Post-processing Technologies

Transcription

1 Post-processing Technologies to Control L. monocytogenes in RTE Meats Lynn M. McMullenM Department of Agricultural, Food and Nutritional Science University it of Alberta

2 Post-processing technologies to control L. monocytogenes in RTE meats Not a replacement for GMPs

3 Post-processing technologies Thermal: Thermal pasteurization Non thermal Irradiation High pressure processing Biopreservation Chemical antimicrobials

4 High Pressure Processing Destroy cell membranes cell permeability transport systems Homoeostasis Cellular l proteins Enzymes Limited impact on quality of RTE foods

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6 pressure Inactivation of Vegetative Cells by High Hydrostatic Pressure Denaturation of proteins, Inactivation of bacteria Piezophysiology : Stress reaction on metabolic level Growth inhibition, stress reaction on transcriptional and translational levels

7 Pressure Effects on Listeria i monocytogenes Pressure typically 300 to 600 MPa Time typically 2 to 10 min Temperature Greater temperature, greater efficacy

8 Effect of temperature on pressure inactivation of L. monocytogenes in ready-to-eat tturkey breast. Chen 2007 Int. J. Food Microbiol. 117:55

9 Survival of L. monocytogenes on turkey breast treated at 300 MPa and 55 C, 400 MPa aand d50 C, and 500 MPa and 40 C. Chen 2007 Int. J. Food Microbiol. 117:55

10 Behaviour of L. monocytogenes on HPP-treated sliced cooked ham during storage at 6ºC 0 MPA 400 MPA 600 MPA Aymerich et al., 2008 Meat Sci 76:114

11 Pressure Effects on Listeria i monocytogenes Pressure typically y 300 to 600 MPa Time typically 2 to 10 min Temperature Composition of food Carbohydrate, fat, protein = protective effects??? Decrease (log CFU) in L. innocua CTC1014 after HPP (500 MPa, 40ºC 10 min) in: phosphate buffer cooked ham slurry

12 Log (N/NO) Efficacy of HPP L. monocytogenes, 20ºC, 375 MPa Raw chicken meat Phosphate buffered saline, ph Time (min) Patterson et al., J Food Protect 58:524

13 Pressure Effects on Listeria i monocytogenes Pressure typically y 300 to 600 MPa Time typically 2 to 10 min Temperature Composition of food ph Water activity lower a w = more resistant Strain variation

14 Variation in pressure resistance within species of L. monocytogenes Compilation of data on pressure resistance of L. monocytogenes (6 strains each represented by different symbols). Conditions of pressurization are similar (Garcia et al., 2002) Pressure processes should target the MOST RESISTANT representative

15 Elimination of L. monocytogenes Product in foods Heat Required treatment Pressure Non-acid food, Long storage 70ºC / 2 min 600 MPa life >50ºC Intensity of pressure treatment may be reduced by combination with further stress factors (ph, antimicrobials, etc) and controlled storage to eliminate sublethally injured cells.

16 Impact of HPP on consumer acceptability of low fat pastrami stored at 4ºC Untreated day 7 HPP day 47 HPP day 77 Mea an accep ptability score Appearance Aroma Flavour Overall liking Hayman et al., J Food Protect 67:1709

17 HPP as an Intervention for Pasteurization Processed Meats 600 MPa, >50ºC require hurdles for spore formers Sterilization ti >600 MPa, high temperature needed

18 Post Packaging Pasteurization In package, thermal process Whole deli products to sliced products Variation in surfaces along single product Temperature profiles with sliced products

19 Conditions for PPP Temperature: range from 70 to 96ºC Dwell time: range from 30 sec to 10 min.

20 Effect of thermal pasteurization on survival of L. monocytogenes Efficacy is dependent on: Temperature Duration Product

21 Reduction in L. monocytogenes on the surface of vacuum packaged, smoked ham 96.1ºC subjected to 90.6ºC submersion heating 93.3ºC Muriana et al., J Food Protect 65:963

22 Reduction in L. monocytogenes on the surface of vacuum packaged, skin-on turkey subjected to submersion heating 96.1ºC 90.6ºC 93.3ºC Muriana et al., J Food Protect 65:963

