Recontamination Issues in the Food Processing Industry What, Where, and How Important are They?

Recontamination Issues in the Food Processing Industry

What, Where, and How Important are They?

Dr. Paul A. Hall

PresidentAIV Microbiology & Food Safety Consultants, LLC

Hawthorn Woods, IL USA

Producing Safe Food is Our Top Priority!

• Consumer protection and trust

– Consumers must be able to trust the brands they buy and the food they eat

– Food safety is absolutely critical to that trust

• Business survival/self-interest

– Our brands are our most important asset

– History is replete with brands and businesses being destroyed because of a lapse in food safety

• Industry responsibility

– Moral obligation to produce food as safe as practical

– Industry pledge not to make safety a competitive issue

Why is Food Safety our Top Priority?

• It is a cost of doing business

• The changing global food safety landscape demands more diligence, flexibility, and speed than ever before.

• The cost impact of not doing food safety right is higher than it’s ever been.

• The benefits of doing food safety right contributes directly to the bottom line – and not just in cost avoidance.

• Consumer and regulatory scrutiny are at an all time high.

• World class companies that win in the marketplace have world class food safety principles.

Causes of Foodborne Contamination

• Food Products can become contaminated via several routes:

– Naturally occurring (raw foods)

– Underprocessing/improper processing

– Recontamination/cross-contamination

• Pathogens

• Spoilage organisms

• Allergens

• Chemical contaminants

– Intentional contamination

• Economic adulteration (e.g melamine)

• Bioterrorism

Recontamination Issues in the Food Processing Industry

• Food products that are subject to a lethality step are generally free of vegetative pathogens and depending on the degree of treatment, free of spore forming pathogens.

• However, post-lethality recontamination can occur if proper procedures/practices are not in place.

• Additionally, recontamination can occur at different points along the farm-to-fork continuum.

Importance of Recontamination in the Food Processing Industry

• Question: How important is the issue of recontamination to the food industry?

Answer: Extremely Important!!!

Factors Contributing to Pathogens in Foods

A WHO survey performed in Europe found cross-contamination to be the most important factor relating to the presence of pathogens in prepared foods:

Causative Factor Percentage of Cases

Cross contamination 28.9%

Improper storage 25.3%

Raw foods 18.4%

Infected persons 9.7%

Inadequate handling 9.2%

Contaminated ingredients 4.8%

Contaminated equipment 3.0%

Other 0.7%

Adapted from: Rocourt, J. et al. 2003. Present State of Foodborne Disease in OECD Countries. WHO, Geneva, Switzerland

A summary of principal known factors contributing to foodborne illness in Washington State (USA) from 1990-1999:

Causative Factor Percentage of Cases

Inadequate hand washing 31%

Inadequate holding temperature 24%

Inadequate refrigeration 20%

Slow cooking 20%

Cross contamination 18%

Bare hand contact with food 13%

Ill food worker 13%

Source: Washington State Dept. of Health. Foodborne Illness Outbreaks Update, 2002

Factors Contributing to Pathogens in Foods

Examples of Outbreaks Attributed to Recontamination Originating from Various Sources Across the Food Chain

Organism Product Processing Equipment

B. cereus Pasteurized milk Filling equipment

E. coli O157:H7 Different foods Slicing and handling utensils in supermarket

S. agona Breakfast cereal Probably filling and packaging machine

S. berta Soft cheese Buckets for cheese ripening previously used for raw eggs

S. enteriditis Ice cream Tanker used to transport ice cream previously used for raw eggs

S. enteriditis PT4 Pastry Mixing bowl, cream piping bags and nozzles not cleaned

S. typhimurium Cooked sliced ham Containers previously used for curing raw pork

E. coli O157:H7 Flavored yogurt Pump previously used for unpasteurized milk, insufficient zoning?




Organism Product Raw Materials

C. botulinum Cheese Contaminated onions added

Salmonella serovars Paprika potato chips Contaminated paprika powder

Y. enterocolitica Chocolate milk Probably contaminated chocolate syrup added to pasteurized milk



Organism Product Environment

C. parvum Water Secondary contamination of potable water

L. monocytogenes Butter Processing environment

L. monocytogenes Hot dogs Environment

Salmonella serovars Citrus products Amphibians entering the production facility?

