If you have been listening to this podcast from the beginning, I’m sure you will remember my friend Jason, my original podcast partner. I visited him recently in his new home in San Francisco, and I couldn’t pass on the opportunity to record a special episode on technology and food culture in his city. Join me to hear Jason’s insightful overview of various websites and apps that are changing the culture around food and that are thriving in the San Francisco Bay Area, the core of technology and entrepreneurship.
Warning: Just like in my other special with Jason, this episode also starts with me being *very excited*. Again, please bear with me as I gradually calm down 🙂
Along with wine and pasta, olive oil is one of the food items Italy is most known for. Olive oil is the only oil extracted from the actual fruit, as opposed to grains or nuts, and is one of the most ancient manufactured foods.
The production of olive oil started over 5000 years ago in the Mediterranean region, where the olive tree is native. Over time, the production technology has evolved, but the highest quality olive oil is still produced according to the same principles through a process called ‘cold press’. The harvested mature olives, along with their pits, are crushed into a paste, which is then pressed (or nowadays centrifuged) to squeeze out the oil. The resulting product is fruity and aromatic, naturally low in free fatty acids (more on this later in this article), and has high nutritional value, thanks to a high content of vitamin E and other antioxidants. Because of the limited yield of this method, cold press olive oil has a relatively high market cost. As a result, extra virgin oil is normally enjoyed raw as a condiment, more than for cooking, also because of its relatively low smoke point (the temperature at which an oil starts smoking and burning, see the table below).
Smoke points (°C)
When the oil resulting from the cold press method has high acidity levels or other organoleptic defects, it can be refined using a chemical process. Since the process also eliminates part of the phenols and the vitamins, the resulting product has a more neutral flavor and is considered of lower quality from a nutritional point of view. However, refined oil has a higher smoke point, which, combined with a less intense flavor and lower prices, makes refined olive oil the preferred choice for deep frying and sautéing.
With the residues left after the cold press operation, which are called pomace, more oil is extracted by the use of heat and solvents. This “second-squeezing” yields what is called pomace olive oil, which is generally not suitable for human consumption unless mixed with higher quality oils.
As per official European Union regulations, olive oil can have the following denominations:
Oils extracted using purely mechanical means:
‘Olio Extra Vergine di Oliva’ (Extra Virgin Olive Oil), if the percentage of free fatty acids is lower than 0.8%.
‘Olio Vergine di Oliva’ (Virgin Olive Oil), if the percentage of free fatty acids is lower than 2%.
Oils extracted with mechanical means and then chemically refined:
‘Olio di Oliva’ (Olive Oil), obtained with a combination of refined and virgin olive oils.
Oils extracted from pomace using heat and solvents:
‘Olio di Sansa di Olive’ (Pomace Olive Oil), obtained by mixing refined pomace oil and virgin olive oils.
Despite the substantial use of butter in northern Italian cuisine, olive oil is the Italian condiment of choice and it literally defines the cuisine of central and southern Italy. Along the coasts, olive trees are a constant part of the scenery and the production of olives and of olive oil is a central part of the economy (along with Spain, Italy is one of the largest producers, consumers, and exporters of olive oil).
Unlike in North America, where olive oil is very much an elegant aliment used sparingly (olive oil tasting classes are even held), in Italy olive oil is an everyday choice and a very prominent ingredient. Combined with vinegar, it constitutes the most common Italian dressing. On salads, other vegetable oils are also used (e.g. corn oil, sunflower oil) – especially on the more delicate greens – but olive oil is overall the most popular. A drizzle of olive oil is often added on pizza (right before serving, also in its spicy version flavored with chilies) and on some soups (as a finishing touch and not stirred in). Raw olive oil is also one of the main components in many Mediterranean appetizers, including ‘Caprese salad’, ‘bruschetta’ and ‘panzanella’, and used in ‘sottoli’, oil-preserved vegetables and fish in jars.
Olive oil is also used in the preparation of countless Italian dishes. For instance, it is central in the very commonly used ‘soffritto’ (sautéed onion, celery, and carrot), which a lot of dishes are based upon (e.g.: Bolognese sauce, most stews, and several soups). In baking, olive oil is used in specialty bread and focacce. With some exceptions, olive oil is generally not used to make cakes or desserts or used to fry anything sweet (where animal fat or other vegetable oils are preferred for their flavor).
