Challenges & Solutions for “Preservative-free,” Microbial-Safe Foods Kathleen Glass, Ph.D. Associate Director Food Research Institute University of Wisconsin-Madison [email protected]; 608.263.6935 Clean Label Conference, 26 March 2019 March 26-27, 2019
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Challenges & Solutions for “Preservative-free,”
Microbial-Safe Foods
Kathleen Glass, Ph.D.Associate Director
Food Research InstituteUniversity of [email protected]; 608.263.6935
Clean Label Conference, 26 March 2019
March 26-27, 2019
Overview• Challenges: Preservative-free foods may pose
food safety risks• Developing Solutions
– Factors to control microbial growth– “Clean label” alternatives to synthetic preservatives– Factors affecting efficacy of antimicrobials
• Summary
2
Making Processed Foods Safe: The Ideal
3
Validated Cooking or Alternative Lethality
Rapid Chilling
Controlled temperatures during distribution/storage
Cleaning & Sanitation
Making Processed Foods Safe: Facing the Reality
4
Large quantities thermodynamically
difficult to chillHeat resistant
microbes
Temperature abuse at retail and at consumer levels
Recontamination at retail or at consumer
levels
Niches in equipment and processing
facilities
Extended Runs
Microbes Cause Foodborne Illness• 48 Million episodes of foodborne illness per year• 128,000 hospitalizations• 3,000 deaths
– Salmonella (<1% mortality)– Listeria monocytogenes (~20% mortality, 90% hospitalizations)– Toxoplasma gondii (84% mortality in AIDS patients)
• Economic impact: US$ 7billion annually – Medical costs & lost wages– Litigation, recalls, lost business, business closures
• Contributing factors: Lack of kill step, cross-contamination, temperature abuse, and lack of microbial growth inhibitors
Scallon et al., 2011; University of Florida Emerging Pathogens Institute, 2011
Case Study: RTE Meats with no growth inhibitorsL. monocytogenes, storage at 41°F (5°C)
Learning Lessons the Hard WayListeriosis in Ready-to-Eat Meats
7
1998 2002 2008 2018
US Hot dogsDeli meats50 cases8 deaths
US Deli-style Turkey meat46 cases10 deaths
CanadaSliced meats57 cases22 deaths
South AfricaPolony1060 cases216 deaths
US 2004: lactate, diacetate2013: propionate, benzoate
Canada 2012: lactate, diacetate
Outside North America: Approval??
Approval of antimicrobials
*Waiver for use prior to these dates.
Antimicrobial research fast tracked
Lessons learned: need sanitation, temperature control, antimicrobials
If we use GMPs, why need preservatives?
• Supplement current good manufacturing practices• Control microorganisms throughout the food chain,
production to consumption• Ability of disease causing bacteria to grow at
refrigeration temperatures• Susceptible consumers• Recontamination of cooked products• Improper holding temperature
8
Ecosure 2007: Retail Temperatures
9
0
10
20
30
40
50
60
Cottage Cheese Yogurt PrepackagedLunch Meat
Deli CounterMeat
PrepackagedDeli
Fresh Meat
Percent of Product Observed above 41°F at Retail
> 50°F > 45°F > 41°F
2.6% of prepacked lunch meat >54°F1.9% of deli meat >54°F
Ecosure 2007: Home Refrigerator
10
Mean product temp (°F) 38.2°F
% above 41°F 17%% above 45°F 5%% above 50°F 0.7%
Maximum temperature 63°F
Solution: Adjust pH and water activity to inhibit microbial growth
11
Critical pH
Critical AW 4.6 or less 4.6 to 5.6 >5.6
0.92 or less Growth inhibition Growth inhibition Growth inhibition
>0.92-0.95 Growth inhibition Growth inhibition ??
>0.95 Growth inhibition ?? ??
?? = Use antimicrobials; starter/protective cultures, etc. to improve safetyAdditive or synergistic effect allows lower level of each factor to be usedRequires time/temperature control unless product testing demonstrates otherwise Adapted from: IFT. 2001. Evaluation and Definition of Potentially Hazardous Foods, IFT/FDA Contract No. 223-98-2333.Water activity impacted by moisture, protein and salts rather than other humectants
Protective culturesCompetitive microfloraIn situ acid/bacteriocin production
* Clean label substitute with documented efficacy
Effectiveness as an antimicrobial• Concentration of active compounds• Solubility of antimicrobial• Dissociation constant• Food composition
– pH/water activity/moisture/salt – Fat, hydrophobic proteins, free iron
• Synergistic/additive effects between antimicrobials• Processing, cooling and storage temperature/time
13
Effect of Organic Acid Type
PropionicpKa 4.87
AceticpKa 4.76
LacticpKa 3.86
Citric pKa 3.13, 4.76, 6.40
Journal of Applied Bacteriology 1996, 81, 147-1 53, Metabolic activities of Listeria monocytogenes in the presence of sodium propionate, acetate, lactate and citrate., Y. Kouassi and L.A. Shelef , Department of Nutrition and Food Science, Wayne State University, Detroit, MI, USA
Foodborne Pathogens and Disease 2012, 9, 1126-1129. Comparing Organic Acids and Salt Derivatives as Antimicrobials Against Selected Poultry-Borne Listeria monocytogenes Strains In Vitro. , J.F.R. Lues and M.M. Theron.
23456789
0 2 4 6 8
2
3
4
5
6
7
8
9
0 2 4 6 82
3
4
5
6
7
8
9
0 2 4 6 8
23456789
0 2 4 6 8
L. m
onoc
ytog
enes
(log
CFU
/g)
Citric Lactic
PropionicAcetic
Solution: Effect of acid type, pH, and moisture on L. monocytogenes in “preservative-free” fresh cheese
Engstrom et al., 2018, manuscript in preparation
Solution: Fermentates• Labeled as cultured milk, cultured sugar• Commercially available proprietary ingredients• Likely active compounds
– Organic acids; single or blends (lactic, propionic)– Frequently blended with vinegar (acetic)– May or may not contain bacteriocin activity
Challenge: removal of synthetic antimicrobials allow botulinum growth during mild temperature abuse Solution: Cultured celery and vinegar or CS-V blend
Glass et al., unpublished data, 2017
60 ppm ingoing nitrite + 250 ppm cure accelerator (erythorbate or cherry powder)60% moisture, pH 6.3, 2.2% salt
Challenges• Preservative-free foods may pose a health risk• Clean label “preservatives”
– Undefined activity between manufacturers; lots– Contain low concentrations of active compounds– Addition levels may negatively affect sensory attributes
• No single antimicrobial will control all microbes• Affected by processing, food components,
temperature control, intrinsic factors (aw, pH)• Must be validated in specific foods
– Formulations changes may be needed to optimize efficacy
31
Solutions• Clean label antimicrobials can be applied to wide
variety of foods• Ingredient companies are actively developing clean
label alternatives to synthetic preservatives• Optimization of ingredients can reduce usage levels,
improve sensory attributes and be cost-effective• Clean label growth inhibitors that are familiar to
consumer can inhibit microbial growth – Enhance the safety of foods– Enhance confidence by consumers