Page 187 - Small Animal Clinical Nutrition 5th Edition

Commercial Pet Foods 189

trol points can be established around unit operations and qual- nonconforming product is identified and removed. This fre-
VetBooks.ir ity systems set up to monitor and ensure conformance. The quency depends on batch sizes, length of storage and normal
ingredient variation history. Sampling every 30 minutes for
manufacturing process of pet foods primarily involves proper
moisture, protein, fat, calcium, phosphorus, sodium, potassium
compounding of raw ingredients and then working this mixture
for moist or dry extruded products.Therefore, quality programs and magnesium to determine variation in the process is a good
must include: 1) calibration procedures for conveying the indi- starting point. Samples can be analyzed either separately or as
vidual ingredients, 2) proper time and temperature measuring a composite sample collected over time if the manufacturing
and 3) calibration procedures for the cooking process. For moist process is well controlled.
products, the sterilization program must be documented and For dry pet foods, sampling should include: 1) each lot of raw
recorded. Detailed records should be kept for each lot of prod- ingredients received, 2) the mix of raw ingredients once com-
uct manufactured, clearly detailing the processing conditions. pounded (weighed and mixed), 3) the product leaving the
Routine, clearly documented calibration and correlation pro- extruder, 4) the product leaving the dryer, 5) after any topical
grams must be established for each process variable (i.e., weigh- enrobing and 6) finished product in the package. For moist pet
ing or scaling, temperatures, flow rates, etc.). Analytical and foods, samples should be taken from: 1) raw materials, 2) prod-
physical testing of finished product is another essential element uct in the cooker/mixer and 3) sterilized product.
of a good quality program.
Statistical Process Control
Vendors To ensure the most consistent quality of the finished product,
Pet foods contain numerous raw materials from many suppli- modern factories use statistical process control in the manufac-
ers. A vendor quality control program is critical to ensuring turing process. Statistical process control determines normal
receipt of high-quality raw ingredients. variation through chemical analysis of the product at various
A good quality vendor control program begins with: 1) test- points in the process compared with nutrient specifications of
ing methods for nutrient levels, 2) microbiologic evaluation and the finished product. It also establishes control limits based on
3) toxicity testing. Defining these test methods ensures that this variation.
multiple vendors of raw ingredients deliver against the same Variables analyzed can be moisture, protein, fat or any other
purchasing specification. A routine calibration and correlation nutrient of concern for a particular product where consistency
program should be established to minimize method and oper- is required. Usually, two to three standard deviations from the
ator variations. A vendor quality program should establish the mean represent the control limits. Adjustments to the manu-
frequency of analytical testing; however, each lot of an ingredi- facturing process are made only when finished product attrib-
ent must be tested initially for moisture, protein and fat, at a utes are outside these control limits.
minimum, to see if it adheres to ingredient specifications and
for accurate compounding. Ingredients should also be routine- Analytical Tests
ly analyzed for other nutrients of concern (e.g., calcium, phos- Finished products are analyzed to ensure conformity to formu-
phorus, magnesium and sodium). lated nutrient content and freedom from toxins and microbio-
Beyond the testing required in a purchasing specification, logic concerns. At a minimum, a good quality program should
further quality assurance can be attained through programs the include routine testing to determine percentages of moisture,
food industry calls vendor self-certification. The objective of protein, fat, ash, calcium, phosphorus, sodium, magnesium,
these programs is to shift the focus from final ingredient ship- potassium and crude fiber. Additionally, incoming raw ingredi-
ment testing to building of quality control procedures upstream ents and finished products should be tested for Salmonella and
in the vendors’ process. For example, purchasing specifications Clostridium species, aflatoxin and vomitoxin.
for cereal grains would include a target value for percent mois- Each manufacturing facility should have an in-house labora-
ture of the grain. Most certification programs require vendors tory that can run the above analyses as the product is produced.
to keep detailed records on the lots of material they purchase. The results help operators adjust the process controls to ensure
The intent is to encourage vendors to define, understand and the finished product meets specifications. Faster analytical
control their raw materials and processes so that they manufac- methods (e.g., near infrared) that can analyze several nutrients
ture and supply ingredients that will fall within the pet food simultaneously with speed and accuracy help operators control
manufacturer’s specifications. the process. In addition to chemical analysis, the physical size,
density and color should be part of the finished product speci-
Product Quality fications. In the case of canned pet foods, can seal, product tex-
The quality of the finished pet food product is quantified by ture and vacuum should be recorded in addition to chemical
how well the product meets the formulated nutrient content analysis results.
as well as other critical parameters, such as: 1) consistent
appearance, 2) physical integrity, 3) package integrity, 4) ade- Shelf Life
quacy of sterilization and 5) freedom from toxins and micro- Shelf life is the amount of time a product maintains nutrition-
biologic concerns. al, microbial, physical and organoleptic (sensory) integrity. The
Sampling frequency should be established to ensure that any main cause of diminished shelf life in dry products is oxidation.