Contrary to popular belief, olive oil is also widely used for deep-frying, especially the less pricey “refined” olive oil (which also features a lower smoke point). Certain preparations specifically rely on the contribution to the flavor that olive oil frying brings (for instance ‘Melanzane alla Parmigiana’ -eggplant parmigiana-). Other vegetable oils are also used for frying (e.g.: peanut oil, sunflower oil, corn oil). But certainly not Canola!
Canola oil is extracted from the seeds of a particular breed of rapeseed (‘colza’ in Italian, scientific name: Brassica napus) which was artificially created in Canada in the ’70s. Natural rapeseed oil is considered inedible for humans because of its flavor and its content of erucic acid (which is mildly toxic). With Canola oil, instead, a much lower content of erucic acid was obtained, as well as better nutritional values and a more neutral flavor. The name ‘Canola’ (which stands for “Canadian oil, low acid”) was chosen to commercially identify the new product and dissociate it from rapeseed oil. In the ’90s, genetically engineered Canola capable to withstand certain types of herbicides was introduced. Not without controversies, this variety of Canola became the standard in North America.
Canola oil is exclusively produced in the United States and Canada, with only small amounts exported (mostly to Mexico and China). Canola oil is virtually absent from Europe where it only exists in its original form (rapeseed) and is used as animal feed and as a source for biodiesel. Despite the North American food organizations describing its properties as remarkable, Europeans are as suspicious of Canola as they are of any genetically modified products (as reflected in the article on the Italian Wikipedia).
Italians in North America strongly dislike Canola oil and find it particularly off-putting as frying oil because of its distinct flavor and smell. Given that refined olive oil is hard to find in North America, foodies have to resort to different oils for deep-frying, or accept that they have to use the more pricey extra virgin oil, and monitor its temperature to avoid reaching its (lower) smoke point.
Aside from their different properties, are some oils healthier than others? All vegetable oils are 100% fat and provide 120 calories per tablespoon, but cooking oils can be quite different from one another. To appreciate these differences, we need to put on our lab coats. In nature, fats and oils are mostly made of one particular kind of lipids: triglycerides, a stable combination of 3 fatty acids and 1 molecule of glycerol. Small amounts of free, unbound, fatty acids are also naturally present (their percentage increases as the oil deteriorates). Since free fatty acids are unstable polarized molecules, they oxidize and cause the oil to go rancid.
Lipids, in general, can be subdivided into two main categories based on their hydrogen content:
Saturated fats accommodate the maximum possible number of hydrogen atoms. Saturation causes the fatty acids to be perfectly straight and this allows them to fit tightly one alongside the other. Because of this, saturated fats are usually solid at room temperature and are chemically quite stable – they naturally resist oxidation and have a relatively long shelf life. However, studies show that saturated fats are linked to high cholesterol and may cause heart diseases. Most saturated fats are of animal origin (e.g.: butter, cream, lard), but highly saturated molecules are also contained in tropical oils (e.g.: coconut oil).
Unsaturated fats contain a certain number of double bonds between carbon atoms, and consequently fewer hydrogen atoms. In unsaturated fats, the lack of symmetry causes the fatty acids to bend into more irregularly shaped molecules. As a result, unsaturated fats are generally liquid at room temperature and they are more subject to oxidation (to be preserved, they need to be kept away from light and heat). There is some evidence that unsaturated fats help lower blood cholesterol levels. Particularly, monounsaturated fatty acids (those where there is only one double-bond) seem to selectively lower only low-density lipoproteins levels while keeping high-density lipoproteins levels intact (the so-called “good cholesterol”). Monounsaturated fats are also preferred for frying as polyunsaturated oils tend to break down more easily at high temperatures. Canola, olive, and peanut oil are all classified as monounsaturated fats. Corn, soybean, sunflower oils are instead mostly polyunsaturated.
Finally, here is a diagram that shows the proportions of saturated, monounsaturated and polyunsaturated fatty acids in the most common cooking oils (data from “Harold McGee. On Food and Cooking: The Science and Lore of the Kitchen. 2nd edition (2004) – page 800″).
