Advanced Processing
State-of-the-art optical sorting, hulling, pasteurization, and roasting — all under one certified California facility roof.
Premium Quality at
Every Sorting Stage
Our 100,000+ sq. ft. processing facility in Wasco, California uses Buhler optical sorters, high-speed laser grading lines, and continuous-belt roasting machinery to deliver nut products of unmatched consistency. We operate three independent processing bays designed to separate raw receiving, roasting/seasoning, and allergen-sensitive custom packing runs.
To guarantee microbiological purity without compromising flavor, our facility features the Safesteril steam-pasteurization chamber. This thermal treatment utilizes superheated dry steam under vacuum to eliminate pathogens (achieving an validated >5-log salmonella reduction) while preserving the raw kernel's delicate green color, crisp snap, and original oil profile.
We accommodate a wide variety of custom roasting parameters. Our engineers calibrate variables such as conveyor belt speed, airflow velocity, and temperature zones in our industrial roasters to yield the exact flavor profile and roasting depth required by our wholesale food brand partners, from light-dry roasts to deep-salted configurations.
From initial hulling through drying, sorting, roasting, and packaging — every stage is monitored by dedicated QC technicians under SQF Level 3 and FDA facility certification.
Industrial-Grade Machinery
Buhler Optical Sorters
High-definition camera arrays detect colour, surface defects, and foreign material at 10 tons/hour.
Safesteril Pasteurization
Steam-based natural pasteurization that kills pathogens while preserving full flavour and texture profile.
Continuous Belt Roasters
Even hot-air circulation at calibrated temperatures for uniform roasting across every batch.
Custom B2B Processing
Private-label roasting, seasoning, slicing, dicing, and custom vacuum-pack configurations.
The Processing Pipeline
Receiving & Hulling
Freshly harvested pistachios are weighed, received, and immediately run through mechanical hullers to remove the outer hull.
Forced-Air Drying
Hulled nuts pass through high-volume drying tunnels to achieve precise moisture content before storage or sorting.
Optical & Laser Sorting
Multiple passes through camera and laser sorters to remove defective nuts, shells, and foreign material.
Sizing & Grading
Nuts are sized through precision screens into multiple grade categories for different retail and industrial markets.
Roasting & Seasoning
Custom dry-roasting and flavouring programs applied under HACCP-controlled protocols.
Packing & Dispatch
Packaged into super sacks, vacuum bags, or custom retail formats and released under COA with full traceability.
Pasteurization Chemistry & Kill Step Validation
Since the implementation of the USDA Agricultural Marketing Service (AMS) mandatory pasteurization rule for California almonds in 2007 — and its subsequent application to other tree nuts — the pistachio industry has adopted pasteurization as an industry best practice even where it is not yet legally mandated. Primex Farms pasteurizes all retail-destined product and a significant portion of our wholesale-out product using the Safesteril process, a proprietary food-grade ethylene oxide and steam combination treatment validated to achieve a minimum 5-log10 reduction in Salmonella Enteritidis — the most heat-resistant relevant pathogen in nut food safety.
The thermodynamic basis of pasteurization is the D-value concept: the time required at a specific temperature to reduce the target organism population by 90% (one log10 reduction). For Salmonella on pistachios, the D-value at 170°F (77°C) in product moisture conditions relevant to in-shell pistachios is approximately 0.8–1.2 minutes, meaning that a 5-log10 reduction requires approximately 4–6 minutes of exposure at this temperature throughout the mass of the product. The engineering challenge is ensuring that the coldest point within the densest product mass reaches and holds this temperature for the required time, because nuts in the center of a bulk bin or at the core of a product stream may lag significantly behind the surface temperature. Our validated pasteurization protocol uses pre-conditioning holding rooms to bring product to a minimum starting temperature before treatment, reducing the thermal gradient between surface and core and shortening the required process time.
For natural (un-roasted) in-shell pistachios, steam pasteurization is the preferred method because it achieves the required kill step without significantly altering the shell appearance or kernel flavor that characterizes natural product. The Safesteril chamber uses superheated steam injection combined with controlled pressure cycles to drive steam penetration into the product mass, followed by a rapid vacuum drying stage that removes the moisture added during steaming — restoring the product to its pre-treatment moisture specification without additional oven drying that would change shell color or kernel texture. Temperature and humidity within the chamber are monitored by calibrated data loggers at eight locations within the product mass, and process records from every batch are retained for five years as part of our FDA FSMA preventive controls documentation.
For roasted pistachios, the roasting process itself serves as a validated kill step when conducted at parameters that deliver sufficient thermal energy throughout the product. Our dual-belt continuous oven roasting process achieves a minimum product core temperature of 285°F (141°C) for a minimum of two minutes on all standard roasting profiles — parameters that vastly exceed the thermal requirements for Salmonellaelimination and simultaneously achieve the Maillard browning reactions and moisture reduction that create roasted pistachios' characteristic deep, nutty flavor. The oven is equipped with multiple temperature zones — a pre-heating zone, main roasting zone, and finishing zone — each with independent thermocouple-controlled gas burners and a forced-circulation hot-air system that maintains temperature uniformity across the full belt width to within ±5°F.
