How You can Use Statistics in the Food Industry - Part 3

Recap:
So far we have looked at Paredo, Histograms, Run charts, and Fishbone diagrams.  What next?  Process Capability, Gauge R&R, 6Sigma, and SPC.  Is there more than this - yes, but I think, once the above list is complete - further info would need to be part of a statistics course or a "6 Sigma (green or black belt) program".

Process Capability:

To begin a project of statistical process control, you need to start with a couple of tasks.  The first task is to construct a histogram of your test results to see if you have a normal curve and if your process falls within your upper and lower specification limits - is your process in control (this can be done visually - see part 1 of this series, or by doing a chi squared test)?  The second task is to do a process capability which can only be done if your process is in control. 

In process capability, there are two steps - The Cp and the Cpk.  Cp is a simple index that relates your processes spread to the upper and lower specification limits. 

1. If Cp is >1 you are in good control (the specification limits are wider than your variation)
2. If Cp=1 your specification limits are the same as your variation and 0.3% defect are being made. 
3. If Cp is > 1 your product variation is greater than your spec limits and you are making a lot of scrap. 

The calculation for this number is the upper spec limit minus the lower spec  limit.  The result is then divided by 6 multiplied by the "estimated process standard deviation" 

USL-LSL

6*STDDEV


The deviation is calculated by Range (or average of the ranges for all subgroups) divided by a factor called d2.  Where d2 comes from is a chart of factors for computing Central lines for X and R charts.  I have found a link (below) for this chart of factors.

http://www.dfx.nl/userfiles/file/pdf/Control%20Chart%20Constants%20and%20Formulas.pdf
 

The second task is the Cpk which not only takes into account the variation (spread) of the process but also asks "is the process centered?".  In other words is the mean of the histogram dead centre between the specification limits or is it closer to the upper or lower limit. 

1. If you are below 1, you are not centered and your processes variation is falling outside of the upper or lower specification limit. Thus producing out of spec product, as shown below:
   
2. At 1 to 1.33 you are OK but with no margin for error or drift (running the process too tight).  The process variation is right against either the upper or lower spec limit.
   
3. Above 1.33 - the higher the number the more room you have between your variation and the nearest specification limit.  You may wish to tighten-up your control limits in this case.

Once you have your data points, calculate the average (mean) and the standard deviation.  Subtract the mean from the upper spec limit and divide by 3 X standard deviation.  Do this calculation for the lower spec limit by subtracting the lower spec limit from the mean and then dividing by 3 X standard deviation.  The smaller of the two numbers will be your Cpk (also the spec limit your process is closest to). Equations;

USL-AVE

3*STDDEV

 And

AVE-LSL

3*STDDEV

 Free software at qualityadvisor.com is available as a quick and easy method of getting at this metric.  You will need to know how to select the subgroup size.  1 subgroup is one set of data from one lot and one production run.  Two subgroups would be data from two operators, two lots, etc.

For more information on the calculations, please take a look at isixsigma.com

 

Internal Audits - Part 2 of 2

In part one; I talked about what needs to be audited and about a few of the basics around auditing.  In part two, I will talk about some of the specific areas to look at during auditing and what makes a good auditor.

What makes a good Auditor?

In short, an auditor needs to be observant and have integrity.  Being observant means to be equipped with the proper tools such as a flashlight, mirror, knee pads, or any other tool that may be needed.  Personally; I like to think like an auditor.  If I think an auditor would use a ladder to look at refrigeration coils - I would use a ladder to inspect these coils myself.  A good rule is to think like an auditor before an auditor arrives.  Persistence and ability to deal with conflict are other traits that will be needed.  Let's face it, internal auditors will need to observe and measure what their friends and coworkers are doing - this will definitely setup conflicts.  No-one likes being watched and graded!

Lastly the auditor needs to be familiar with the general operation of the facility and be knowledgeable on the principles involved with the system / program / or element that is being audited.  Yes, auditors needed to be trained and the training needs to be refreshed every year as per SQF ????? and BRC section????.  SQF section 2.5.7.2 states that it would be ideal to have the auditors performing the checks on an area that is not part of their normal responsibilities or job duties.

Audit List Considerations

In general, HACCP, pre-requisite programs, and other regulations (organic, Kosher, etc.) need to be considered.

· CCPs (Critical Control Points) and QCPs (Quality Control Points) consider;

• Are the process flow Diagrams correct?
• Monitoring methods and frequencies adhered to
• Records being kept and legible (no pencil or white out) - signed, dated, completed
• Calibrations and records being completed - on schedule
• Review any recent corrective actions and are they completed

· Personnel

• Hygiene and cleanliness of the staff
• Rules on clothing are being adhered to
• Protective clothing and hair restraints being worn
• Signage is visible and appropriate
• Common areas are clean - including the inside of lunch fridges and microwaves
• Personal items are not worn - jewelry, cell phones, etc.