Cooking oils classification
Even though Canola oil has the lowest percentage of saturated fats, some regard olive oil as the healthiest cooking oil because of its higher percentage of monounsaturated fats. However, the percentage of saturated fats is comparably low in both oils, leaving the ultimate choice to flavor and personal preference.
For a blog that talks about Italian food compared to its North American counterpart, milk is probably one of the less obvious choices of topics. But if cow milk is similar, how milk differs as a product and how Italians and North Americans look at it can be quite interesting. For instance, it is perfectly normal for Italians to buy fresh milk with a shelf life of 2 days, or meant to be stored unrefrigerated for months before consumption.
Before we venture ourselves into the different preservation techniques, let’s talk for a moment about the relationship between Italians and milk. Italians like fresh milk just as much as North Americans do, but research shows that its consumption as a drink is less in Italian adults. A glass of milk isn’t commonly available in coffee bars and especially in restaurants because Italians don’t have milk with their meals. Flavored milk is also quite uncommon in Italy – chocolate milk does exist, but is only meant for young children (and is not as dense as the North American one). The consumption of milk-derived products, such as cheese, is instead higher in Italy.
Flavor-wise, Italian milk can taste quite different from the North American one. Flavor largely depends on how the cows are fed. For instance, a prevalently dry hay diet produces a mildly cheesy aroma, while lush pasturage produces sweeter flavors, but also barnyard indoles(3). Homogenization and pasteurization, which are nowadays standard for almost all milk, also affect the flavor.
Homogenization is a treatment developed in France around 1900 to prevent milk cream from rising to the top. The homogenization process breaks down the fat globules into smaller ones (from 4 μm to 1 μm). Caseine particles form a coating around the fat globules and this weighs them down and interferes with their ability to clump, keeping them evenly dispersed in the milk. The structural changes introduced by homogenization cause the milk to taste blander, but also feel creamier, and appear whiter(3).
The use of heat as a way to sanitize milk has been documented since the 1820s, but it took until the beginning of the 20th century for milk pasteurization to be regulated and required by the governments(3). Raw unpasteurized milk can, in fact, be quite harmful, as it has a relatively high chance to become infected with dangerous bacteria including salmonella and listeria. Nowadays, raw milk is illegal in Canada, whereas in Italy and in the U.S. its commercialization is restricted to authorized farms (which must be frequently inspected) that can only sell directly to the public within their premises.
The effects of thermal processing on milk vary based on its intensity and provide different levels of sanitation, shelf life extension, and side-effects on flavor and nutritional values. The following treatments are considered standard(2):
Thermalization: 20 seconds at ~65°C. The process kills many vegetative organisms and bacteria that produce enzymes that eventually cause milk deterioration. In the dairy industry, milk is often thermalized before undergoing further processing. Flavor and nutritional properties are unaltered.
Low pasteurization: 30 minutes at 63°C, or 15 seconds at 72°C. The latter is referred to as Flash Pasteurization or HTST (high temperature, short-time) and is considered the pasteurization standard for milk. It represents the minimum requirement by law in many countries (including Italy, the U.S., and Canada). Low pasteurized milk is safe to drink because all yeasts, molds, and pathogen bacteria have been killed. However, bacterial spores and some enzymes are preserved. Even if refrigerated, shelf life is limited to 1 or 2 weeks (depending on the milk’s “keeping qualities”). At strict HTST intensity, the flavor is almost unaltered and so are the nutritional properties. The slightly higher time and temperature (20 seconds at 75°C) required by homogenized milk are however sufficient to introduce small alterations.
High pasteurization: 20 seconds at 85-100°C. This process, which essentially consists of a short boiling, kills all vegetative organisms and deactivates most enzymes, although still doesn’t affect bacterial spores. High pasteurized milk has a longer shelf life but is more vulnerable to post-processing contamination because the higher temperatures also eliminate the bacterial growth inhibitors. As a result, this type of pasteurization is usually operated on the bottled product. The milk serum starts to denature and a “cooked” flavor develops. The nutritional properties are slightly reduced because of a loss of vitamin C.