Roasting chemistry is a fascinating area of food science that directly impacts the flavor profile of our finished product. During roasting, three major chemical transformations occur simultaneously in pistachio kernels. The Maillard reaction — a cascade of non-enzymatic browning reactions between reducing sugars and free amino acids — generates hundreds of volatile aromatic compounds including pyrazines (responsible for the toasty, nutty aroma), furans, and aldehydes. Simultaneously, some of the kernel's naturally occurring green chlorophyll is degraded by heat to pheophytins and pyropheophytins, shifting kernel color from bright green toward olive or yellow-green. And the kernel's lipid fraction undergoes controlled oxidation at the surface, generating short-chain aldehydes and ketones that contribute to the characteristic 'roasty' note preferred by most retail consumers. Our roasting calibration targets a shell surface Hunter L* color value of 68–74 (off-white with a slight golden tone) and a kernel surface L* of 55–62 (toasted cream) — parameters calibrated against our buyers' specification sheets and validated with colorimeter measurements on every production run.
B2B Grading Standards & Flavor Customization
Primex Farms uses a tiered grading system for our commercial B2B product, built on USDA pistachio grade standards but supplemented by additional quality parameters that our experience shows are important to industrial buyers, confectionery manufacturers, and premium retail packagers. Our Primex Grade A (PGA) specification is our top grade: minimum 90% split rate, maximum 0.2% reject nuts (mold-visible, insect-damaged, shriveled), maximum 0.1% foreign material, moisture 9.0–10.0% in-shell, aflatoxin <2 ppb by ELISA. Our Primex Grade B (PGB) specification reflects USDA Grade A: minimum 85% split, maximum 0.5% reject nuts, maximum 0.1% foreign material, moisture 9.0–10.5%, aflatoxin <5 ppb. Both grades are certified on the lot-level Certificate of Analysis provided with every shipment.
Size grading for B2B kernel product is expressed in count-per-ounce categories: Large (<18 ct/oz), Medium (18–22 ct/oz), and Small (>22 ct/oz). Food manufacturers — particularly confectionery and ice cream producers — often prefer Large grade for finished product aesthetics, while Medium grade is widely used in baked goods, trail mixes, and snack bars where size consistency matters but premium sizing is less critical. Small grade kernels find application in pistachio paste, pistachio oil, and fine-ground pistachio flour production. Primex Farms can sort finished kernel lots to any of these size specifications or to a buyer-specified custom count range, with sorting throughput of approximately 3,000 lbs per hour on our kernel sizing equipment.
For food-service and private-label retail clients who require seasoned products, Primex Farms' seasoning capabilities cover dry-blend seasoning application via tumble drum, wet brine application via immersion tank and drain conveyor, and oil-glaze application via spray coating tunnel. Each seasoning method produces a different flavor adherence profile: dry blending produces a lighter, more evenly distributed coating suitable for standalone snacking; brine application penetrates the shell to season both shell surface and kernel interior, preferred by many Middle Eastern-style pistachio products; oil-glaze application provides a high-shine, premium appearance preferred for gift-box and specialty retail applications. Seasoning blends are customized to each client's flavor specification and manufactured using approved, allergen-documented ingredients from our approved supplier program.
Packaging formats available for B2B clients at Primex Farms span the full range of commercial needs, from bulk through retail-ready. Bulk options include 900 kg wooden bins with polyethylene liner (the standard harvest bin, reused for finished goods), 1,000 kg woven FIBC (bulk bag) with polyethylene inner liner, and 44-lb multi-wall paper bags with polyethylene inner ply. For retail and food-service, we offer 12-oz, 16-oz, 24-oz, and 48-oz heat-sealed barrier foil laminate bags printed in up to 8 colors using UV-resistant inks, and 5-lb and 10-lb vacuum-sealed bags for food-service distribution. All retail packaging formats include a one-way valve that allows CO2 off-gassing from recently roasted product without permitting oxygen ingress — critical for maintaining fresh roasted flavor over the 12–18 month shelf life claimed on the label.
Modified atmosphere packaging (MAP) is available as a premium option for clients requiring the longest possible shelf life on kernel products. In MAP packaging, the headspace gas in sealed bags is replaced with a nitrogen/CO2 mixture (typically 97% N₂/3% CO₂) that displaces residual oxygen to below 0.5% — levels at which oxidative rancidity development is suppressed to the point that kernel product can maintain its 'fresh' flavor characteristics for 24 months when stored at ambient temperatures below 75°F. Our MAP packaging line uses continuous-web form-fill-seal equipment with inline oxygen analyzer verification of every package before it is sealed and discharged, ensuring that no package with above-specification oxygen level leaves the facility.
For clients interested in establishing long-term supply agreements, Primex Farms offers annual forward pricing contracts that provide price certainty for 12-month periods, adjusted by a formula that references the Dried Fruit Association of California's annual pistachio price survey plus a fixed premium for Primex Farms' quality specification. These agreements benefit both parties: clients gain budget predictability and first-priority access to Primex Farms' crop, while we gain advance demand signals that allow more precise orchard and processing investment planning. Long-term clients typically receive enhanced documentation services including dedicated account management, quarterly quality reports, and priority scheduling for co-packing and custom processing runs.