             · Visitors

• Signed in and wearing badges
• Have read and signed the policies and procedures that are required

· Chemicals and Storage

• Storage secured and lockable - is the lock being used
• Staff is trained
• Signage and handling instructions available
• W.H.I.M.I.S. and M.S.D.S up-to-date
• Transfer vessel cleanliness and condition
• Usage and inventory logs up-to-date
• Chemicals properly / legibly labelled
• Food grade chemicals and lubricants separated from non-food grade
• Hand/foot dips and hand sanitizers being used, monitored and maintained

· Toilets and Hand washing areas

• Clean and sanitary
• Warm water and soap available
• Paper towels and trash can available

· Cleaning and Sanitation Program

• Master sanitation schedule maintained, current, and followed
• Procedures available and being followed
• Cleaning material and equipment clean and properly stored
• Correct clothing being worn
• All materials are appropriate for the job
• Verifications being completed and recorded

· Pest Control

• Technician has a current liscence
• Maps are current
• Traps are clean, numbered, functional, and in their proper places.
• Service records and corrective actions are completed
• M.S.D.S sheets and technician licence up-to-date
• Bird control documented

· Other Areas for auditing

• Production area
• Storage area
• Shipping and receiving
• Maintenance workshop
• Exterior surroundings
• Record security
• Allergen program
• Foreign material
• Food Defence and Security

I am sure that this is not an exhaustive list and I could continue for a lot longer.  However, I think you get what is needed.  As a last note - make sure that all audits are recorded in writing and all corrective actions are completed on time.

Food Defence and Business Continuity

I have blogged about SQF once before and I wish to expand on the topics that are incorporated into this and the other Global Food Safety Initiative (GFSI) programs.  In GFSI programs, food defence and business continuity are issues that must be addressed; taking into consideration intentional threats and unintentional threats to product safety and will culminate in your company's recall procedure.  For SQF, the area to look at is in Module 2, Section 2.1.6.1 and 2.7.1; in BRC, 3.11.1.  Personally, I prefer the BRC code since it is all in one section.

Who would cause an intentional threat?  The people that we can clearly think of are criminals, terrorists, subversives and extortionists. The not so "usual suspects" can include competitors, disgruntled employees, and people not in their right mind.  This is the reason behind the FDA Bio Terrorism Act http://www.fda.gov/regulatoryinformation/legislation/ucm148797.htm

Since the source of a threat is unpredictable, the companies preparations to deal with a possible situation is what becomes important.  Do you keep the doors closed, do you have fencing, do you do security checks, or are areas in the facility (especially where product is exposed) monitored / observable.  Regular inventory counts can also be important to stopping intentional threats -- by noticing inventory disappearing or extra inventory appearing.  One of the best methods of protection/prevention is to answer the question:  will your employees report an unusual occurrence?

What about unintentional threats?  The most common unintentional threats (whether man-made or natural) are fire, flood, drought, hurricanes, tsunamis, mechanical failures, explosions, airplane crash, building collapse, and mislabelled product.  However unlikely the occurrence, if a company deems the threat to be probable, then the company needs to develop a plan of action for dealing with the occurrence.  It is odd to think of a plane crash as a threat to your business, but with so many industrial sites near airports, this does need to be considered.

For a plan of action, the following will need to be considered: 

1. A crisis management team needs to be selected and trained.
2. Controls need to be established to find and quarantine any compromised product.
3. Development and maintenance of a current emergency contact list.
4. The action plan must be written and not only to deal with the recovery of unsafe product, but also must address what needs to be repaired and develop estimates on how long before there is a return to normal business. 
5. A plan for communication (both internal and external- PR) will need to be developed - company spokesperson? You may need to include human resources management and lawyers in this plan.

Regardless of the crisis - companies need to be prepared. 

Pilot Food Facility at Conestoga College

Well - I wanted this blog to be about the Canadian Food Industry and to this end I toured an educational facility that is specifically focused on food processing.   The institute is called the Craig Richardson Institute of Food Processing Technology and it's chair is Luis Garcia.  This Institute is in Cambridge Ontario and is part of Conestoga college (a Polytechnic school which is the fastest growing college in Ontario with 60,000 students in total).

The facility is new as of September 2011 and is subsidized by the Canadian Government.  The need for the facility is based on the current lack of skilled labour in the Canadian the industry.  The Canadian food processing industry is number 1 in terms of labour force size and second in terms of revenue (second only to the auto industry).  Together these two pieces of information tell a story of future issues for companies getting enough skilled labour.  The institute wishes to address this labour gap by training students to be "skilled" operators and to also address the issue of poorly prepared supervisors (labourers lacking knowledge that become supervisors lacking knowledge). 

The program includes cleaning and sanitation, food safety, Microbiology, Chemistry, Mechanical and Electrical (specifically on issues that can arise in production).  Students can attend full time, part-time, or as an apprentice program.  The training facility includes three fully functional production lines and a Micro / chem laboratory.
Wow - a lot of hands on knowledge and experience can be gained at this facility.  They can even include tailored training for corporations that wish to better their employees.