S. ealing Infant formulae Environment of processing lines and equipment

S. typhimurium DT170 Kebab, yogurt relish Juice from carcasses dripping into open containers of yogurt

Y. enterocolitica O:8 Pasteurized mild Post-process contamination from the environment



Organism Product Handling at or Close to Point of Consumption

C. parvum Different foods Infected food handler

E. Coli O157:H7 (hamburger) No hand washing after handling raw beef

Norwalk-like virus Salad items Asymptomatic food handler who had taken care of sick child

Norwalk-like virus Ham, chicken dish Pre-symptomatic food handler who had taken care of sick child

S. sonnei Sandwiches Post-symptomatic food handler at conference

Y. enterocolitica Cooked pork intestines

Unknown; patients too young to consumer the product

Unknown

C. jejuni (O:33) Tuna salad Probably chicken handled in the same chicken

E. sakazakii Infant formula Unknown

S. enterica serovar Newport

Ham Ham served at funeral meals, source unknown

Case Studies

Salmonella in Sesame Seed

Products

Salmonella in Sesame Seed Products

• In 2001, recalls of a sesame seed product, halvah (a candy made of sesame seed, sugar and flavor) occurred in Australia and Sweden.

• The halvah was contaminated with multi-resistant Salmonella typhimurium DT104.

• One survey showed that Salmonella can be isolated from sesame seed products.

Food No. Samples Producer No. Salmonella serovars isolated

Sesame paste 12 8 1

Halvah 71 16 8

Sesame seed 16 6 2

Pastry 5 5 -

Sesame oil 7 4 -

Cereal 6 2 -

Total 117 25 11 (9.4%)

Source: Brockmann, S.O. et al. JFP 67(1):178-180. 2004

Initial screening/cleaning of dried seeds

Hulling (aqua-hulled or mechanically-hulled)

Sieved and wet-cleaned dehulled seeds heated to 120°C (Tahini production)

Milling (130°C) to produce tahini

Manually mix Tahini and acidified heated glucose syrup (≥80° Brix) at 140°C

Add flavor/other ingredients (e.g. pistachio)

Poured into jars

Sesame Seed Processing

• Sesame seed can be contaminated with Salmonella during growth of the plant, storage, or processing.

• However, Salmonella should not survive the production of halvah because of the high temperature (>120°C) employed in the process.

• The likely cause of the outbreaks was cross-contamination of the halvah during packaging and/or transport.

Salmonella in Sesame Seed Products

Salmonella in Peanut Butter

Peanut Butter Industry Facts

• Peanut butter is a ~1 billion $ industry in U.S.

• 5 major manufacturers account for 75% of production

• 50% of U.S. peanut crop used for peanut butter

• Peanut butter is found in 90% of homes in U.S.

• Average consumer eats peanut butter 27 times/year

• Peanut Butter is produced from roasted shelled peanuts

• Fat content ranges 49-52%

• Salt is usually added at a 1-2% final concentration (lower in dietetic formulations)

• Moisture content <1%, aw <0.3%

• Low aw precludes the active growth of spoilage organisms and pathogens

Peanut Butter Characteristics

Peanut Butter Manufacturing

Raw Shelled Nuts Roasted (Continuous or Batch 170º -180º C)

Blanched to Remove Skins

Ground and Milled(Salt/Dextrose/Stabilizers Added)

Homogenized (optional)

Packaged

• Raw peanuts, as with other raw agricultural commodities, are known to be contaminated with Salmonella spp

• Studies have shown that the most heat resistant strain (Salmonella seftenberg) is inactivated by peanut roasting

• Contamination of peanut butter with Salmonella spp. occurs via post-roasting recontamination

• Prevention of recontamination depends largely upon effective separation of raw peanuts (and associated dust/fines) and the post-roast processing areas

• Once peanut butter is contaminated with Salmonella spp., it will survive for prolonged periods of time

Salmonella in Peanut Butter

• First outbreak linked to peanut butter was reported in Australia in 1996 (Salmonella mbandaka)

• Salmonella agona outbreaks reported in 1996 in 4 countries was associated with the consumption of a peanut butter coated RTE savory snack

• First outbreak in the U.S. traced to Salmonella tennessee in peanut butter was reported in February 2007

History of Salmonella in Peanut Butter

• Inadequate separation of pre-roast/post-roast processing areas.

– Dust/fines present in the post-roast areas

• Roof leak and faulty sprinkler head leak introduces moisture into the environment allowing for potential growth of Salmonella tennessee

• During subsequent processing, handling, and filling, Salmonella tennesee found its way into the product

Factors Contributing to the 2007 Salmonella Recall

• Typical dry cleaning procedures were not able to eliminate the pathogen from the environment

• Environmental monitoring procedures were insufficient to detect the organism in the environment

• Finished product testing also did not detect the organism implying sporadic contamination

Factors Contributing to the 2007 Salmonella Recall

Listeria monocytogenes in Hot Dogs

Listeria monocytogenes Overview

• Listeria monocytogenes is a Gram positive, non-spore forming rod that can grow at refrigerated temperatures.