Sterilization: 30 minutes at 110°C (prolonged boiling), or Ultra-High Temperature processes (UHT) ranging between 30 seconds at 130°C, and 1 second at 145°C. UHT milk (called “ultrapasteurized” in the United States) is preferred over milk sterilized by prolonged boiling because of the more limited browning and a better flavor. Shelf life is generally between 3 and 6 months, unrefrigerated. Once opened, it only lasts for 3-4 days at 4°C because natural bacteria inhibitors have been destroyed by the heating process. The nutritional value of UHT milk is reduced, but it is still a great source of essential nutrients such as calcium and proteins. UHT milk is particularly useful in all cases where transportation or storage of fresh milk is impossible, as well as for all uses that call for boiled milk. UHT milk is very common in Italy, where it represents almost 50% of the entire milk consumption, Italians are mostly used to its flavor and some even prefer it over fresh milk. North America, instead, resists the introduction of UHT because of its flavor and because it’s deemed not acceptable that milk can be stored unrefrigerated.
In recent years, the milk industry has devised an alternative to UHT which is also capable of extending shelf life, still without using preservatives. Through a process called “microfiltration”, between 99.0 and 99.9% of bacterial cells (including most spores) are removed by using ceramic membranes with pore sizes of about 1 μm(2). Since the fat globules are also about 1 μm in diameter, before microfiltration the milk’s cream is separated, sterilized using a regular UHT treatment, and then added back. Microfiltered milk is nutritionally equivalent to regular pasteurized milk, but with a longer shelf life of up to 3-4 weeks, if properly refrigerated. Flavor-wise, it’s considered similar to regular pasteurized milk, but with a creamier texture.
Under the same storage temperatures, milk’s shelf life depends on its “keeping quality”, which derives from the quality of the raw milk, the type of pasteurization, and the level of post-processing contamination(1). Keeping quality varies from country to country based on shelf life demand. In Italy, an expiry date of only a few days in the future is considered acceptable for milk, since it’s quite common to buy fresh ailments daily. In North America, a minimum of 2 weeks is generally the requirement.
Because of the shorter shelf life of fresh milk, Italian milk is sold almost exclusively in 1-liter containers. UHT milk is also sold in 1-liter containers because of its limited expiry time once opened. North American milk instead supports larger formats up to 4 liters, or 1 gallon (in the U.S.).
Another important difference between Italian and North American milk is in the use of “fortification”. In Canada and the US, by law, vitamin A (a fat-soluble vitamin) is added to all skimmed milk to compensate for the amount that was removed when the milk was skimmed. Milk is also fortified with vitamin D, as regulated by law, to compensate for the lack of exposure of the cattle to direct sunlight. Italian milk has no additives.
Finally, as a summary of the differences here is a comparison table.
North American Milk
Italian Milk
Percentages of fat available
• Whole (3.5% to 3.8%, called Homogenized in Canada).
• 2% or “Reduced fat”.
• 1% or “Low-fat”.
• Semi-skimmed 1.8% (not available in Canada).
• Skimmed (less than 0.5%).
• Whole (3.5% fat min).
• Partly skimmed (1.5% to 1.8%).
• Skimmed (less than 0.3%).
Retail sizes
Containers up to 1 gallon (4 liters in Canada).
Containers usually only up to 1 liter.
Fortification
Vitamins A added to all skimmed milk. Vitamin D added to all milk.
No vitamins added – vitamins are not even mentioned in the nutritional info.
Types of sanitation
• Raw milk – illegal in Canada, rare in the U.S.
• Pasteurized: 2+ weeks shelf life at 4°C max.
• Microfiltered pasteurized – not very common. 3-4 weeks shelf life at 4°C max.
• Long preservation milk (UHT) – rarely available. Over 3 months shelf life at room temperature.
• Raw milk legal if sold on the premises from the producer.
• Pasteurized milk(*) or Fresh Pasteurized milk(**): 6 days shelf life at 4°C max.
• Microfiltered pasteurized milk. 2-3 weeks shelf life at 4°C max.
• Long preservation milk (UHT). Over 3 months shelf life at room temperature.
(*) Milk proteins at least 11% of the total proteins. (**) Pasteurization has to occur within 48 hrs from milking. Milk proteins at least 14% of the total (when over 15.5%, can be labeled “High Quality”).
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