The first line shown to us was for baked goods - from batching the raw dough to forming, tempering and baking.  The machines, as with all the machines in the facility, are standard equipment found in Canadian companies and are a combination of new technology with the ability to go manual (simulate older methods of processing).  The picture to the right shows a bread kneading and forming unit.





 
 The picture on the left shows the baking oven where students can learn how to operate the oven, and what can go wrong.  This teaching style is done for each line, step, process, and piece of equipment that the facility operates.

 The left picture shows a cooling tower for baked goods and a packaging line.

 

 The second line shown during the tour consisted of a beverage packaging setup that included batching, sterilization, filling, packaging, and cartoning. 

 The picture (right) is of the sanitation equipment for "Clean In Place" procedures.  Each line in the plant needs to be sanitized and this is all up to the students to perform;  including the testing for validation of cleanliness.  As part of the training, GMP is considered, taught and maintained in the facility.  Hand washing, hairnets, shoe baths, etc.

This facility is well organized and a place that I hope Canadian companies support and learn from.  I would love to get my hands dirty on these lines and increase my own knowledge.

How you can use Statistics in the Food Industry - Part 2

Paredo Chart: 

A Paredo Chart is a very simple method of Data analysis that, at its heart which says that is the 80 / 20 rule.  80% of the problems are from 20% of the causes.  Paredo charts can be used in charting events like customer complaints, where there are several types of issues.  The best way to proceed is to first collect the complaints and then organize them from most to least frequent.  Excel can do this task from a complaint list which is summarized in pivot table.  This pivot table can be charted and you can also add a line that tallies the frequency of each complaint.  When you reach 80% of the complaints, you focus on the issues that make-up that amount.

 The above is a quick example of jelly donut issues at a retail store.  The left axis is the number of complaints and the right axis is the cumulative frequency of complaints.  Ordered in this way, it is easy to see "filling squirting out"  is the largest complaint but is this the only complaint to focus on?  The cumulative frequency reaches 80% at "donut crumbled".  So, to correct 80% of the problems we need to solve both the jelly squirting and donut crumbling issues.

As you solve issues, this chart will change and different items will be included in the 80%.  This is a simple, quick, easy, and good way to keep a company focused on which corrective actions to spend time and resources on.


Run Charts:

A run chart plots process data to look for trends and analyze how the long range average is changing.  Below, I created a quick run chart to illustrate this simple method (The Variation of the Weight of Jelly Donuts). The average (mean) calculation for this plot can be found in Excel on the top bar under the formula tab.

The green line represents the mean which is calculated from the weights by the program. You will normally see data points both above and below the mean. As an example: a trend to look for is day 4-6 where the data is steadily rising. If this trend is left to continue it will lead to the weights being "out of spec".

How is this used during production? A blank chart with upper and lower specification limits is used at the start of the production run and the weights are plotted as the QC Tech or Operator weighs each sample. This is not to be confused with the Upper and lower control limits (see histograms in part 1).  The upper and lower specification limits are what you (the company) determine as the limit of acceptable product (based on info such as design of the machine and customer complaints).  With training, the production personnel can learn to look for trends and know when a product is "out of spec". Personally, I look for trends, for example, when three data points are above/below the mean and are approaching the spec limits. This method will give time for the personnel to correct the process before the product goes out of spec. Historical data gathered in this way can be used to help determine when an issue has occurred and how it will be dealt with. For example - a customer complains that the jelly donut dripped on their shirt. If this donut was made on day 15 - then we could say that a 15 gram donut has too much filling.

Verification Vs. Validation

I have found that these above terms are very easy to get confused.  They do look similar and can mean similar things. From www.thefreedictionary.com they are defined as:

verification [ˌvɛrɪfɪˈkeɪʃən]

n

1. establishment of the correctness of a theory, fact, etc.

2. evidence that provides proof of an assertion, theory, etc.

 

val·i·date (vl-dt)

tr.v. val·i·dat·ed, val·i·dat·ing, val·i·dates

1. To declare or make legally valid.

2. To mark with an indication of official sanction.

3. To establish the soundness of

 

In simple terms - verification are the tests on the product.  It is the daily/hourly/consistent "on the floor" testing that is documented, reviewed, and used to ensure the product is OK to ship.  Validation is a check on the system that is being used to test your products. The time period on validation can be yearly, monthly, quarterly, whichever time period has been designated as appropriate for the what you are auditing.

 In terms of Quality - Verification is the Quality Control and Validation is the Quality Assurance (for more on QA vs. QC see my blog posted March 21, 2012).  To verify - you are checking temperatures, hold times, pH levels - essentially recording the "proof" that your product is OK.  To validate - you are checking personnel training, the machines, the process steps - are the procedures being done as written.  Both of these duties / procedures need to be done and kept straight when you are in a GFSI program.

 

Quick example:   To verify a donut coming out of an oven you would test exit temps, or look at the number of off spec end temps for a month.   To validate the process you would check for oven cold spots, training logs, or even customer complaint logs.