• L. monocytogenes is ubiquitous in the environment and can be isolated from a wide range of foods.

• Certain strains of L. monocytogenes can cause illness in humans:

– Neonates (sepsis, pneumonia, meningitis)

– Pregnant women (fever, miscarriage, stillbirth)

– Elderly (sepsis, meningitis, focal infections)

– Immunocompromised (sepsis, meningitis, focal infections)

– Healthy adults (rarely, diarrheal illness)

• High levels of L. monocytogenes have to be consumed in order to cause illness

• Certain foods pose an increased risk of being associated with listeriosis

• These foods have the following properties:

– Have the potential for contamination with L. monocytogenes

– Support the growth of Listeria to high numbers

– Are ready-to-eat foods

– Require refrigeration

– Stored for extended periods of time

Characteristics of High-Risk Foods

Foods can be classified according to their risk,

based on their properties and history of known illness

Listeria Risk Classification

Clusters A and B Clusters C and D Cluster E

Very High RiskDeli MeatsFrankfurters (not reheated)

High RiskPâté and Meat SpreadsUnpasteurized Fluid Milk Smoked Seafood

Moderate RiskNo food categories Cluster 1

High RiskHigh Fat and Other Dairy Products Pasteurized Fluid Milk Soft Unripened Cheese

Moderate RiskCooked RTE Crustaceans

Moderate RiskNo food categories

Cluster 2


Moderate RiskDeli-type Salads Dry/Semi-dry Fermented Sausages Frankfurters (reheated) Fresh Soft Cheese Fruits Semi-soft Cheese Soft Ripened Cheese Vegetables

Low RiskPreserved FishRaw Seafood

Cluster 3


Low RiskNo food categories

Very Low RiskCultured Milk Products Hard Cheese Ice Cream Frozen Dairy Products Processed Cheese

Cluster 4

Dec

reas

ed R

isk

per

Ser

vin

gDecreased Risk per Annum

Source: US FDA Listeria Risk Assessment, 2003

Typical Process Flow for Hot Dog Production

Source: ICMSF Microorganisms in Foods 7, 2002

Receiving Raw Materials Storing Grinding

Emulsifying ChoppingFormulating/

Blending

Stuffing into Casings Cooking

Cooked Product Area (Refrigerated)

ChillingPeeling to Remove Casings

Shipping PackagingCollating

Frankfurters

Raw Material

Area

• An estimated 20 billion hot dogs are consumed annually in the U.S.

• Hot dogs are cooked to a lethal temperature sufficient to destroy L. monocytogenes.

• Post-cooking recontamination of hot dogs can occur during subsequent handling prior to packaging.

• Furthermore, recontaminated hot dogs that do not contain inhibitors can support the growth of L. monocytogenes to high levels.

• Subsequent re-heating of the hot dog (e.g. microwaving) may be insufficient to reduce levels, leading to illness in susceptible individuals.

Listeria monocytogenes in Hot Dogs

• A combination approach has been used to eliminate/control L. monocytogenes in RTE meat products:

– Better hygienic design of equipment

– Reformulating product to inhibit growth

– Improved sanitation protocols

– Aggressive monitoring of equipment and processing environment for Listeria

– Training of personnel

Control of L. monocytogenes in Hot Dogs

• Listeria Control Equation is based on the premise that intensive environmental monitoring is effective in understanding the plant’s control measures.

• Systematic, disciplined approach to seek out, find and eliminate the undesirable conditions which could support harborage or transference of pathogens.

Listeria Control Equation

Listeria Control Equation

Mismanagement of any of the components may increase the risk of cross-contamination

Traffic patterns GMPs

Dry, uncracked, clean floors

Sanitary design

Sanitation procedures

Listeria Control+ +++ =

Zoning Concept – A Useful Tool for Monitoring the Production Environment

Zone 1

Product contact surfaces such as slicers, conveyors, peelers, strip tables, utensils, racks, work tables, employee hands

Zone 2

Exterior of equipment, chill units, framework, equipment housing

Zone 3

Phones, hand trucks, forklifts, walls, floor and drains

Zone 4

Locker rooms, cafeteria, halls, warehouse, loading dock

Comprehensive Environmental Monitoring Program

• Timely assessment of control of RTE environment

• Biased intensive sampling before and during production to monitor all areas

• Large surface areas sampled for Listeria genus or other suitable indicator

• Sampling is randomized (by the day of the week and shift)

• Every RTE processing line must be sampled, ideally on a weekly basis

• Sampling plans need to be flexible and tailored to each specific line and facility

