What Makes a Food Shelf-Stable?
A shelf-stable food is one that can be safely stored at room temperature without refrigeration — because its composition prevents harmful bacteria from growing. Two scientific properties determine this: water activity (aw) and pH. Guam's Division of Environmental Health (DEH) applies the same FDA and Guam Food Code thresholds used by commercial food establishments.
Understanding these two numbers is the most important technical skill a home food seller in Guam can have. If your product falls below both thresholds, it qualifies as shelf-stable and is the safest category to start selling from a licensed home kitchen. If it doesn't, it becomes a Temperature Control for Safety (TCS) food with additional handling requirements.
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Water Activity (aw)
≤ 0.85
Water activity measures how much free water is available for bacteria to use. A reading of 0.85 or below means most pathogens cannot survive or grow.
Low water activity examples
Cookies, crackers, honey, dried fruit, hard candy, dry spice blends, granola
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pH (Acidity)
≤ 4.6
pH measures acidity. Foods with pH at or below 4.6 are too acidic for most dangerous bacteria — including Clostridium botulinum — to survive.
High-acid examples
Jams, jellies, vinegars, properly acidified hot sauces, citrus-based preserves, fruit butters
A product can qualify as shelf-stable by meeting either the water activity threshold or the pH threshold — or both. Cookies are low in water activity. Strawberry jam is both low in water activity (high sugar) and high in acid. This dual protection is why traditional preserves have been safely stored at room temperature for centuries.
If you are uncertain whether your product is shelf-stable, testing by an accredited food lab is the safest approach before selling. Contact DPHSS/DEH at dphss-deh@dphss.guam.gov for guidance on local resources. [VERIFY lab testing options available in Guam]
Shelf-Stable Product Categories
What Qualifies Under the Home Industry License
These are the most common shelf-stable food categories that Guam home food sellers produce. All require the Home Industry license and DPHSS Sanitary Permit — but no additional commercial facility beyond your inspected home kitchen.
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Baked Goods — Shelf-Stable
Cookies (including guyuria, rosketti), dry cakes, breads, muffins, scones, biscotti, crackers, and brownies that do not require refrigeration. Must be fully baked — no unbaked dough sold for consumption. Cream cheese frosting, custard, or whipped cream filling turns a baked good into a TCS food requiring refrigeration.
Open
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Jams, Jellies & Fruit Preserves
High-sugar, high-acid fruit preserves are among the safest home-produced foods. Standard USDA-tested recipes using verified sugar and pectin ratios reliably achieve pH ≤ 4.6. Avoid low-sugar "diet" jam formulas unless you have pH-tested results — they may not be acidic enough without verification.
Open
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Hot Sauce & Acidified Sauces
Shelf-stable hot sauces must achieve and maintain pH ≤ 4.6 throughout the product. pH testing with a calibrated meter is strongly recommended — and may be required by DEH. Sauces that are not reliably acidified must be treated as TCS products and kept refrigerated. FDA may also require a process filing for acidified food products. [VERIFY with DEH]
Restricted
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Honey & Infused Honey
Raw honey has water activity of approximately 0.5–0.6 — well below the 0.85 threshold. Naturally shelf-stable with no additional acidification needed. Infused honeys (herbs, spices, citrus zest) remain shelf-stable as long as no fresh, moisture-releasing ingredients are suspended in the honey long-term. Dry infusions are safest.
Open
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Dry Spice Blends & Seasonings
Completely dry herb blends, spice rubs, seasoning salts, finishing salts, and single-origin spices. No moisture, no fresh herbs, no oil — dry only. Moisture content must be low enough that clumping does not occur in storage. Desiccant packets are recommended for humid climates like Guam's.
Open
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Granola, Trail Mix & Dry Snacks
Shelf-stable granola (baked, no dairy coating), trail mix with dried fruit and nuts, popcorn, dry crackers, and similar snack mixes. Any fresh fruit, yogurt coating, or cream-based topping makes the product TCS. Guam's humidity means moisture-proof packaging is important — resealable bags or sealed jars recommended.