23 Reduction of L. monocytogenes on various specialty deli turkey products at 200ºF (93.3 (933ºC; ) and 205ºF (96.1ºC; (961ºC ) Turkey-ham Cracked pepper turkey Muriana et al., J Food Protect 65:963

24 Effect of a low acid liquid smoke dip and submersion heating (93ºC) on the growth of L. monocytogenes on deli turkey stored at 6.1ºC 10 Log CFU U/ml rinse Control 60 sec heat Smk + 0 sec heat Smk + 15 sec heat Smk + 30 sec heat Smk + 60 sec heat Time (weeks) Gedela et al., J Food Protect 70:2749

25 Effect of potassium lactate/sodium diacetate and submersion heating (96ºC for 3 min) on the growth of L. monocytogenes on turkey breast stored at 4ºC Control Log CFU U/package Klac/DA Control+ heat Klac/DA+heat Time (days) Gedela et al., J Food Protect 70:2749

26 Impact of thermal treatments on reduction of L. monocytogenes Product Process Temp p( (ºC) time Log reduction Roast submersion 96 5 min 4.5 beef Hot dog steam 85 to 95 4 to 8 min 4 to 5 Hot dog pressurized sec 3 steam, prepack with continuous system

27 Impact of PPP on Expressible Moisture Fully cooked vacuum packaged chicken breast strips Treatment Time (min) % expressible moisture Hot water Hot water Steam Steam Control Expressible moisture = water holding Murphy and Berrang J Food Sci 67:2325

28 Post-packaging Pasteurization Alone limited efficacy Alternative 2 Surface properties, product size important In combination with other antimicrobials Depends on antimicrobial Not all are effective in controlling growth

29 Biopreservation Extended storage life and enhanced safety of foods using the natural microflora and/or their antibacterial products Application in food: 1. use bacterial strains 2. add purified substance 3. add fermentation liquor or concentrate

30 Acids Multiple Antimicrobial Effects of Lactic Acid Bacteria Lactate, acetate, formate Diacetyl, acetaldehyde Reuterin = aldehyde Bacteriocins i Antimicrobial peptides kill or inhibit growth of closely related bacteria bacteriocins of Gram-positive bacteria are seldom active against Gram-negative bacteria

31 Commercially Available Products Bactoferm F-Lc pediocin Chr Hansen sakacin ALCMix1 plantaricin Danisco carnocin ALTA 2351 pediocin Quest Micocin carnocyclin Griffith Laboratories piscicolin carnobacteriocin oc

32 Selection of Cultures as Biopreservativesi Ability to produce antimicrobials in meats Limited sensory changes limited acid production weak protease activity limited gas production absence of slime production

33 Counts of L. monocytogenes in the presence of SL/SDA and/or Micocin on vacuum packaged wieners stored at 4ºC 8 Lo og CFU/c cm No antimicrobial SL/SDA Micocin Micocin + SL/SDA Time (Days)

34 Results of enrichment and selective plating on PALCAM agar for wieners e inoculated with L. monocytogenes Treatment Storage time (days) Half SL/SDA Full SL/SDA Micocin Micocin Half SL/SDA Micocin Full SL/SDA

35 Growth of Listeria monocytogenes on sliced turkey, ham or roast beef treated with Micocin and stored at 4 C Lo og CFU/c cm 2 10 Avg ggrowth of L. monocytogenes 8 without Micocin 6 Turkey + Micocin Storage time (days) Ham + Micocin Roast beef + Micocin

36 Change in the intensity of a sour flavor in vacuum packaged wieners inoculated with potential biopreservatives and stored at 4 C Intensity Score (cm) Frozen reference Control Leuc. gelidum UAL187 C. maltaromaticum LV17 C. maltaromaticum UAL Storage Time (weeks) McMullen et al, 2000

37 Biopreservation and impact on Micocin quality of RTE meats No impact on flavour attributes Spoilage = sourness, metallic, dairy, chemical Flavour = saltiness, sweetness, sourness, bitterness, smoke, meat, garlic and pepper flavours

38 Post-processing technologies Assist in control of L. monocytogenes Not a replacement for good manufacturing practices Multiple hurdle approach most effective Needs to be validated in products