

6. Where are microrganisms? - Soil and water - Plants and plant products - Air and dust - Animal hides - Gastro intestinal tract of animals and humans - Food handlers - Utensils and processing equipment

8. Microrganisms in food BACTERIA Pathogens Spoilage Probiotic FUNGI Yeasts Molds Manifacturing intended VIRUSES PARASITES – Micro and macrorganism

10. Factors affecting spoilage microflora Initial concentration Food texture, nutrient composition Acidity Time temperature ratio Redox potential Water activity

11. There are a wide range of metabolites produced during microbial spoilage including: • Alcohols • Sulphur compounds • Ketones • Hydrocarbons • Fluorescent pigments • Organic acids • Esters • Carbonyls • Diamines

12. Food categories Different food categories present several inhibition characteristics Cereals and bakery Dairy products Vegetables Fruit and Juices Fresh meat / Processed meat Fresh fish / Processed fish

16. Prevention of spoilage Managing temperature Managing water activity Managing oxygen presence Managing food formulation Accurate choice of processing technology Antimicrobial compounds

17. Managing temperature Inadequate processing results in spoilage by thermoduric and mesophillic spore forming bacteria Heat processing - Thermodurics: Clostridium, Bacillus, spores Pasteurisation - Thermodurics: Streptococcus, Lactobacillus, spores Chilled Storage - Psychrotrophs: Pseudomonas, Enterobacteriaceae, LAB, Micrococcus, Flavobacterium Most yeasts: Candida, Rhodotolura, Torulopsis Most moulds Frozen Storage - None grow, but Gram-positives and spores survive

19. Managing water activity Dried Food - Aw 0.6 Osmophilic yeasts and moulds Saccharomyces, Aspergillus Intermediate Moisture Food - Aw <0.85 Osmophilic yeasts and moulds, Staphylococcus Salt - Osmophiles, Micrococcus, Staphylococcus Sugar - Osmophiles

20. Managing oxygen presence Vacuum pa cking – Anaerobes, Microaerophiles Clostridium, Enterobacteraceae, LAB, Streptococcus, Bacillus; Some yeasts Carbon dioxide - Lactobacillus

21. Managing food composition Preservatives such as benzoate, sorbate, nitrites/nitrates, sulphure dioxide, chlorine, alcohol as far as they are effective do not avoid the growth of yeasts (e.g. Zygosaccharomyces bailii, Z. bysporus) , Pseudomonas fragi Saccharomyces cerevisiae, species of Escherichia coli and Lactobacillus acidophilus

22. TRIAS MANSILLA, R; (2008). Lactic acid bacteria as bioprotective agents against food borne pathogens and spoilage microrganisms in fresh fruit and vegetables

25. Choice of processing technology Thermal processing Water activity reduction Osmotic pressure Addition of preservatives Anaerobiosis Radiation Controlled atmosphere Asepsis Hurdles technique

27. High-pressure Leuconostoc mesenteroides has been evaluated in mango juice processed at 250 - 550 Mpa with an hold time 0 - 60 min at 20 – 25 °C. It is one of the most resistant spoilage bacteria; its complete destruction was achieved by a 5 min treatment at 400 MPa. For pathogenic Escherichia coli A 6- log reduction was observed at 400 MPa when treated for 10 min (at 500 and 550 MPa there were no survivors after the 1 min). Results showed that these processes were satisfactory because no further growth was observed during the entire storage time. HIREMATH, ND; RAMASWAMY, HS; (2011). High-pressure destruction kinetics of spoilage and pathogenic microorganisms in mango juice

28. Pulsed Electric Field Researchers at ARS/USDA (Agriculture Research Service / United States Department of Agriculture) Demonstrated that PEF treatment on salad dressings and apple juice Is effective on Lactobacillus plantarium. If additioned with mild heat treatment the shelf-life and sensory characteristics of food are retained for 470 days at room temperature McGINNIS, L; (2006). Non thermal processing is heating up. ARS, United States Department of Agriculture

37. What would be the strategy to ensure both a trustfull, stable and palatable food able to supply the market needs?

38. References PARFITT, J; BARTHEL, MACNAUGHTON, S; (2010). Food waste within food supply-chain: quantification and potential change to 2050 . SINGLETON, I; New Castle University (2011). Ozone reduces fungal spoilage of fruit and vegetables. NUNES BARBOSA, L, et al.; (2009). Essential Oils Against Foodborne Pathogens and Spoilage Bacteria in Minced Meat SHERMAN, P; BILLING, J; (1999). Darwinian gastronomy: Why we use spices ELLIN DOYL E, M; (2007). Microbial food spoilage. Losses and control strategies ELGAYYAR, M, et al ; (2001). Antinmicrobical activity of essential oils against selected pathogenic and saprophitic microorganisms. KISKO', G; ROLLER, S; (2005). Carvacrol and p -cymene inactivate Escherichia coli O157:H7 in apple juice. MUNDO, MA; PADILLA-ZAKOUR, OI; WOROBO, RW; (2004). Growth inhibition of foodborne pathogens and food spoilage organisms by select raw honeys MCHUGH, TH; WEN-XIAN DU, FRIEDMAN, M; (2008). For tomorrow's salads: plants extracts to conquer microbes. HIREMATH, ND; RAMASWAMY, HS; (2011). High-pressure destruction kinetics of spoilage and pathogenic microorganisms in mango juice RAYBAUDI-MASSILIA, RM; MOSQUEDA-MELGAR, J; SOLIVA-FORTUNY, R; MARTIN-BELLOSO, O ; (2009). Control of Pathogenic and Spoilage Microorganisms in Fresh-cut Fruits and Fruit Juices by Traditional and Alternative Natural Antimicrobials

40. Thank you for your attention!