Open
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Candy & Confections
Hard candy, lollipops, fudge, caramels, brittles, marshmallows, and nut bark are typically shelf-stable. Chocolates without dairy-based fillings (ganache, cream centers) are shelf-stable. Chocolate with cream or custard fillings is TCS — requires refrigeration and cold-chain awareness at point of sale.
Open
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Pickles & Pickled Vegetables
Vinegar-based pickles can achieve pH ≤ 4.6 and are shelf-stable. pH must be confirmed — refrigerator pickles (low vinegar, quick-pickle style) are not shelf-stable and must be labeled and handled as TCS. Fermented (lacto-fermented) pickles and kimchi are more complex — pH varies throughout fermentation and DEH verification is required before selling. [VERIFY]
Restricted
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Dry Baking Mixes & Pantry Mixes
Pancake mix, cookie mix, soup mix, seasoning packets, pasta blend kits — dry ingredients only. No wet sauce packets or pre-mixed wet ingredients. Must be fully shelf-stable at point of sale with no refrigeration needed before preparation.
Open
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Vinegars & Infused Vinegars
Naturally high-acid (pH typically 2.0–3.5), vinegars are among the most shelf-stable food products. Herb-infused vinegars, shrub bases (drinking vinegars), and specialty vinegars are all safely shelf-stable. Garlic-infused oil — not vinegar — carries botulism risk and must be properly acidified; see infused oils in the Restricted column.
Open
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Guam's tropical humidity matters. With average relative humidity above 75% year-round, shelf-stable products on Guam can absorb moisture more quickly than in drier climates. Use moisture-resistant packaging (sealed glass jars, airtight bags with oxygen absorbers) and include clear "store in a cool, dry place" instructions on your labels. Products with hygroscopic ingredients (sugar, salt, powders) are especially sensitive. When in doubt, test your packaging under local storage conditions before committing to a production run.
Sales Channels
Where You Can Sell in Guam
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Direct from Home
Allowed
With a Home Industry license and DPHSS Sanitary Permit, you may sell directly to customers who come to your home. Only immediate family may assist.
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Online Sales
Allowed
Online sales and delivery are permitted once you hold the required Home Industry license and Sanitary Permit. Off-island shipping is subject to federal rules. [VERIFY]
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Wholesale to Retailers
Verify Required
Wholesale to shops, restaurants, and retailers is theoretically available to licensed Home Industry operators, but additional labeling and facility requirements may apply. [VERIFY with DEH]
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Farmers Markets & Events
TFSE Permit Required
A Temporary Food Service Establishment (TFSE) Sanitary Permit from DPHSS/DEH is required for each event — including the Chamorro Village Night Market, Dededo Flea Market, and village fiestas.
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Delivery & Pick-Up Orders
Allowed
Home delivery and customer pickup orders are permitted under the Home Industry license as a form of direct-to-consumer sales.
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Off-Island Shipping
Federal Rules Apply
Shipping food products off Guam to the US mainland or other territories triggers federal FDA labeling and interstate commerce rules. [VERIFY specific requirements before shipping off-island]
Storage & Handling Requirements
Room temperature storage is acceptable for confirmed shelf-stable products, but keep them away from direct sunlight and heat. Guam's warm climate can accelerate spoilage in improperly packaged items — use opaque packaging for light-sensitive products.
Packaging must be food-safe and properly sealed. Glass jars with new lids, food-grade resealable bags, and vacuum-sealed pouches are all appropriate. Never reuse old commercial food packaging with another brand's labeling visible.
Label your products with a best-by or use-by date. Even shelf-stable foods degrade in quality over time. Baked goods: 1–4 weeks. Jams and preserves: 1 year unopened, 3 weeks refrigerated after opening. Dry spice blends: up to 1 year.
Separate production from household activities during food preparation. DPHSS/DEH will assess your home kitchen for adequate separation of food production from household use. Having dedicated prep surfaces, utensils, and storage goes a long way during inspection.
Batch records and basic documentation are good practice even if not formally required under the Home Industry license. Recording ingredient lots, production dates, and quantities sold protects you in the rare event of a customer complaint or safety question.
At events and markets, protect shelf-stable products from rain, excessive humidity, and direct sun. Covered display tables and sealed packaging are essential at outdoor markets like the Chamorro Village Night Market.
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