Common Routes of Recontamination

Common Routes of Recontamination

• Raw materials

• Food contact surfaces and equipment

• Airborne contamination

• Pests

• Personnel

• Direct addition of contaminated raw materials/ingredients to previously processed product

– Salmonella in paprika used to season potato chips

– Y. enterocolitica in chocolate syrup use to prepare chocolate milk

– C. botulinum in onions added to cheese

– Salmonella-contaminated ingredient added to non-RTE microwavable pot pies

• Direct or indirect inadvertent commingling of raw materials and finished product

– Tuna salad contaminated with C. jejuni (O:33) during preparation

– Salmonella in pasteurized milk inadvertently commingled with raw milk

Common Routes of Recontamination: Raw Materials

• Usually occurs via water droplets from high pressure hoses, condensation from ceilings and overheads, dust, and occasionally exhaust vents

– Droplet transmission from drains in a fish processing facility (L. monocytogenes)

– Dust contamination of extruded dog food (Salmonella)

– Water droplets from leaky roofs (Salmonella in peanut butter)

– Inadvertent sewage water from leaky pipe over processing line (Salmonella in chocolate)

Common Routes of Recontamination: Airborne Contamination

• Insects, birds, amphibians, and rodents are recognized vectors for transmission of pathogens

– Salmonella outbreak in orange juice traced to amphibians coming into the processing facility

Common Routes of Recontamination: Pests

• Inadequately cleaned surfaces and equipment can be a major source of recontamination

– L. monocytogenes in hot dogs

– E. coli O157:H7 in flavored yogurt contaminated via pump

– RTE sandwiches in major retail chain due to cross-contamination during assembly at the store (Salmonella and L. monocytogenes)

– Listeria-contaminated slicer blade in RTE spiral ham operation

• Containers and packaging materials used to store or transport processed products have been sources of recontamination

– Salmonella in ice cream mix contaminated in tanker truck used for unpasteurized raw eggs

Common Routes of Recontamination: Food Contact Surfaces and Equipment

• Transfer of pathogens to foods via food handlers is a well-established mode of contamination

– Hepatitis A outbreak among school children traced to strawberries contaminated from infected field workers

– S. sonnei infection traced to spring onion contaminated by a food handler

– Norwalk-virus outbreaks in cruise ships traced to contaminated food handlers

• Deficient or absence of hand washing has been identified as the most frequent cause of low infectious dose pathogen transmission

Common Routes of Recontamination: Personnel

Avoiding Recontamination Issues – Putting it all Together

Putting it all Together

• The food industry must be committed to the highest possible standards of food safety throughout its operations and should take significant measures to that end:

– Each food company should have an established Senior Leadership position, to bring additional focus to developing and implementing programs that continuously improve product safety and design.

– Companies should consider the use of external expert food safety advisory bodies and process authorities to provide guidance on issues of food safety.

– Companies should have the proper checks and balances to ensure that their suppliers and co-manufacturers are in compliance with established food safety standards.

• HACCP and associated pre-requisite programs should be the cornerstone of a company’s food safety program:

– HACCP plans should be reassessed ideally on an annual basis or if there are any significant process changes.

– HACCP plans should be developed using experienced cross-functional teams and reviewed/approved by a third-party expert authority if in-house expertise is not available.

– Food Safety Assessments should be conducted to determine if the HACCP plan and pre-requisite programs are being followed and to identify gaps in the food safety system.

– Food companies should require that their suppliers and co-manufacturers have implemented a valid HACCP plan and associated pre-requisite programs.


• Food Companies must commit to making significant capital and resource investment to ensure the production of safe food:

– Installation of state-of-the art equipment and process redesign.

– Complete separation of raw ingredients from finished product areas.

– Implementation of an aggressive environmental monitoring program for pathogens or indicators of pathogens in the plant.

– Implementation of a validated allergen control plan.

– Implementation of statistical sampling plan for finished product testing on all lots of finished product (where it adds value).

– Use of the latest leading-edge detection technologies for all pathogen testing.


• Sponsorship of leading-edge research for control of pathogens in food products from farm to fork.

• Proactive leadership in external committees, trade organizations, and research institutions to promote food safety.

• Conduct in-depth safety and quality system and capabilities assessments using cross-functional teams and independent technical experts at targeted manufacturing plants.

• Assess overall recall and traceability processes across our supply chain.

• Assess organizational capabilities across Operations to ensure proper resource allocation.


Thank you!

A Presentation at the IAFP Latin America Symposium on Food Safety

Royal Palm Plaza Hotel resort

Campinas, SP, Brasil

May 26, 2008

[email protected]

Recontamination Issues in the Food Processing Industry What, Where, and How Important are They?

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